gson | Java serialization/deserialization library | JSON Processing library

interface ApiServiceInterface {

    companion object Factory{

        fun create(): ApiServiceInterface {
            val interceptor = HttpLoggingInterceptor()
            interceptor.level = HttpLoggingInterceptor.Level.BODY
            
            val stringInterceptor = Interceptor { chain: Interceptor.Chain ->
                val request = chain.request()
                val response = chain.proceed(request)
                val source = response.body()?.source()
                source?.request(Long.MAX_VALUE)
                val buffer = source?.buffer()
                var responseString = buffer?.clone()?.readString(Charset.forName("UTF-8"))
                if (responseString != null && responseString.length > 2) {
                    val lastTwo = responseString.takeLast(2)
                    if (lastTwo != "}}") {
                        val lastOne = responseString.takeLast(1)
                        responseString = if (lastOne != "}") {
                            "$responseString}}"
                        } else {
                            "$responseString}"
                        }
                    }
                }
                val contentType = response.body()?.contentType()
                val body = ResponseBody.create(contentType, responseString ?: "")
                return@Interceptor response.newBuilder().body(body).build()
            }

            val client = OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30,TimeUnit.SECONDS)
                .addInterceptor(interceptor)
                .addInterceptor(stringInterceptor)
                .retryOnConnectionFailure(true)
                .connectionPool(ConnectionPool(0, 5, TimeUnit.MINUTES))
                .protocols(listOf(Protocol.HTTP_1_1))
                .build()
            val gson = GsonBuilder().create()
            val retrofit = Retrofit.Builder()
                .addCallAdapterFactory(CoroutineCallAdapterFactory())
                .addConverterFactory(GsonConverterFactory.create(gson))
                .addConverterFactory(ScalarsConverterFactory.create())
                .baseUrl("http://3.124.6.203:5000")
                .client(client)
                .build()
            return retrofit.create(ApiServiceInterface::class.java)
        }
    }


    @Headers("Content-type: application/json", "Connection: close", "Accept-Encoding: identity")
    @POST("/")
    fun requestAsync(@Body data: JsonObject): Deferred<Response>
}

return GsonBuilder().create().fromJson(
    json,
    object : TypeToken<List<Question>?>() {}.type
)

return GsonBuilder().create().fromJson(
    json,
    TypeToken.getParameterized(List::class.java, Question::class.java).type
)

return GsonBuilder().create().fromJson(
    json,
    object : TypeToken<List<Question>?>() {}.type
)

return GsonBuilder().create().fromJson(
    json,
    TypeToken.getParameterized(List::class.java, Question::class.java).type
)

# Retain generic signatures of TypeToken and its subclasses with R8 version 3.0 and higher.
-keep,allowobfuscation,allowshrinking class com.google.gson.reflect.TypeToken
-keep,allowobfuscation,allowshrinking class * extends com.google.gson.reflect.TypeToken

<receiver android:name="<name_of_the_entry>"
                android:exported="false or true"
                tools:node="merge" />

     <activity
                android:name="<activity which is giving error>"
                android:exported="true"
                tools:node="merge" />

<activity android:name="name_of_the_activity_inside_library>"
    android:exported="false|true"
    tools:node="merge" />

debugImplementation "androidx.fragment:fragment-testing:<version>"

androidTestImplementation "androidx.fragment:fragment-testing:<version>"

debugImplementation "androidx.fragment:fragment-testing:<version>"

androidTestImplementation "androidx.fragment:fragment-testing:<version>"

 android:exported="true"

androidTestImplementation "androidx.test.ext:junit:1.1.3"
androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.0.4"

> java.util.concurrent.ExecutionException: com.android.builder.testing.api.DeviceException: com.android.ddmlib.InstallException: INSTALL_PARSE_FAILED_MANIFEST_MALFORMED: Failed parse during installPackageLI: /data/app/xxxxx.tmp/base.apk (at Binary XML file line #129): YOUR.FULLY.QUALIFIED.NAME.FAILING.ACTIVITY: Targeting S+ (version 31 and above) requires that an explicit value for android:exported be defined when intent filters are present

<activity android:name="androidx.test.core.app.InstrumentationActivityInvoker$BootstrapActivity"
android:exported="true"
tools:node="merge"/>

<activity android:name="androidx.test.core.app.InstrumentationActivityInvoker$EmptyActivity"
android:exported="true"
tools:node="merge"/>

<activity android:name="androidx.test.core.app.InstrumentationActivityInvoker$EmptyFloatingActivity"
android:exported="true"
tools:node="merge"/>

 <activity
        android:name="com.test.activity.SplashActivity"
        android:clearTaskOnLaunch="true"
        android:label="@string/app_name"
        android:launchMode="singleTop"
        android:noHistory="true"
        android:screenOrientation="portrait"
        android:theme="@style/AppTheme.NoActionBar"
        android:exported="true">

   <receiver
        android:name="com.test.receiver.ShareReceiver"
        android:exported="true">
        <intent-filter>
            <action android:name="com.test.fcm.android.action.broadcast" />
        </intent-filter>
    </receiver>

   <service
        android:name="com.google.android.gms.tagmanager.InstallReferrerService"
        android:exported="true" />

testImplementation 'junit:junit:4.13.2' 
androidTestImplementation 'androidx.test:runner:1.4.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation 'com.razorpay:checkout:1.6.15'

 <activity
        android:name="com.test.activity.SplashActivity"
        android:clearTaskOnLaunch="true"
        android:label="@string/app_name"
        android:launchMode="singleTop"
        android:noHistory="true"
        android:screenOrientation="portrait"
        android:theme="@style/AppTheme.NoActionBar"
        android:exported="true">

   <receiver
        android:name="com.test.receiver.ShareReceiver"
        android:exported="true">
        <intent-filter>
            <action android:name="com.test.fcm.android.action.broadcast" />
        </intent-filter>
    </receiver>

   <service
        android:name="com.google.android.gms.tagmanager.InstallReferrerService"
        android:exported="true" />

testImplementation 'junit:junit:4.13.2' 
androidTestImplementation 'androidx.test:runner:1.4.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation 'com.razorpay:checkout:1.6.15'

 <activity
        android:name="com.test.activity.SplashActivity"
        android:clearTaskOnLaunch="true"
        android:label="@string/app_name"
        android:launchMode="singleTop"
        android:noHistory="true"
        android:screenOrientation="portrait"
        android:theme="@style/AppTheme.NoActionBar"
        android:exported="true">

   <receiver
        android:name="com.test.receiver.ShareReceiver"
        android:exported="true">
        <intent-filter>
            <action android:name="com.test.fcm.android.action.broadcast" />
        </intent-filter>
    </receiver>

   <service
        android:name="com.google.android.gms.tagmanager.InstallReferrerService"
        android:exported="true" />

testImplementation 'junit:junit:4.13.2' 
androidTestImplementation 'androidx.test:runner:1.4.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
implementation 'com.razorpay:checkout:1.6.15'

"com.google.dagger:hilt-android:2.38.1"
"com.google.dagger:hilt-android-gradle-plugin:2.38.1"
"com.google.dagger:hilt-android-compiler:2.38.1"
"com.google.dagger:hilt-android-testing:2.38.1"

"com.google.dagger:hilt-android:2.40.5"
"com.google.dagger:hilt-android-gradle-plugin:2.40.5"
"com.google.dagger:hilt-android-compiler:2.40.5"
"com.google.dagger:hilt-android-testing:2.40.5" 

"com.google.dagger:hilt-android:2.38.1"
"com.google.dagger:hilt-android-gradle-plugin:2.38.1"
"com.google.dagger:hilt-android-compiler:2.38.1"
"com.google.dagger:hilt-android-testing:2.38.1"

"com.google.dagger:hilt-android:2.40.5"
"com.google.dagger:hilt-android-gradle-plugin:2.40.5"
"com.google.dagger:hilt-android-compiler:2.40.5"
"com.google.dagger:hilt-android-testing:2.40.5" 

<receiver
    android:name="com.razorpay.RzpTokenReceiver"
    android:exported="false">
    <intent-filter>
        <action android:name="rzp.device_token.share" />
    </intent-filter>
</receiver>

<activity
    android:name="com.razorpay.CheckoutActivity"
    android:configChanges="keyboard|keyboardHidden|orientation|screenSize"
    android:exported="true"
    android:theme="@style/CheckoutTheme">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <data
            android:host="rzp.io"
            android:scheme="io.rzp" />
    </intent-filter>
</activity>

android:exported="true" <!-- or false as required -->

<activity
     android:name=".MainActivity"
     android:exported="true" <** add this line on AndroidManifest.xml**
     android:launchMode="singleTop"
     android:theme="@style/LaunchTheme"
 </activity>

compileSdk = 31

classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.10'

implementation 'androidx.appcompat:appcompat:1.3.0'

configurations.all {
        resolutionStrategy.force 'androidx.appcompat:appcompat:1.3.0'
    }

    repositories {
        mavenCentral()
        google()
    }

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        mavenCentral()
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.1.1'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        mavenCentral()
        google()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

data class DetailModel(val id: String = "", val success: Boolean, val cache_last_updated: Long, val total: Int) 

interface apiService {
    @GET("....")
    fun getWalletResume( listAddress: List<String> ): Call<Map<String, DetailModel>>
}

val json = """
    {
      "0x1234": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 500
      },
      "0x1244445": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 324
      },
      "0x47851": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 324
      }
    }
""".trimIndent()


data class DetailModel(val id: String = "", val success: Boolean, val cache_last_updated: Long, val total: Int)

fun main() {
    val gson = Gson()
    val type: Type = object : TypeToken<Map<String, DetailModel>?>() {}.type
    
    // step 1. simulates the retrofit call
    val mapResult: Map<String, DetailModel> = gson.fromJson(json, type)

    // step 2
    val result = mapResult.map { entry -> entry.value.copy(id = entry.key) }

    println(result) 
    // [DetailModel(id=0x1234, success=true, cache_last_updated=1642815869695, total=500), DetailModel(id=0x1244445, success=true, cache_last_updated=1642815869695, total=324), DetailModel(id=0x47851, success=true, cache_last_updated=1642815869695, total=324)]
}

data class DetailModel(val id: String = "", val success: Boolean, val cache_last_updated: Long, val total: Int) 

interface apiService {
    @GET("....")
    fun getWalletResume( listAddress: List<String> ): Call<Map<String, DetailModel>>
}

val json = """
    {
      "0x1234": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 500
      },
      "0x1244445": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 324
      },
      "0x47851": {
        "success": true,
        "cache_last_updated": 1642815869695,
        "total": 324
      }
    }
""".trimIndent()


data class DetailModel(val id: String = "", val success: Boolean, val cache_last_updated: Long, val total: Int)

fun main() {
    val gson = Gson()
    val type: Type = object : TypeToken<Map<String, DetailModel>?>() {}.type
    
    // step 1. simulates the retrofit call
    val mapResult: Map<String, DetailModel> = gson.fromJson(json, type)

    // step 2
    val result = mapResult.map { entry -> entry.value.copy(id = entry.key) }

    println(result) 
    // [DetailModel(id=0x1234, success=true, cache_last_updated=1642815869695, total=500), DetailModel(id=0x1244445, success=true, cache_last_updated=1642815869695, total=324), DetailModel(id=0x47851, success=true, cache_last_updated=1642815869695, total=324)]
}

@GET("....")
suspend fun getWalletDetails(...): Map<String, WalletDetailDTO>

val mapOfWalletDetails = apiService.getWalletResume(...)

val walletDetailCollection: Collection<WalletDetailDTO> = mapOfWalletDetails.values()

@GET("....")
suspend fun getWalletDetails(...): Map<String, WalletDetailDTO>

val mapOfWalletDetails = apiService.getWalletResume(...)

val walletDetailCollection: Collection<WalletDetailDTO> = mapOfWalletDetails.values()

graphQlBody = { "query" : mutation_query, "variables" : { "eventLog" : event_log_json } }

public Mono<String> sendLogsToGraphQL(Map<String,Object> body){
    return webClient
            .post()
            .uri("http://localhost:8080/logs/createEventLog")
            .bodyValue(BodyInserters.fromValue(body))
            .retrieve()
            .bodyToMono(String.class);
}  

graphQlBody = { "query" : mutation_query, "variables" : { "eventLog" : event_log_json } }

public Mono<String> sendLogsToGraphQL(Map<String,Object> body){
    return webClient
            .post()
            .uri("http://localhost:8080/logs/createEventLog")
            .bodyValue(BodyInserters.fromValue(body))
            .retrieve()
            .bodyToMono(String.class);
}  

image="testing"
targetDir="target"
lowerDir="$(docker inspect --format "{{ .GraphDriver.Data.LowerDir }}" $image)"
upperDir="$(docker inspect --format "{{ .GraphDriver.Data.UpperDir }}" $image)"
workDir="$(docker inspect --format "{{ .GraphDriver.Data.WorkDir }}" $image)"
mergedDir="/mnt/$targetDir"

sudo mkdir "$mergedDir"
echo "mounting in $mergedDir ..."
sudo mount -t overlay -o lowerdir=$lowerDir,upperdir=$upperDir,workdir=$workDir overlay "$mergedDir"
echo "copying $mergedDir in $targetDir/ ..."
sudo cp -a "$mergedDir/." "$targetDir/" 
echo "unmounting $mergedDir ..."
sudo umount overlay
sudo rmdir "$mergedDir"

docker create your_image sh

docker cp your_container_name:/ custom_directory

docker inspect --format "{{ json .GraphDriver.Data }}" container_name

skopeo copy docker-daemon:your_image:your_tag "dir:$(pwd)/dir_for_layers"

image="testing"
targetDir="target"
lowerDir="$(docker inspect --format "{{ .GraphDriver.Data.LowerDir }}" $image)"
upperDir="$(docker inspect --format "{{ .GraphDriver.Data.UpperDir }}" $image)"
workDir="$(docker inspect --format "{{ .GraphDriver.Data.WorkDir }}" $image)"
mergedDir="/mnt/$targetDir"

sudo mkdir "$mergedDir"
echo "mounting in $mergedDir ..."
sudo mount -t overlay -o lowerdir=$lowerDir,upperdir=$upperDir,workdir=$workDir overlay "$mergedDir"
echo "copying $mergedDir in $targetDir/ ..."
sudo cp -a "$mergedDir/." "$targetDir/" 
echo "unmounting $mergedDir ..."
sudo umount overlay
sudo rmdir "$mergedDir"

docker create your_image sh

docker cp your_container_name:/ custom_directory

docker inspect --format "{{ json .GraphDriver.Data }}" container_name

skopeo copy docker-daemon:your_image:your_tag "dir:$(pwd)/dir_for_layers"

image="testing"
targetDir="target"
lowerDir="$(docker inspect --format "{{ .GraphDriver.Data.LowerDir }}" $image)"
upperDir="$(docker inspect --format "{{ .GraphDriver.Data.UpperDir }}" $image)"
workDir="$(docker inspect --format "{{ .GraphDriver.Data.WorkDir }}" $image)"
mergedDir="/mnt/$targetDir"

sudo mkdir "$mergedDir"
echo "mounting in $mergedDir ..."
sudo mount -t overlay -o lowerdir=$lowerDir,upperdir=$upperDir,workdir=$workDir overlay "$mergedDir"
echo "copying $mergedDir in $targetDir/ ..."
sudo cp -a "$mergedDir/." "$targetDir/" 
echo "unmounting $mergedDir ..."
sudo umount overlay
sudo rmdir "$mergedDir"

docker create your_image sh

docker cp your_container_name:/ custom_directory

docker inspect --format "{{ json .GraphDriver.Data }}" container_name

skopeo copy docker-daemon:your_image:your_tag "dir:$(pwd)/dir_for_layers"

image="testing"
targetDir="target"
lowerDir="$(docker inspect --format "{{ .GraphDriver.Data.LowerDir }}" $image)"
upperDir="$(docker inspect --format "{{ .GraphDriver.Data.UpperDir }}" $image)"
workDir="$(docker inspect --format "{{ .GraphDriver.Data.WorkDir }}" $image)"
mergedDir="/mnt/$targetDir"

sudo mkdir "$mergedDir"
echo "mounting in $mergedDir ..."
sudo mount -t overlay -o lowerdir=$lowerDir,upperdir=$upperDir,workdir=$workDir overlay "$mergedDir"
echo "copying $mergedDir in $targetDir/ ..."
sudo cp -a "$mergedDir/." "$targetDir/" 
echo "unmounting $mergedDir ..."
sudo umount overlay
sudo rmdir "$mergedDir"

docker create your_image sh

docker cp your_container_name:/ custom_directory

docker inspect --format "{{ json .GraphDriver.Data }}" container_name

skopeo copy docker-daemon:your_image:your_tag "dir:$(pwd)/dir_for_layers"

image="testing"
targetDir="target"
lowerDir="$(docker inspect --format "{{ .GraphDriver.Data.LowerDir }}" $image)"
upperDir="$(docker inspect --format "{{ .GraphDriver.Data.UpperDir }}" $image)"
workDir="$(docker inspect --format "{{ .GraphDriver.Data.WorkDir }}" $image)"
mergedDir="/mnt/$targetDir"

sudo mkdir "$mergedDir"
echo "mounting in $mergedDir ..."
sudo mount -t overlay -o lowerdir=$lowerDir,upperdir=$upperDir,workdir=$workDir overlay "$mergedDir"
echo "copying $mergedDir in $targetDir/ ..."
sudo cp -a "$mergedDir/." "$targetDir/" 
echo "unmounting $mergedDir ..."
sudo umount overlay
sudo rmdir "$mergedDir"

docker create your_image sh

docker cp your_container_name:/ custom_directory

docker inspect --format "{{ json .GraphDriver.Data }}" container_name

skopeo copy docker-daemon:your_image:your_tag "dir:$(pwd)/dir_for_layers"

# create container from image without starting it
docker create --name my_container my_image

# export container file system to tar archive
docker export -o my_image.tar my_container

# or directly extract the archive in the current folder
docker export my_container | tar -x

# clean up temporary container
docker rm my_container

FROM busybox as build
COPY ./source.tgz /app/source.tgz
WORKDIR /app
RUN tar -xzf ./source.tgz \
 && ./install.sh
RUN rm ./source.tgz 

FROM busybox as release
COPY --from=build /app /app

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

  <groupId>gd.wa</groupId>
  <artifactId>minimal-pom</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>
  <modelVersion>4.0.0</modelVersion>

  <dependencies>
    <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-compress -->
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-compress</artifactId>
      <version>1.21</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
    <dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.8.9</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.11.0</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.13</version>
    </dependency>
  </dependencies>

  <properties>
    <java.version>1.8</java.version>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
</project>

package com.sonatype.docker.poc;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

import com.google.gson.Gson;
import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
import org.apache.commons.io.IOUtils;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

public class Main
{
  static class TokenResponse
  {
    String access_token;
  }

  static class Layer
  {
    String digest;

    long size;
  }

  static class ManifestResponse
  {
    List<Layer> layers;
  }

  static String imageName = "httpd";

  static String repoName = "library";

  static String base64EncodedUsernamePassword = "username:password[base64-encoded]";

  public static void main(String[] args) throws Exception {
    try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
      // Get a token
      HttpGet httpget = new HttpGet(
          "https://auth.docker.io/token?service=registry.docker.io&scope=repository:" + repoName + "/" + imageName +
              ":pull");
      httpget.setHeader("Authorization", "Basic " + base64EncodedUsernamePassword);

      CloseableHttpResponse response = httpclient.execute(httpget);
      String text = IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8.name());
      String token = new Gson().fromJson(text, TokenResponse.class).access_token;

      // Get the list of layers
      httpget = new HttpGet("https://registry-1.docker.io/v2/" + repoName + "/" + imageName + "/manifests/latest");
      httpget.setHeader("Authorization", "Bearer " + token);
      httpget.setHeader("Accept", "application/vnd.docker.distribution.manifest.v2+json");

      response = httpclient.execute(httpget);
      text = IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8.name());
      ManifestResponse manifestResponse = new Gson().fromJson(text, ManifestResponse.class);

      List<File> files = new ArrayList<>();

      int counter = 100;

      // Download layers (tar files)
      for (Layer layer : manifestResponse.layers) {
        System.out.println("Downloading layer: " + layer.digest);
        System.out.println("Layer size:" + layer.size + " bytes.(" + ((double) layer.size) / 1_000_000 + " MB)");
        httpget =
            new HttpGet("https://registry-1.docker.io/v2/" + repoName + "/" + imageName + "/blobs/" + layer.digest);
        httpget.setHeader("Authorization", "Bearer " + token);
        httpget.setHeader("Accept", "application/vnd.docker.image.rootfs.foreign.diff.tar.gzip");

        response = httpclient.execute(httpget);
        File targetFile = new File(counter + "_" + layer.digest.substring(7, 17) + ".tar");
        counter++;
        files.add(targetFile);

        InputStream inputStream = response.getEntity().getContent();
        OutputStream outputStream = new FileOutputStream(targetFile);
        IOUtils.copy(inputStream, outputStream);
        inputStream.close();
        outputStream.close();
      }

      unTarGz(files);
    }
  }

  public static void unTarGz(List<File> files) throws IOException {
    for (File file : files) {
      TarArchiveInputStream tararchiveinputstream =
          new TarArchiveInputStream(
              new GzipCompressorInputStream(
                  new BufferedInputStream(Files.newInputStream(file.toPath()))));

      ArchiveEntry archiveentry;
      while ((archiveentry = tararchiveinputstream.getNextEntry()) != null) {
        Path pathEntryOutput = Paths.get("./fs").resolve(archiveentry.getName());
        if (archiveentry.isDirectory()) {
          if (!Files.exists(pathEntryOutput)) {
            Files.createDirectory(pathEntryOutput);
          }
        }
        else {
          if (archiveentry.getName().contains(".wh")) {
            try {
              Files.delete(Paths.get("./fs").resolve(archiveentry.getName().replace(".wh.", "")));
            }
            catch (NoSuchFileException noSuchFileException) {
              noSuchFileException.printStackTrace();
            }
          }
          else {
            if (Files.exists(pathEntryOutput)) {
              Files.delete(pathEntryOutput);
            }
            Files.copy(tararchiveinputstream, pathEntryOutput);
          }
        }
      }

      tararchiveinputstream.close();
    }
  }
}

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

  <groupId>gd.wa</groupId>
  <artifactId>minimal-pom</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>
  <modelVersion>4.0.0</modelVersion>

  <dependencies>
    <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-compress -->
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-compress</artifactId>
      <version>1.21</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
    <dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.8.9</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.11.0</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.13</version>
    </dependency>
  </dependencies>

  <properties>
    <java.version>1.8</java.version>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
</project>

package com.sonatype.docker.poc;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

import com.google.gson.Gson;
import org.apache.commons.compress.archivers.ArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
import org.apache.commons.io.IOUtils;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

public class Main
{
  static class TokenResponse
  {
    String access_token;
  }

  static class Layer
  {
    String digest;

    long size;
  }

  static class ManifestResponse
  {
    List<Layer> layers;
  }

  static String imageName = "httpd";

  static String repoName = "library";

  static String base64EncodedUsernamePassword = "username:password[base64-encoded]";

  public static void main(String[] args) throws Exception {
    try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
      // Get a token
      HttpGet httpget = new HttpGet(
          "https://auth.docker.io/token?service=registry.docker.io&scope=repository:" + repoName + "/" + imageName +
              ":pull");
      httpget.setHeader("Authorization", "Basic " + base64EncodedUsernamePassword);

      CloseableHttpResponse response = httpclient.execute(httpget);
      String text = IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8.name());
      String token = new Gson().fromJson(text, TokenResponse.class).access_token;

      // Get the list of layers
      httpget = new HttpGet("https://registry-1.docker.io/v2/" + repoName + "/" + imageName + "/manifests/latest");
      httpget.setHeader("Authorization", "Bearer " + token);
      httpget.setHeader("Accept", "application/vnd.docker.distribution.manifest.v2+json");

      response = httpclient.execute(httpget);
      text = IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8.name());
      ManifestResponse manifestResponse = new Gson().fromJson(text, ManifestResponse.class);

      List<File> files = new ArrayList<>();

      int counter = 100;

      // Download layers (tar files)
      for (Layer layer : manifestResponse.layers) {
        System.out.println("Downloading layer: " + layer.digest);
        System.out.println("Layer size:" + layer.size + " bytes.(" + ((double) layer.size) / 1_000_000 + " MB)");
        httpget =
            new HttpGet("https://registry-1.docker.io/v2/" + repoName + "/" + imageName + "/blobs/" + layer.digest);
        httpget.setHeader("Authorization", "Bearer " + token);
        httpget.setHeader("Accept", "application/vnd.docker.image.rootfs.foreign.diff.tar.gzip");

        response = httpclient.execute(httpget);
        File targetFile = new File(counter + "_" + layer.digest.substring(7, 17) + ".tar");
        counter++;
        files.add(targetFile);

        InputStream inputStream = response.getEntity().getContent();
        OutputStream outputStream = new FileOutputStream(targetFile);
        IOUtils.copy(inputStream, outputStream);
        inputStream.close();
        outputStream.close();
      }

      unTarGz(files);
    }
  }

  public static void unTarGz(List<File> files) throws IOException {
    for (File file : files) {
      TarArchiveInputStream tararchiveinputstream =
          new TarArchiveInputStream(
              new GzipCompressorInputStream(
                  new BufferedInputStream(Files.newInputStream(file.toPath()))));

      ArchiveEntry archiveentry;
      while ((archiveentry = tararchiveinputstream.getNextEntry()) != null) {
        Path pathEntryOutput = Paths.get("./fs").resolve(archiveentry.getName());
        if (archiveentry.isDirectory()) {
          if (!Files.exists(pathEntryOutput)) {
            Files.createDirectory(pathEntryOutput);
          }
        }
        else {
          if (archiveentry.getName().contains(".wh")) {
            try {
              Files.delete(Paths.get("./fs").resolve(archiveentry.getName().replace(".wh.", "")));
            }
            catch (NoSuchFileException noSuchFileException) {
              noSuchFileException.printStackTrace();
            }
          }
          else {
            if (Files.exists(pathEntryOutput)) {
              Files.delete(pathEntryOutput);
            }
            Files.copy(tararchiveinputstream, pathEntryOutput);
          }
        }
      }

      tararchiveinputstream.close();
    }
  }
}

data -> session.textMessage(gson.toJson(data))

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }

implementation 'com.anjlab.android.iab.v3:library:1.1.0'

implementation 'com.android.billingclient:billing:4.0.0'

<string name="license_key">Place Your ID Here</string>
<string name="product_id">android.test.purchased</string>

import android.app.Activity
import android.content.Context
import android.widget.Toast
import com.android.billingclient.api.*
import java.io.IOException
import java.util.ArrayList

class InAppPurchase(context: Context) : PurchasesUpdatedListener{
    private val mContext: Context = context
    private var billingClient: BillingClient
    var ackPurchase =
        AcknowledgePurchaseResponseListener { billingResult ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                //if purchase is acknowledged
                // Grant entitlement to the user. and restart activity
                SharedPreferencesUtils.setPurchasedBillingValue(mContext, true)
                showMessage("Item Purchased")
                (mContext as Activity).recreate()
            }
        }

    init {
        billingClient =
            BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
        billingClient.startConnection(object : BillingClientStateListener {
            override fun onBillingSetupFinished(billingResult: BillingResult) {
                if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                    val queryPurchase = billingClient.queryPurchases(BillingClient.SkuType.INAPP)
                    val queryPurchases = queryPurchase.purchasesList
                    if (queryPurchases != null && queryPurchases.size > 0) {
                        handlePurchases(queryPurchases)
                    } else {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext, false)
                    }
                }
            }

            override fun onBillingServiceDisconnected() {}
        })
    }

    fun productPurchase() {
        //check if service is already connected
        if (billingClient.isReady) {
            initiatePurchase()
        } else {
            billingClient =
                BillingClient.newBuilder(mContext).enablePendingPurchases().setListener(this).build()
            billingClient.startConnection(object : BillingClientStateListener {
                override fun onBillingSetupFinished(billingResult: BillingResult) {
                    if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                        initiatePurchase()
                    } else {
                        showMessage("Error" + billingResult.debugMessage)
                    }
                }

                override fun onBillingServiceDisconnected() {}
            })
        }
    }

    private fun initiatePurchase() {
        val skuList: MutableList<String> = ArrayList()
        skuList.add(mContext.resources.getString(R.string.product_id))
        val params = SkuDetailsParams.newBuilder()
        params.setSkusList(skuList).setType(BillingClient.SkuType.INAPP)
        billingClient.querySkuDetailsAsync(
            params.build()
        ) { billingResult, skuDetailsList ->
            if (billingResult.responseCode == BillingClient.BillingResponseCode.OK) {
                if (skuDetailsList != null && skuDetailsList.size > 0) {
                    val flowParams = BillingFlowParams.newBuilder()
                        .setSkuDetails(skuDetailsList[0])
                        .build()
                    billingClient.launchBillingFlow(mContext as Activity, flowParams)
                } else {
                    //try to add item/product id "purchase" inside managed product in google play console
                    showMessage("Purchase Item not Found")
                }
            } else {
                showMessage(" Error " + billingResult.debugMessage)
            }
        }
    }

    /**
     * Verifies that the purchase was signed correctly for this developer's public key.
     *
     * Note: It's strongly recommended to perform such check on your backend since hackers can
     * replace this method with "constant true" if they decompile/rebuild your app.
     *
     */
    private fun verifyValidSignature(signedData: String, signature: String): Boolean {
        return try {
            // To get key go to Developer Console > Select your app > Development Tools > Services & APIs.
            val base64Key = mContext.getString(R.string.license_key)
            Security.verifyPurchase(base64Key, signedData, signature)
        } catch (e: IOException) {
            false
        }
    }

    fun handlePurchases(purchases: List<Purchase>) {
        for (purchase in purchases) {
            //if item is purchased
            if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PURCHASED) {
                if (!verifyValidSignature(purchase.originalJson, purchase.signature)) {
                    // Invalid purchase
                    // show error to user
                   showMessage("Invalid Purchase")
                    return
                }
//                 else purchase is valid
//                if item is purchased and not acknowledged
                if (!purchase.isAcknowledged) {
                    val acknowledgePurchaseParams = AcknowledgePurchaseParams.newBuilder()
                        .setPurchaseToken(purchase.purchaseToken)
                        .build()
                    billingClient.acknowledgePurchase(acknowledgePurchaseParams, ackPurchase)
                } else {
                    // Grant entitlement to the user on item purchase
                    // restart activity
                    if (!SharedPreferencesUtils.getPurchasedBillingValue(mContext)) {
                        SharedPreferencesUtils.setPurchasedBillingValue(mContext,true)
                        showMessage("Item Purchased")
                        (mContext as Activity).recreate()
                    }
                }
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.PENDING) {
                showMessage("Purchase is Pending. Please complete Transaction")
            } else if (mContext.getString(R.string.product_id) == purchase.skus[0] && purchase.purchaseState == Purchase.PurchaseState.UNSPECIFIED_STATE) {
                SharedPreferencesUtils.setPurchasedBillingValue(mContext,false)
                showMessage("Purchase Status Unknown")
            }
        }


    }


    private fun showMessage(message: String) {
        (mContext as Activity).runOnUiThread{
            Toast.makeText(mContext, message, Toast.LENGTH_SHORT).show()
        }

    }

    override fun onPurchasesUpdated(billingResult: BillingResult, purchases: MutableList<Purchase>?) {
        //if item newly purchased
        if (billingResult.responseCode == BillingClient.BillingResponseCode.OK && purchases != null) {
            handlePurchases(purchases)
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED) {
            val queryAlreadyPurchasesResult =
                billingClient.queryPurchases(BillingClient.SkuType.INAPP)
            val alreadyPurchases = queryAlreadyPurchasesResult.purchasesList
            alreadyPurchases?.let { handlePurchases(it) }
        } else if (billingResult.responseCode == BillingClient.BillingResponseCode.USER_CANCELED) {
            showMessage("Purchase Canceled")
        } else {
            showMessage("Error updated" + billingResult.debugMessage)
        }
    }


    fun onDestroyBilling() {
        billingClient.endConnection()
    }

}

import android.text.TextUtils
import android.util.Base64
import java.io.IOException
import java.security.*
import java.security.spec.InvalidKeySpecException
import java.security.spec.X509EncodedKeySpec

/**
 * Security-related methods. For a secure implementation, all of this code should be implemented on
 * a server that communicates with the application on the device.
 */
object Security {

    private const val KEY_FACTORY_ALGORITHM = "RSA"
    private const val SIGNATURE_ALGORITHM = "SHA1withRSA"

    /**
     * Verifies that the data was signed with the given signature, and returns the verified
     * purchase.
     * @param base64PublicKey the base64-encoded public key to use for verifying.
     * @param signedData the signed JSON string (signed, not encrypted)
     * @param signature the signature for the data, signed with the private key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun verifyPurchase(
        base64PublicKey: String, signedData: String,
        signature: String
    ): Boolean {
        if (TextUtils.isEmpty(signedData) || TextUtils.isEmpty(base64PublicKey)
            || TextUtils.isEmpty(signature)
        ) {
            //Purchase verification failed: missing data
            return false
        }
        val key = generatePublicKey(base64PublicKey)
        return verify(key, signedData, signature)
    }

    /**
     * Generates a PublicKey instance from a string containing the Base64-encoded public key.
     *
     * @param encodedPublicKey Base64-encoded public key
     * @throws IOException if encoding algorithm is not supported or key specification
     * is invalid
     */
    @Throws(IOException::class)
    fun generatePublicKey(encodedPublicKey: String): PublicKey {
        return try {
            val decodedKey = Base64.decode(encodedPublicKey, Base64.DEFAULT)
            val keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM)
            keyFactory.generatePublic(X509EncodedKeySpec(decodedKey))
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available.
            throw RuntimeException(e)
        } catch (e: InvalidKeySpecException) {
            val msg = "Invalid key specification: $e"
            throw IOException(msg)
        }
    }

    /**
     * Verifies that the signature from the server matches the computed signature on the data.
     * Returns true if the data is correctly signed.
     *
     * @param publicKey public key associated with the developer account
     * @param signedData signed data from server
     * @param signature server signature
     * @return true if the data and signature match
     */
    private fun verify(publicKey: PublicKey, signedData: String, signature: String): Boolean {
        val signatureBytes: ByteArray = try {
            Base64.decode(signature, Base64.DEFAULT)
        } catch (e: IllegalArgumentException) {
            //Base64 decoding failed
            return false
        }
        try {
            val signatureAlgorithm = Signature.getInstance(SIGNATURE_ALGORITHM)
            signatureAlgorithm.initVerify(publicKey)
            signatureAlgorithm.update(signedData.toByteArray())
            return signatureAlgorithm.verify(signatureBytes)
        } catch (e: NoSuchAlgorithmException) {
            // "RSA" is guaranteed to be available
            throw RuntimeException(e)
        } catch (e: InvalidKeyException) {
            //Invalid key specification
        } catch (e: SignatureException) {
            //Signature exception
        }
        return false
    }

}

var inAppPurchase: InAppPurchase  = InAppPurchase(this)
btnInApp.setOnClickListener {
            inAppPurchase.productPurchase()
        }