blockchain | a bitcoin blockchain parser in Python | Blockchain library
kandi X-RAY | blockchain Summary
kandi X-RAY | blockchain Summary
a bitcoin blockchain parser in Python.
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Top functions reviewed by kandi - BETA
- Return an iterator over the blocks in the block
- Return the hash of the message
- Get a substring by length
- Parse block data
- Convert a public key to an address
- Hashes a given bytestring
- Convert bytestring to base58
- Convert ripemd160 to a base58 address
blockchain Key Features
blockchain Examples and Code Snippets
Community Discussions
Trending Discussions on blockchain
QUESTION
I am a newbie in Azure Blockchain development. I have a corporate MSDN subscription. Now I trying to create a blockchain member in my Azure Portal. After input all required values it shows a validation progress status. But after the successful validation 'Create' button not enabled. I have enough subscription amounts in my account.
Any help much appreciated.
...ANSWER
Answered 2021-Jun-15 at 02:55Form offical website, I find azure blockchain will be retired.
And I try to create it on portal and also try to create it by azure cli, all failed.
In conclusion:Azure recommends that users who have created a blockchain service provide the service and recommend that they migrate as soon as possible. For users who need to create this service, the service is not provided.
So this should be the willingness to fail to create success, you can raise a support ticket to confirm it.
QUESTION
I am currently running hyperledger fabric v2.2. I have developed the chaincode using the contractapi and developing the application using fabric-sdk-go/pkg/gateway
How can i get the transaction status and the transaction payload? I am aware of the GetHistoryByKey() which is available in the contractapi but that doesn't works out for my application.
I know there is hyperledger-explorer which can be used to search transactions by TxID but my use-case is my application will be querying by TxID and then it will verify the status of that particular transaction (TxID).
Also, i have tried to achieve this using the fabsdk but i am getting an error when i try to create instantiate the fabsdk using the fabsdk.New()
. There seems to be some compatibility issue with the connection-profile.json which i am using the fabric-sample project.
The error which i am getting is:
failed to create identity manager provider: failed to initialize identity manager for organization: MyOrgName: Either a cryptopath or an embedded list of users is required
The same connection-profile has been used in getting the network up and running, and everything seems to be working all good. I am able to submit and evaluate transactions.
SOLUTION
The system chaincodes are embedded in the peer itself. so we need to set the target otherwise it would just give the discovery error since the contract QSCC is not explicitly deployed on the channel.
Make sure to check the core.yaml file channel.system - the system chaincode should be enabled channel.system.qscc: enable
...ANSWER
Answered 2021-Jun-08 at 11:42Your client application can use the client SDK appropriate to your pogramming language to evaluate the GetTransactionByID
transaction function on the qscc
system chaincode, which is available on all peers. This transaction function takes a transaction ID as its only argument and returns a peer.ProcessedTransaction
protobuf, which contains the transaction envelope and a validation code.
QUESTION
We have a code in production that in some situation may left-shift a 32-bit unsigned integer by more than 31 bits. I know this is considered undefined behavior. Unfortunately we can't fix this right now, but we can work this around, if only we can assume how it works in practice.
On x86/amd64 I know processor for shifts uses only the appropriate less-significant bits of the shift count operand. So that a << b
is in fact equivalent to a << (b & 31)
. From the hardware design this makes perfect sense.
My question is: how does this work in practice on modern popular platforms, such as arm, mips, RISC and etc. I mean those that are actually used in modern PCs and mobile devices, not outdated or esoteric.
Can we assume that those behave the same way?
EDIT:
The code I'm talking about currently runs in a blockchain. It's less important how exactly it works, but at the very least we want to be sure that it yields identical results on all the machines. This is the most important, otherwise this can be exploited to induce a so-called chain split.
Fixing this means hassles, because the fix should be applied simultaneously to all the running machines, otherwise we are yet again at risk of the chain split. But we will do this at some point in an organized (controlled) manner.
Lesser problem with the variety of compilers. We only use GCC. I looked at the code with my own eyes, there's a
shl
instruction there. Frankly I don't expect it to be anything different given the context (shift operand comes from arbitrary source, can't be predicted at compile time).Please don't remind me that I "can't assume". I know this. My question is 100% practical. As I said, I know that on x86/amd64 the 32-bit shift instruction only takes 5 least significant bits of the bit count operand.
How does this behave on current modern architectures? We can also restrict the question to little-endian processors.
...ANSWER
Answered 2021-Jun-02 at 20:15With code that triggers undefined behavior, the compiler can just about do anything - well, that's why it's undefined - asking for a safe definition of undefined code doesn't make any sense. Theoretical evaluations or observing the compiler translating similar code or assumptions on what "common practice" might be won't really give you an answer.
Evaluating what a compiler really has translated your UB code to would probably be your only safe bet. If you want to be really sure what happens in the corner cases, have a look at the generated (assembly or machine) code. Modern debuggers give you the toolset to catch those corner cases and tell you what actually happens (the generated machine code is, after all, very well defined). This will be much simpler and much safer than to speculate on what code the compiler might probably emit.
QUESTION
Lets say i created an erc20 token. Now i want to make a smart contract that sends 1 coin to a user if they have X coins on another blockchain like bitcoin. Would that work? Can i read data from other blockchains using a cardano/ethereum/any other smart contract?
...ANSWER
Answered 2021-Jun-06 at 21:42There are some bridge applications that allow you to perform cross-chain operations (mostly run by exchanges). But these are operated on a different layer, unrelated to smart contracts.
What you're asking is not possible if you want to stick strictly to smart contracts.
However, you can use the oracle pattern. Create an off-chain app (the oracle) that listens to transactions from your contract to a specific address. Each transaction (from your contract to the target address) will trigger an action in the off-chain app - e.g. reading Bitcoin data. The oracle then sends another transaction to your smart contract, passing it the off-chain data.
QUESTION
When trying to run my program using gradle bootRun, the error shows that
Failed to apply plugin 'org.springframework.boot' Configuration with name 'runtime' not found
The following is my build.gradle
ANSWER
Answered 2021-Jun-06 at 16:02I assume you're using Gradle 7. In Gradle 7, the configurations compile
, testCompile
, runtime
and testRuntime
have been removed in favor of implementation
, testImplementation
, runtimeOnly
and testRuntimeOnly
. That's why Gradle issues
Failed to apply plugin 'org.springframework.boot' Configuration with name 'runtime' not found
To fix the issue, you should use the Gradle version that is supported by the Spring Boot Gradle Plugin version you're using (1.5.3, according to the snippet provided). The system requirements lists Gradle version 2 and 3 as requirement for Spring Boot 1.5.3. Everything thereafter is not supported.
QUESTION
Ive Been Trying to get an element from a page that Ive clicked on to get into the next page with soup.find_all. The problem is that it gives me the elements of the first page. Thanks in Advance.
The code:
...ANSWER
Answered 2021-Jun-06 at 08:45You have to increase the delay after clicking the next_page.click()
before content = driver.page_source.encode('utf-8').strip()
to make the page load a next page data.
It's not recommended to use hardcoded sleep.
Some better way to do it would to get data presented on the previous page and then use some kind of expected conditions to wait until the previous data no more presented.
QUESTION
I'm using Volley library to communicate with my API. I'm pretty new to Android and Kotlin and I'm really confused about extracting keys from the following JSON data
...ANSWER
Answered 2021-Jun-06 at 12:00I found it, I just used the getJSONObject()
method to make it work
QUESTION
I am trying to set up a Hyperledger Fabric Network with Hyperledger Explorer. I spin up a VM on the digital ocean cloud with ubuntu OS. From there, I spin up 3 orderers node, and 2 peers node. Which result in total of 5 nodes. (I am using RAFT setup).
However, I encounter the error as below when trying to start the hyperledger fabric explorer docker-container images.
Error: ...ANSWER
Answered 2021-Feb-20 at 23:54All configurations seems good, however you have to upgrade explorer version to be compatible with hyperledger fabric version.
So please use v1.1.4 instead of v1.1.1
Also make sure that you have mounted crypto config correctly, try to access this path inside the container /tmp/crypto/peerOrganizations/acme.com/tlsca/tlsca.acme.com-cert.pem
Try to change tlsCACerts
path to use peer tls ca.crt
/tmp/crypto/peerOrganizations/acme.com/peers/peer1.acme.com/tls/ca.crt
You have mentioned that the same configurations works with hyperledger fabric v2, if you have tried it locally not on the same server so I please disable the firewall on the server and give it a try
To check if you can reach domain and port please try this
cat > /dev/tcp/peer1.acme.com/7051
Check this https://support.bluemedora.com/s/article/Using-Bash-to-test-if-a-TCP-port-on-a-remote-system-is-open
QUESTION
Ive Been Trying to Click a Button on https://blockchain.coinmarketcap.com/chain/bitcoin But With No Success (Shown in photo below). I Couldn't even get the element I wanted to click. If someone can help me find the element and how to click it, it would be very helpful to me. Thanks in advance. The Button Im trying to click is the page 2 button
...ANSWER
Answered 2021-Jun-05 at 21:28First you need to wait until the element is presented on the page, then scroll to it and then click on it.
I tried to do it as following:
QUESTION
I'm new to Lisk blockchain technology and I am looking for some technical guidance of how the details of it looks like.
What is the preffered Lisk blockchain block size?
...ANSWER
Answered 2021-Jun-05 at 16:52Lisk SDK has a maximum block size of 30kb. The value is currently configurable between 10kb and 30kb.
Lisk HQ tested up to 100kb with success, so it's possible that later version will push those config boundaries.
You can always edit the config schema ( framework/src/schema/application_config_schema.ts ) in the SDK sources code to edit those values yourself ; but you must take into account the impact it has on the network : you may need to increase the block time, and set it to 15s instead of 10s for example.
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Install blockchain
You can use blockchain like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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