httpserver.h | Single header library for writing non | HTTP library

As your server (java side, live in localhost:8001) and client (xhttp side, live in somewhere else) are separated. The request is considered as cross origin requests (CORs).

There are 2 types of cross origin requests - Safe and unsafe:

• Only the below Content-Type are considered as SAFE in cross site request:
  • application/x-www-form-urlencoded
  • multipart/form-data
  • text/plain

So, application/json; is considered UNSAFE.

For safe request, there is not much restriction on server so you can get the response back while using application/x-www-form-urlencoded

• client <=> POST request <=> Server

For unsafe request, there is a preflight request (a special OPTIONS action) to ask the server

• if client origin is allowed and
• what can the client do

before making the real request, in your case the POST request.

1. client <=> pre-flight (OPTIONS) request <=> Server
2. client <=> POST request <=> Server

So the problem is there is no handling of preflight request and the request cannot be processed by server. To deal with it, you need to change your handler as follow:

So far I was able to think up FOUR options.

First Option:

You can do session management: set a cookie and next time check if it's set.

Set a cookie:

Does this anything to do with micrometer or is the question actually how to expose an HTTP endpoint in Java?

There are a lot of ways to do this, but since you are asking specifically for servlets:

• You need to create your own Servlet by extending HttpServlet and register it
• Here's a generic example to do it: A Simple Servlet Example – (write, deploy, run)
• Basically you need to send back what you get from prometheusRegistry.scrape()
• You can also take a look at MetricsServlet in Prometheus client
  (does not use Micrometer's PrometheusRegistry)

Also, let me leave this here as a general advice: always make sure that your InputStream/OutputStream/Reader/Writer/etc. is property closed (finally block or try-with-resource, in this case you will have a (Print)Writer).

The warning message there is a little bit misleading and technically should be error in this particular case as this is a breaking change in httpclinet library which can cause unexpected behavior of the program. This dependency itself comes as a transitive dependency from aws-java-sdk. So, to get it fixed just follow recommendation provided in the warning message and explicitly define the required version of httpclinet in your project pom file:

You are getting NoClassDefFoundError for com.sun.net.httpserver.HTTPHandler. Are you sure you have this in your packaged set of libraries?

The Eureka Server is implemented as Jersey REST endpoints in a web application. It can be deployed as a WAR on any servlet container: Tomcat, JBoss, Jetty, etc.

You can build the WAR from the code at https://github.com/Netflix/eureka/eureka-server.

But the Java HTTP Server you are using does not support the servlet API, so you can't just add the WAR to it.

• Option 1: run it as a separate process on a standalone Tomcat/Jetty/...
• Option 2: add an Embedded Tomcat or Jetty in your main class (like Spring Boot does).
• Option 3: try to figure out how to map the Jersey REST endpoints in your HTTP Server?

I had to send file content How can I serialize an input File object to JSON?

And it is able to read and save it using dcodestring How to parse data-uri in python?

Thank you all.

Modify the code to work with http.Handler instead of http.HandlerFunc.

There is no way to add/edit headers but we can use httpExchange.setAttribute() and httpExchange.getAttribute() methods to pass additional information when hopping between filters.

For adding headers to the request that we want to forward to service, we create a new http request from the original one and include attributes in headers