Apache HttpClient reuse connections only within the same HttpContext

Question

How do I create a ConnectionReuseStrategy that only reuses connections within the same HttpContext.

e.g. When executing a request in a HttpContext, there may be a redirect to an external domain and back that creates a new connection for the external domain, and reuses the first connection to the original domain when it returns.

However once I'm finished with this HttpContext, and I execute the same request in a new HttpContext, it should not reuse the connections even though the domains are the same. I cannot manually close all connections in the HttpClient since there are parallel HttpContext threads running and they should not reuse each others connections.

Answer 1

You could leverage HttpClient ability to maintain stateful connections [1]

One can either manually manage user identity by setting a user token uniquely identifying a particular user in the execution context

HttpClientContext context = HttpClientContext.create();
context.setUserToken("user 1");

Or use a custom user token handler to do it automatically for all requests.

This code snippet demonstrates how one can use thread id to make HttpClient re-use persistent connections only when created by the same thread.

UserTokenHandler userTokenHandler = new UserTokenHandler() {

    @Override
    public Object getUserToken(final HttpContext context) {
        return Thread.currentThread().getId();
    }

};

CloseableHttpClient client = HttpClients.custom()
        .setUserTokenHandler(userTokenHandler)
        .build();

[1] http://hc.apache.org/httpcomponents-client-4.3.x/tutorial/html/advanced.html#stateful_conn