Migration to Apache HttpClient 5.0 async APIs for HTTP/2 only

For those scenarios where HTTP/1.1 compatibility is no longer required HttpClient 5.0 provides CloseableHttpAsyncClient optimized for HTTP/2 protocol with full support for multiplexed request execution over a single HTTP/2 connection.

Migration steps

• Replace the default client builder with HTTP/2 specific one. Request and response handlers do not require any modification.

  Please note HTTP/2 clients do not have a connection manager. They maintain an internal map of active connections, one per distinct origin host. Therefore, TLS settings can be applied directly to the client instance, not a connection manager.

  Please note that presently HTTP/2 clients do not support request execution via an HTTP proxy.

  CloseableHttpAsyncClient client = HttpAsyncClients.customHttp2()
        .setTlsStrategy(ClientTlsStrategyBuilder.create()
                .setSslContext(SSLContexts.createSystemDefault())
                .setTlsVersions(TLS.V_1_3, TLS.V_1_2)
                .build())
        .setIOReactorConfig(IOReactorConfig.custom()
                .setSoTimeout(Timeout.ofSeconds(5))
                .build())
        .setDefaultRequestConfig(RequestConfig.custom()
                .setConnectTimeout(Timeout.ofSeconds(5))
                .setResponseTimeout(Timeout.ofSeconds(5))
                .setCookieSpec(StandardCookieSpec.STRICT)
                .build())
        .build();
  client.start();
  
  CookieStore cookieStore = new BasicCookieStore();
  
  CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
  
  HttpClientContext clientContext = HttpClientContext.create();
  clientContext.setCookieStore(cookieStore);
  clientContext.setCredentialsProvider(credentialsProvider);
  clientContext.setRequestConfig(RequestConfig.custom()
        .setConnectTimeout(Timeout.ofSeconds(10))
        .setResponseTimeout(Timeout.ofSeconds(10))
        .build());
  
  JsonFactory jsonFactory = new JsonFactory();
  ObjectMapper objectMapper = new ObjectMapper(jsonFactory);
  
  HttpRequest httpPost = BasicHttpRequests.post("https://nghttp2.org/httpbin/post");
  
  List<NameValuePair> requestData = Arrays.asList(
        new org.apache.http.message.BasicNameValuePair("name1", "value1"),
        new org.apache.http.message.BasicNameValuePair("name2", "value2"));
  
  Future<?> future = client.execute(
        JsonRequestProducers.create(httpPost, requestData, objectMapper),
        JsonResponseConsumers.create(jsonFactory),
        new FutureCallback<Message<HttpResponse, JsonNode>>() {
  
            @Override
            public void completed(Message<HttpResponse, JsonNode> message) {
                System.out.println(message.getBody());
            }
  
            @Override
            public void failed(Exception ex) {
                System.out.println("Error executing HTTP request: " + ex.getMessage());
            }
  
            @Override
            public void cancelled() {
                System.out.println("HTTP request execution cancelled");
            }
  
        });
  
  future.get();
  client.close(CloseMode.GRACEFUL);