private void createTunnel()

in httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AsyncConnectExec.java [368:433]
51 lines of code
6 McCabe index (conditional complexity)

    private void createTunnel(
            final State state,
            final HttpHost proxy,
            final HttpHost nextHop,
            final AsyncExecChain.Scope scope,
            final AsyncExecChain chain,
            final AsyncExecCallback asyncExecCallback) throws HttpException, IOException {

        final HttpClientContext clientContext = scope.clientContext;

        final AuthExchange proxyAuthExchange = proxy != null ? clientContext.getAuthExchange(proxy) : new AuthExchange();

        if (authCacheKeeper != null) {
            authCacheKeeper.loadPreemptively(proxy, null, proxyAuthExchange, clientContext);
        }

        final HttpRequest connect = new BasicHttpRequest(Method.CONNECT, nextHop, nextHop.toHostString());
        connect.setVersion(HttpVersion.HTTP_1_1);

        proxyHttpProcessor.process(connect, null, clientContext);
        authenticator.addAuthResponse(proxy, ChallengeType.PROXY, connect, proxyAuthExchange, clientContext);

        chain.proceed(connect, null, scope, new AsyncExecCallback() {

            @Override
            public AsyncDataConsumer handleResponse(
                    final HttpResponse response,
                    final EntityDetails entityDetails) throws HttpException, IOException {

                clientContext.setAttribute(HttpCoreContext.HTTP_RESPONSE, response);
                proxyHttpProcessor.process(response, entityDetails, clientContext);

                final int status = response.getCode();
                if (status < HttpStatus.SC_SUCCESS) {
                    throw new HttpException("Unexpected response to CONNECT request: " + new StatusLine(response));
                }

                if (needAuthentication(proxyAuthExchange, proxy, response, clientContext)) {
                    state.challenged = true;
                    return null;
                }
                state.challenged = false;
                if (status >= HttpStatus.SC_REDIRECTION) {
                    state.tunnelRefused = true;
                    return asyncExecCallback.handleResponse(response, entityDetails);
                }
                return null;
            }

            @Override
            public void handleInformationResponse(final HttpResponse response) throws HttpException, IOException {
            }

            @Override
            public void completed() {
                asyncExecCallback.completed();
            }

            @Override
            public void failed(final Exception cause) {
                asyncExecCallback.failed(cause);
            }

        });

    }