将HTTP标头“ User-Agent”添加到HTTP CONNECT请求

Question

Prerequisites

• Apache Tomcat 7
• Spring 3.2.11.RELEASE
• Apache Camel 2.14.1
• Camel HTTP4 Endpoint (camel-http4)

Problem

I try to call a https encrypted site via http4 component. The proxy which is in between my server and the internet (target server) checks the header "User-Agent" and rejects the request if it is empty.

The connect-Request does not contain the http header "User-Agent".

In org.apache.http.impl.execchain.MainClientExec in method private boolean createTunnelToTarget(AuthState proxyAuthState, HttpClientConnection managedConn, HttpRoute route, HttpRequest request, HttpClientContext context) throws HttpException, IOException following is called:

    BasicHttpRequest connect = new BasicHttpRequest("CONNECT", authority, request.getProtocolVersion());
    this.requestExecutor.preProcess(connect, this.proxyHttpProcessor, context);

this.requestExecutor.preProcess adds header "Host" and "Proxy-Connection" to the HTTP CONNECT request but not "User-Agent".

How can I add the Header "User-Agent" to the HTTP CONNECT request?

Regards,

Max

Answer 1

The problem is solved in httpclient 4.4.1.

In class org.apache.http.impl.client.HttpClientBuilder the httpprocessor is initialzed with a HttpRequestInterceptor for User-Agent:

    ClientExecChain execChain = createMainExec(
            requestExecCopy,
            connManagerCopy,
            reuseStrategyCopy,
            keepAliveStrategyCopy,
            new ImmutableHttpProcessor(new RequestTargetHost(), new RequestUserAgent(userAgentCopy)),
            targetAuthStrategyCopy,
            proxyAuthStrategyCopy,
            userTokenHandlerCopy);

The solution is to update the httpclient version from 4.3.3 to 4.4.1 . In maven I had to define the dependency so that not the verson used by camel was choosen.