HttpRoutePlanner - How does it work with an HTTPS

问题:

I have an HTTPS proxy set up so that HTTP clients can send plain HTTP requests securely to the proxy. For example, a client can send an encrypted HTTP GET request to the proxy, which will remove the encryption and send the plain HTTP GET request to the end-site.

I learned that this is not a common set up and only Google Chrome has in-built features to support such a scenario. (Info here - http://wiki.squid-cache.org/Features/HTTPS#Encrypted_browser-Squid_connection). I have made Google Chrome work with my HTTPS proxy and hence there is no trouble on the proxy side.

I wish to write an HTTP Client that will encrypt all requests to my HTTPS Proxy. I tried setting an HTTPS proxy to DefaultHttpClient this way -

DefaultHttpClient dhc = new DefaultHttpClient();
HttpHost proxy = new HttpHost("192.168.2.3", 8181, "https"); //NOTE : https
dhc.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

Then trying to execute any request gives me an SSLPeerUnverifiedException. I do not understand the reason why.

During my exploration of the DefaultHttpClient API, I came across HttpRoutePlanner and HttpRoute with which we can specify whether the connection to proxies should be encrypted or not. However, I am unable to make this work.

Here is a diagram that explains my setup by differentiating it with a HTTP Proxy setup -

HTTP Proxy:

HTTP Client <------- Plain Text GET, POST Requests -------> HTTP Proxy <------- Plain Text GET, POST Requests -------> HTTP End-Site

HTTP Client <------- Plain Text CONNECT Requests -------> HTTP Proxy <------- Plain Text CONNECT Requests -------> HTTPS End-Site

NOTE: For HTTPS End-Sites, only the CONNECT Request is seen by the proxy. Then an SSL Tunnel is established between the Client and End-Site

HTTPS Proxy:

HTTP Client <------- Encrypted GET, POST Requests -------> HTTPS Proxy <-------- Plain Text GET, POST Requests -------->  HTTP End-Site

HTTP Client <------- Encrypted CONNECT Requests -------> HTTPS Proxy <------- Plain Text CONNECT Requests -------> HTTPS End-Site

NOTE: For HTTPS End-Sites, only the initial CONNECT Request should be encrypted to the proxy. The subsequent request will anyway be tunnelled.

Can anybody please let me know how I can achieve this goal? I believe HttpRoutePlanner should help, but I don't know how.

回答1:

I was able to make the Apache HttpClient 4.x work with the HTTPS proxy. The SSLPeerUnverifiedException that I mentioned in the question was thrown because I was not trusting the Proxy Server's certificate. Once this is taken care of, then connections to HTTPS End-Sites worked as expected.

For connections to HTTP end-sites, I had to use my own HttpRoutePlanner to make it work. Here's the code with the explanations -

DefaultHttpClient dhc = new DefaultHttpClient();
HttpHost proxy = new HttpHost("192.168.2.3", 8181, "https");
dhc.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

SchemeSocketFactory factory = null;
try {
    factory = new SSLSocketFactory(new SimpleTrustStrategy()); //Trust All strategy
} catch (GeneralSecurityException e1) {
    e1.printStackTrace();
}
Scheme https = new Scheme("https", 443, factory);
dhc.getConnectionManager().getSchemeRegistry().register(https);

HttpGet request = new HttpGet("http://en.wikipedia.org/wiki/Main_Page");    

try {
    HttpHost host = determineTarget(request);

    if(host.getSchemeName().equalsIgnoreCase("http")){
        dhc.setRoutePlanner(new MyRoutePlanner());
    }

} catch (ClientProtocolException e1) {
    e1.printStackTrace();
}

The implementation of MyRoutePlanner is below -

public class MyRoutePlanner implements HttpRoutePlanner {
    @Override
    public HttpRoute determineRoute(HttpHost target, HttpRequest request,
            HttpContext context) throws HttpException {
        return new HttpRoute(target, null
                , new HttpHost("192.168.2.3", 8181, "https")
                , true, TunnelType.PLAIN, LayerType.PLAIN); //Note: true
    }
}

To make the HttpClient talk to a HTTP End-site through an HTTPS Proxy, the route should be secure, but there should not be any Tunnelling or Layering.

回答2:

Apache HttpClient 4.x only supports SSL via proxy only by connection tunneling. It does not support HTTPS proxies.