Java implementation HTTP Proxy (4)

Next, we'll focus on dispatcher because this class is the key to implementation
The following method completes forwarding, which is the HttpRequest
First we created a socket based on the specified host and port. The socket is connected to the real host
and then we call the request method, which forwards the request, which is simpler, simply by writing the header to the outputstream of the socket.
Step Three, we use the Httpresponsefactory read method to read and encapsulate a HttpResponse object from the InputStream of the socket.
Step Fourth, both the response header and the response stream are written to the client. The client's outputstream can be obtained from the HttpRequest object.
   

    /** * @param request-void */public void dispatch (HttpRequest request, httpresponse response, Proxyhos
        T proxyhost) {String host = Proxyhost.gethost ();
        int port = Proxyhost.getport ();

        Socket socket = NULL;
            try {socket = This.createsocket (host, Port);
            Socket.setsotimeout (10000);
            Socket.setkeepalive (FALSE);
            InputStream Socketinputstream = Socket.getinputstream ();

            OutputStream Socketoutputstream = Socket.getoutputstream (); if (logger.isdebugenabled ()) {//Logger.debug ("------------------request.header\r\n" + reques
            T.tostring ());
            This.request (Request, Socketoutputstream);

            HttpResponse HttpResponse = Httpconnectionfactory.createhttpresponse (Socketinputstream, SocketOutputStream); if (HttpResponse!= null) {Response.sethttpheader (httpResponse.gethttpheader (). Clone ());
                Response.setchunked (httpresponse.getchunked ());
                Response.setcontenttype (Httpresponse.getcontenttype ());
                Response.setstatus (Httpresponse.getstatus ());
                Response.setreasonphrase (Httpresponse.getreasonphrase ());
                This.resonse (Request, HttpResponse, Request.getoutputstream ());
            Response.setcontentlength (Httpresponse.getcontentlength ()); The catch (IOException e) {if (logger.iserrorenabled ()) {L
            Ogger.error (Request.getrequesturl (), E);
                    } finally {if (socket!= null) {try {
                Socket.close (); The catch (IOException e) {}}}}

Here is the request method:
1. First, we need to modify the HTTP request header, mainly to modify the request host and port number, otherwise the server will think that the request is not itself, because the client sent the request is to our agent request, and in fact we are just a proxy, so we need to modify it, and send it to the real host.
2. Will request the hair to the service period, only is writes the request header string to the OutputStream inside.

3. Send the client's other request data to the server, such as POST request or upload file. But different requests send the data is not the same, so our program must be able to know how much data the client sent, we use Contentpump.pumpcontentstream () This method to send the request data to the server, it is like a pump, Draw the data in a pipe into another pipe. But it must know beforehand how much to smoke, otherwise, blocking IO will be blocked when the data is read to the end.

    /** * @param request * @param outputstream * @throws ioexception/private void request (HttpR Equest request, OutputStream OutputStream) throws IOException {String host = Inetaddress.getlocalhost (). Getho

        Staddress ();
    
            if (usexforwardedfor) {String xforwardedfor = Request.getheader ("X-forwarded-for");
            if (xforwardedfor = = null) {xforwardedfor = host;
            else {xforwardedfor = "," + host; }//Local:not set HTTP_CLIENT_IP request.setheader ("Http_client_ip", request.getremoteaddr
            ());
        Request.setheader ("X-forwarded-for", xforwardedfor);
        String headers = request.tostring ();
        Outputstream.write (Headers.getbytes ());
        Outputstream.flush ();
    Httpstream.pipe (Request.getinputstream (), OutputStream, Request.getcontentlength ()); }