[jetty-dev] Tracking Ajax requests/responses with Jetty ProxyServlet

[Gilles Ducret <gilles.ducret@xxxxxxxxx>]

Hi,

I have created a ProxyServlet to intercept the Ajax JSON request of a third party tool we have acquired in the company.

My objective is to modify some of the response on the fly.

I hav a first issue, that is I can't intercept the json calls, can't track them. They go through the proxy (when the proxy is done the browser displays an error message), but I see no traces of them (neither in service, nor in onresponsecontent, nor in onresponsesuccess).

My code for this proxy servlet is as follow

public class MyProxy extends ProxyServlet {

 

private int count = 0;

private final Charset CHARSET = Charset.forName("ISO-8859-1");

    @Override

    public void init(ServletConfig config) throws ServletException {

      super.init(config);

      System.out.println("init done !");

    }

    

    private void displayRequest(HttpServletRequest request) throws IOException {

    

    if (request == null)

    return;

    

    System.out.println("--- Request ---");

    System.out.println("Content type: " + request.getContentType());

    System.out.println("Remote address: " + request.getRemoteAddr());

    System.out.println(request.getQueryString());

    

    Enumeration<String> headernames = request.getHeaderNames();

    while(headernames.hasMoreElements()) {

    String headerName = headernames.nextElement();

    System.out.println("Header " + headerName + ": " + request.getHeader(headerName));

    }    

    // Attributes

    Enumeration<String> atttributesNames = request.getAttributeNames();

    while(atttributesNames.hasMoreElements()) {

    String attributeName = atttributesNames.nextElement();

    System.out.println("Attribute " + attributeName + ": " + request.getAttribute(attributeName));

    }

    // Parameters

        Enumeration<String> parameterNames = request.getParameterNames();

        while (parameterNames.hasMoreElements()) {

            String paramName = parameterNames.nextElement();

            System.out.print("Parameter " + paramName + ":");

            String[] paramValues = request.getParameterValues(paramName);

            for (int i = 0; i < paramValues.length; i++) {

                String paramValue = paramValues[i];

                System.out.print(paramValue + ";");

            }

        }

        

        System.out.println("--- End Request ---");

    }

@Override

protected void service(HttpServletRequest arg0, HttpServletResponse arg1)

throws ServletException, IOException {

    System.out.println("Servicing (" +  count++ + ")");

displayRequest(arg0);

super.service(arg0, arg1);

}

@Override

protected void onResponseContent(HttpServletRequest request,

HttpServletResponse response, Response proxyResponse,

byte[] buffer, int offset, int length) throws IOException {

//System.out.write(buffer, offset, length);

System.out.println("--- onResponseContent ---" + getRequestId(request));

// This is where I'd like to print the buffer, because this is what is going to be modified by COEOS

super.onResponseContent(request, response, proxyResponse, buffer, offset,

length);

}

@Override

protected void onResponseSuccess(HttpServletRequest request,

HttpServletResponse response, Response proxyResponse) {

// TODO Auto-generated method stub

System.out.println("--- onResponseSuccess ---" + getRequestId(request));

super.onResponseSuccess(request, response, proxyResponse);

}

    

    

}

Any idea of what is wrong?

Then I have a second issue. The response content can be sent is several chunk. How can i modify the content in such case?

Thanks for your help

Gilles