While trying to figure out how a service worked I recently had to put together a Java class that let you easily replay a http conversation which had been sniffed.

I got bored of using telnet while making small changes to the payload and curl wants requests converted into an XML format it appears.

This simple socket based class lets you send a captured http request to a service. I've removed the exception handling for brevity.

import java.io.*;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket(args[0], 80);
        
        BufferedWriter out = new BufferedWriter(
                new OutputStreamWriter(socket.getOutputStream(), "UTF8"));
        BufferedReader in = new BufferedReader(
                new InputStreamReader(socket.getInputStream()));
                
        sendMessage(out, new File(args[1]));
        readResponse(in);
        
        out.close();
        in.close();
    }
    
    private static void sendMessage(BufferedWriter out, File request) throws IOException {<br />
        System.out.println(" * Request");
        
        for (String line : getContents(request)) {
            System.out.println(line);
            out.write(line + "\r\n");
        }
        
        out.write("\r\n");
        out.flush();
    }
    
    private static void readResponse(BufferedReader in) throws IOException {
        System.out.println("\n * Response");
        
        String line;
        while ((line = in.readLine()) != null) {
            System.out.println(line);
        }
    }
    
    private static List<String> getContents(File file) throws IOException {
        List<String> contents = new ArrayList<String>();
        
        BufferedReader input = new BufferedReader(new FileReader(file));
        String line;
        while ((line = input.readLine()) != null) {
            contents.add(line);
        }
        input.close();
        
        return contents;
    }
}

For example. Running this class with the parameters: "google.co.uk /path/to/stored/file" with the stored file being just:

GET /intl/en/policies/privacy/ HTTP/1.1

Will give you this output:

 * Sending
GET /intl/en/policies/privacy/ HTTP/1.1

* Response
HTTP/1.1 200 OK
Vary: Accept-Encoding
Content-Type: text/html
Last-Modified: Fri, 27 Jan 2012 17:53:03 GMT
Date: Tue, 07 Feb 2012 21:40:30 GMT
Expires: Tue, 07 Feb 2012 21:40:30 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
Server: sffe
X-XSS-Protection: 1; mode=block
Transfer-Encoding: chunked

// Body content of web page
<!DOCTYPE html

For capturing payloads I recommend using tcpflow running on the target host as "tcpflow port 80"