Using Apache HTTPClient - how can one see the raw request string before it's being sent?

Question

For debugging purposes, I'd like to see the raw request that is going to be sent. Is there a way to get this without a HTTP monitor directly from the API of HttpPost or HttpClient?

I found some "almost" duplicate questions, but not for this particular one

Answer 1

You can set some environment variables for Apache HttpClient (example tested for 4.3.2).

System.setProperty("org.apache.commons.logging.Log","org.apache.commons.logging.impl.SimpleLog");
System.setProperty("org.apache.commons.logging.simplelog.showdatetime", "true");
System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http.wire", "DEBUG");

There are also some more variables for debugging:

System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http.impl.conn", "DEBUG");
System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http.impl.client", "DEBUG");
System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http.client", "DEBUG");
System.setProperty("org.apache.commons.logging.simplelog.log.org.apache.http", "DEBUG");

Answer 2

Try this:

HttpClient client = new HttpClient();
PostMethod method = new PostMethod(url);

method.setParameter(...., ....);

to retrieve the URI

System.out.println("getUri: " + method.getURI());

to retrieve the parameters in POST

method.getRequestEntity().writeRequest(System.out);

Answer 3

org.apache.http.client.fluent.Request#viaProxy 

This method can make your request pass through proxy server, so your can launch a local proxy server, for example Fiddler, so this debugging proxy can show the details of http request and response.

Answer 4

Try enabling DEBUG mode in your logging configurations, if you're using log4j you can add this to the log4j.xml file of your project

<root>
    <priority value="DEBUG" />
    <appender-ref ref="FILE" />
</root>

You will have the full request headers, params, body, etc, logged in your logs files.