I am trying to connect my common lisp application to a Drupal driven server site using http-post and I am having trouble debugging my request. When I use the Firefox plugin Poster to make the request everything works fine but when I make the request from inside my common lisp application I get incorrect behavior. I would really like to see the http-request produced by Poster but it seems to have no option for this, is there another little app that is similar but would show me the actual Request? Or is there someway to get this out of Poster.
It sounds like you could use a debugging HTTP proxy. Some suggestions in HTTP debugging proxy for Linux and Mac.
You could also use Wireshark.
As for the Common Lisp part, what library are you using? Are you logging in first? If using Drakma, are you using a cookie jar to pass the session cookies from one request to the other? (see the examples on the documentation page, search for (make-instance 'cookie-jar))