Question

I can’t work out how you pass arguments to an http post request with trivial-http library. I can make a post but I’m not sure how to pass post variables. as a character stream.

http://common-lisp.net/project/trivial-http/user-guide.html#http-post

Answer 1

You need to pass the post variables in as the content of the post request. The most common way is as application/x-www-form-urlencoded, though multipart/form-data can be used if you need to do file uploads; see here for details on the encodings.

To pass information in a POST request using application/x-www-form-urlencoded, you need to pass that in as the content type, and a url-encoded query string as the content. Something like this should work:

(thttp:http-post 'http://example.com/submit-form' 'application/x-www-form-urlencoded'                  'foo=bar&baz=quux') 

If you need to escape strings that will be passed in as keys or values for the POST requests, then you can use escape-url-query to escape them to be safe to pass in in a url-encoded body:

(thttp:http-post 'http://example.com/submit-form' 'application/x-www-form-urlencoded'                  (format nil 'foo=~a&bar=~a' (thttp:escape-url-query foo)                                               (thttp:escape-url-query bar))))