How to post JSON to PHP with curl

Question

I may be way off base, but I've been trying all afternoon to run the curl post command in this recess PHP framework tutorial. What I don't understand is how is PHP supposed to interpret my POST, it always comes up as an empty array.

curl -i -X POST -d '{"screencast":{"subject":"tools"}}'  \       http://localhost:3570/index.php/trainingServer/screencast.json 

(The slash in there is just to make me not look like an idiot, but I executed this from windows using PHP 5.2, also tried on a Linux server, same version with Linux curl)

There must be something I'm missing because it seems pretty straightforward, the post just isn't be interpreted right, if it was, everything would work great.

This is what I get back:

 HTTP/1.1 409 Conflict Date: Fri, 01 May 2009 22:03:00 GMT Server: Apache/2.2.8 (Win32) PHP/5.2.6 X-Powered-By: PHP/5.2.6 Transfer-Encoding: chunked Content-Type: text/html; charset=iso-8859-1  {"screencast":{"id":null,"subject":null,"body":null,          "dataUrl":null,"dataMedium":null,"createdOn":null,"author":null}} 

Answer 1

Normally the parameter -d is interpreted as form-encoded. You need the -H parameter:

curl -v -H "Content-Type: application/json" -X POST -d '{"screencast":{"subject":"tools"}}' \ http://localhost:3570/index.php/trainingServer/screencast.json 

Answer 2

Jordans analysis of why the $_POST-array isn't populated is correct. However, you can use

$data = file_get_contents("php://input"); 

to just retrieve the http body and handle it yourself. See PHP input/output streams.

From a protocol perspective this is actually more correct, since you're not really processing http multipart form data anyway. Also, use application/json as content-type when posting your request.