storing contents of php://input in a variable - php

Question

I'm trying to edit and tweak someone else's REST server in PHP. It's based on the REST Server written by Phil Sturgeon. Pretty much got my head around all of it, but my requests aren't working as expected.
In the server constructor is the code
switch ($this->request->method)
{
case 'post':
$this->_post_args = $_POST;
$this->request->format and $this->request->body =
file_get_contents('php://input');
break;
}
I know that php://input can only be read once, so doing var_dump(file_get_contents('php://input')) before setting the variables shows that my XML data is being read correctly from the input stream but obviously the variables aren't set right.
But doing var_dump($this->request->body) only outputs NULL! Is there a special technique to storing the contents of php://input in a variable?
EDIT:
I'm using API Kitchen to send the POST request and the headers that it sends are
Status: 200
X-Powered-By: PHP/5.3.2-1ubuntu4.11
Server: Apache/2.2.14 (Ubuntu)
Content-Type: application/xml
Date: Fri, 10 Feb 2012 11:00:43 GMT
Keep-Alive: timeout=15, max=100
Content-Length: 936
Connection: Keep-Alive
I can't see from this what the encoding is.
EDIT 3:
The encoding is application/x-www-form-urlencoded which could be where the problem lies!! How do I specifically say what this should be?
EDIT 2:
$this->request->method contains 'post'

Answer 1

Thanks for all the help, it turns out that in order to work, the content type of the request must be application/xml, not application/x-www-form-urlencoded as it was.

Answer 2

if $this->request->format evaluates to false or NULL or 0, the later part of and operator does not execute.
$this->request->format and $this->request->body = file_get_contents('php://input');
^
|
+--- this part wont execute
You should have written it like
if($this->request->format){
$this->request->body = file_get_contents('php://input');
}
This helps in debugging.