$_POST undefined from remote server POST

I am writing a Drupal 7 module which is listening for HTTP POST messages to be sent by a 3rd party remote application. For testing I am sending messages using the Firefox Poster extension.

If I POST the message, the following code fails to place any value in my local vars (I get 'undefined index'):

$transId = urldecode($_POST['c2s_transaction_id']);

However, if I send the message using GET, the vars get populated fine with the following code:

$transId = urldecode($_REQUEST['c2s_transaction_id']);

This is true on both my local WAMP setup and on a shared hosting package.

I have never worked with HTTP POST messages before and have开发者_运维技巧 no idea where the problem might be. Could it be Drupal, the web server, or my code? Can anyone suggest how I might resolve this?

Many thanks,

Polly

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Drupal removes the $_POST/$_GET in the system, just use $_REQUEST instead.