Not able to connect my app server to GCM's CCS using XMPPHP

Question

Like push-notification(downstream message), I want to implement upstream messaging from my android device to my app server in php. I am using this XMPPHP library from Github to connect my app server to GCM's CCS. But when I try to execute below code to connect GCM's CCS:

include 'XMPPHP/XMPP.php';
$conn = new XMPPHP_XMPP('gcm-preprod.googleapis.com', 5236, '<myProjectId>@gcm.googleapis.com', '<myApiKey>', 'xmpphp', 'http://myserverdomain', $printlog=true, $loglevel=XMPPHP_Log::LEVEL_INFO);
$conn->autoSubscribe();
$vcard_request = array();
try {
  $conn->connect();
...

I am getting following error.

1455354076 [INFO]: Connecting to tls://gcm-preprod.googleapis.com:5236 1455354106 [ERROR]: Could not connect. Could not connect before timeout.

Answer 1

How CCM will know about where(which app server) to send the upstream message? As there is no explanation in provided documentation.

I think you missed the part in the documentation where it says:

To initiate an upstream message, the client app sends a request containing the following:

• The address of the receiving app server, in the format [email protected].
• A message ID that should be unique per sender ID.
• The message data comprising the key/value pairs of the message's payload.

You need to specify the SENDER_ID to know which server you are sending to. Sender ID is a project number acquired from the API console

How to handle the upstream message in PHP? As I am using PHP in backend.

This thread might help you. Read the comments in the accepted answer.

It says that in order to use PHP you need to look for a library that supports XMPP protocol.