Connecting to GCM server running at local server

Question

I am working on push notifications with Google Cloud Messaging(GCM). I am able to setup server and client side following this tutorial.

The server runs on Apache Tomcat6.0 (localhost) and Android emulator on Google APIs (API level 17). I have a sender id and API key. When run from the emulator, I get a successful device connection message. Sooner after that, upon sending message from server shows the following error.

com.google.android.gcm.server.InvalidRequestException: HTTP Status Code: 401()
com.google.android.gcm.server.Sender.sendNoRetry(Sender.java:211)
com.google.android.gcm.server.Sender.send(Sender.java:125)
com.google.android.gcm.demo.server.SendAllMessagesServlet.doPost(SendAllMessagesServlet.java:83)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

From other posts, I understand wrong API key is the culprit. But in my case, I made sure I am using the right one from the API console.

By the way, when I run the emulator, I saw a message 'sending regId to server'. What is the registration id? It is not same as sender id; looks like an encoded one.

Any break through?

EDIT

The issue is finally solved! Ant was not properly building the WAR file. So API key hardly gets updated. It was hell of a nightmare to spot the bug. Thanks all for the inputs!

Answer 1

I suggest you to read the GCM guide:

GCM guide for Android

The sender ID is a constant that is going to be used in the comunication between GCM and your server. The regsitratiomID (regID) is managed by the GCM service when your phone registers to his service.

A better definition: http://developer.android.com/google/gcm/gcm.html

Sender ID:

A project number you acquire from the API console, as described in Getting Started. The sender ID is used in the registration process to identify an Android application that is permitted to send messages to the device.

Registration ID:

An ID issued by the GCM servers to the Android application that allows it to receive messages. Once the Android application has the registration ID, it sends it to the 3rd-party application server, which uses it to identify each device that has registered to receive messages for a given Android application. In other words, a registration ID is tied to a particular Android application running on a particular device.