Adding support to automatically set the auth token if google requests it

README.md

@@ -23,7 +23,7 @@ See [Google Client Login documentation][2] for details.
     var config = {
         user: '[email protected]',
         password: 'your-huge-very-very-strong-password',
-        source: 'yourCompany-yourMegaApp-version', 
+        source: 'com.company.app-name',
     };
     var c2dm = new C2DM(config);
 
@@ -39,19 +39,23 @@ See [C2DM documentation][3] for details.
 
     var message = {
         registration_id: 'Device registration id',
-        collapse_key: 'Collapse key',
+        collapse_key: 'Collapse key', // required
         'data.key1': 'value1',
         'data.key2': 'value2',
         delay_while_idle: '1' // remove if not needed
     };
 
     c2dm.send(message, function(err, messageId){
-
+        if (err) {
+            console.log("Something has gone wrong!");
+        } else {
+            console.log("Sent with message ID: ", messageId);
+        }
     });
 
 ### Avoiding login procedure
-You can avoid login procedure by manually setting Google ClientLogin Auth tokin in config for connection.
-First of all you need to get this token by executing next command after replacing `ROLE_EMAIL`, `ROLE_PASSWORDPASS` and `YOURCOMPANY-YOURAPP-Version` with your data:
+You can avoid the login procedure by manually setting Google ClientLogin Auth token in the connection config.
+First of all you need to fetch the token by executing the following command. Replace `ROLE_EMAIL`, `ROLE_PASSWORDPASS` and `YOURCOMPANY-YOURAPP-Version` with your data:
 
     $ curl -X POST https://www.google.com/accounts/ClientLogin -d Email=ROLE_EMAIL -d Passwd=ROLE_PASSWORDPASS -d accountType=HOSTED_OR_GOOGLE -d service=ac2dm -d source=YOURCOMPANY-YOURAPP-Version	
 
@@ -62,6 +66,34 @@ You will receive three lines. Skip `SID` and `LSID` and copy line starting with
     };
     var c2dm = new C2DM(config);
 
+However, Google will occaisionally require the token to be updated before further requests can be accepted. If this happens, the `Update-Client-Auth` header will automatically be used to update the current configurations token, but obviously will not be stored on the next reload. A `token` event will be triggered if this happens so you can update a local configuration file, but its probably easier to perform a login each time the application is started:
+
+    c2dm.on('token', function(err, token) {
+      // Do something with the new token
+    });
+
+### Testing sending a message
+If it looks like things aren't going your way, try sending a request manually using the following curl command and see what google sends back to you:
+
+    $ curl -H "Authorization: GoogleLogin auth=YOUR-LONG-TOKEN" -X POST https://android.apis.google.com/c2dm/send -d "registration_id=DESTINATION-TOKEN" -d "collapse_key=key" -d "data.event=hire" -v
+
+You should get back the header details along with a message id if sending has been successful. For example:
+
+    .... sending headers and SSL stuff .....
+    < HTTP/1.1 200 OK
+    < Content-Type: text/plain
+    < Date: Wed, 18 Jan 2012 11:18:01 GMT
+    < Expires: Wed, 18 Jan 2012 11:18:01 GMT
+    < Cache-Control: private, max-age=0
+    < X-Content-Type-Options: nosniff
+    < X-Frame-Options: SAMEORIGIN
+    < X-XSS-Protection: 1; mode=block
+    < Server: GSE
+    < Transfer-Encoding: chunked
+    <
+    id=0:1326885481081626%900b347100019e5f
+    .... more SSL stuff ....
+
 ### Keep-alive connection
 This module supports Connection: keep-alive header too keep connection to c2dm gate established. You could use it by simply including property in config:
 

lib/c2dm.js

@@ -29,6 +29,7 @@ function C2DM(config) {
         method: 'POST',
         headers: {}
     };
+    this.on('token', this.captureToken);
 }
 
 util.inherits(C2DM, emitter);
@@ -41,7 +42,6 @@ C2DM.prototype.captureToken = function(err, token) {
 
 C2DM.prototype.login = function(cb) {
     var self = this;
-    this.once('token', this.captureToken);
 
     if (cb) this.once('token', cb);
 
@@ -90,6 +90,15 @@ C2DM.prototype.send = function(packet, cb) {
 
     var request = https.request(this.c2dmOptions, function(res) {
         var data = '';
+
+        // Check if we need to update the headers and try again
+        var newToken = res.headers['update-client-auth'];
+        if (newToken) {
+            self.emit('token', null, newToken);
+            self.send(packet, cb);
+            return; // ignore any other events from this request
+        }
+
         function respond() {
             var idx = data.indexOf('id=');
             if (idx < 0) {