GCM(2)GCM Demo Application

GCM(2)GCM Demo Application

This demo consists of the following pieces:

1. A web server containing a page where you can send messages

2. An Android application that receives and displays such messages.



Setting Up GCM in the GCM(1) blog.



Setting Up the Server
…snip...



Using App Engine for Java
Long time since I last play with app engine, https://appengine.google.com.



1. From the SDK Manager, install Extras> Google Cloud Messaging for Android Library



2. The sample project is under this directory

/opt/android-sdk/extras/google/gcm/samples/gcm-demo-appengine





Setting Up the Device
The client demo is here.

/opt/android-sdk/extras/google/gcm/samples/gcm-demo-client





Error Message:
[C2DMReg] handleRequest caught javax.net.ssl.SSLException: Not trusted server certificate



javax.net.ssl.SSLException: Not trusted server certificate

at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.startHandshacke

at android.net.SSLCertificateSocketFactory.verifyHostname



Error Message:
Intent service name: GCMIntentService-1044806436104-1

GCMRegistrar internal error: retry receiver class not set yet.

GCMBaseIntentService handleRegistration: registrationId = null, error = SERVICE_NOT_AVAILABLE, unregistered = null



Solution:
The problem is not code related, but link to the test phone. The test phone do not have a SIM, and the clock was not set. There is a wrong time there.



Error Message on Server Side:
com.google.android.gcm.demo.server.SendMessageServlet sendSingleMessage: Exception posting Message()
com.google.android.gcm.server.InvalidRequestException: HTTP Status Code: 401
at com.google.android.gcm.server.Sender.sendNoRetry(Sender.java:177)
at com.google.android.gcm.demo.server.SendMessageServlet.sendSingleMessage(SendMessageServlet.java:88)
at com.google.android.gcm.demo.server.SendMessageServlet.doPost(SendMessageServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:102)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:266)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:146)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:447)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:454)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:461)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:703)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:338)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:330)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:458)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
  at java.lang.Thread.run(Thread.java:679)



Solution:
It store an old wrong key in the database, just delete it and replace with this new key.

Key for server apps (with IP locking).





Error Message while I am using the emulator:
java.lang.unsupportedoperationexception device does not have package com.google.android.gsf



Solution:
The virtual device I create has no GOOGLE API support. I will create another AVD.



I made the demo works in my own projects 4mymessage and EasyRestClientAndroid.



And I change some point from the original example:



1. That is the content sent by server side

Message message = new Message.Builder().addData("message",
"Message I want you to know.").build();



I change the Message.Builder to carry some customized message, and this message can be replaced by my business logic part.


2. How to receive and display the customized message
On the client side
protected void onMessage(Context context, Intent intent) {
     Log.i(TAG, "Received message");
     String message = getString(R.string.gcm_message);

     String extra_message = intent.getStringExtra("message");
     message = message + extra_message;

     displayMessage(context, message);
     // notifies user
     generateNotification(context, message);
}



We can get the message from getStringExtra method.


References:
https://developer.android.com/google/gcm/demo.html



http://sillycat.iteye.com/blog/586786

http://sillycat.iteye.com/blog/586787

http://sillycat.iteye.com/blog/770453

http://sillycat.iteye.com/blog/774529

http://sillycat.iteye.com/blog/774534

http://sillycat.iteye.com/blog/772524



http://www.techques.com/question/1-5104500/javax.net.ssl.SSLHandshakeException:-Could-not-verify-SSL-certificate-for:-https:--android.apis.google.com-c2dm-send



http://stackoverflow.com/questions/2642777/trusting-all-certificates-using-httpclient-over-https



http://stackoverflow.com/questions/2012497/accepting-a-certificate-for-https-on-android



http://androidmyway.wordpress.com/2012/07/09/gcm-demo/



http://stackoverflow.com/questions/11398470/google-cloud-messaging-gcm-service-not-available



http://android.amolgupta.in/2012/07/google-cloud-messaging-gcm-tutorial.html



http://stackoverflow.com/questions/11339445/com-google-android-gsf-package-couldnt-be-found