ESP8266 Community Forum

I was looking into a solution to send push notifications from an ESP8266 module to an Android application. I know that this is possible with the Google Cloud Messaging service.

But what I found on the internet is using an external webserver, able to run PHP (or Python) scripts and using a MySQL server to store registration IDs.

So far so good, but why do I need to setup an external server with MySQL and PHP just to send messages to the Android devices. The ESP8266 has server capabilities build-in and has enough storage to save registration IDs in the Flash memory.
What I wanted is:


As I could not find any tutorial or example on the Internet how to achieve this, I started to write the code by myself.
And here is the result:
ESP8266 - Google Cloud Messaging without external server
Of course the code is open source and stored in my Github repository

Hope it helps someone.

Hi,

Very nice, thank you.
Seems really promissing. I will try it soon

JP

Hi JP, I saw your comment on my website:

freedom2000 wrote:Fantastic tutorial.

I have got it work, but have been obliged to increase the DeviceId to 162

if (newDeviceID.length() != 162) {

140 seems to be no longer supported by Google ?

However it works now.
I can hadle the message intent in my Android App following Basic4Android tutorial here : https://www.b4x.com/android/forum/threa ... ork.35635/

I have also seen that it should be possible to directly send a notification to the device :

Here is a JSON-formatted message can containing both notification and data:

{
“to” : “APA91bHun4MxP5egoKMwt2KZFBaFUH-1RYqx…”,
“notification” : {
“body” : “great match!”,
“title” : “Portugal vs. Denmark”,
“icon” : “myicon”
},
“data” : {
“Nick” : “Mario”,
“Room” : “PortugalVSDenmark”
}
}

But I am not tottally “fluent” with your code and Json…
so I don’t know where to add thes “notification” key.

I believe it should be somewhere here :
void loop() {
// Handle new client request on HTTP server if available
WiFiClient client = server.available();
if (client) {
webServer(client);
}

if (doPush) {
doPush = false;
// Create messages & keys as JSON arrays
DynamicJsonBuffer jsonBufferKeys;
DynamicJsonBuffer jsonBufferMsgs;
JsonArray& msgKeysJSON = jsonBufferKeys.createArray();
JsonArray& msgsJSON = jsonBufferMsgs.createArray();
char buf[4];
char msgOne[24] = “Test message number “;
itoa(msgCnt,buf,10);
strcat(msgOne,buf);
msgKeysJSON.add(“message”);
msgKeysJSON.add(“timestamp”);
msgsJSON.add(msgOne);
msgsJSON.add(buf);
gcmSendMsg(msgKeysJSON, msgsJSON);
msgCnt++;
}

Any help please ?
Thanks
JP

In case you didn't get my reply there:

Hello JP,

To create the message with both data and notification you can do like following:

Code: Select all      /***********************************************
       Create JSON object to send GCM with data and notification
      ***********************************************/
      /* This is the GCM message example:   
         {
            “to” : “APA91bHun4MxP5egoKMwt2KZFBaFUH-1RYqx…”,
            “notification” : {
               “body” : “great match!”,
               “title” : “Portugal vs. Denmark”,
               “icon” : “myicon”
            },
            “data” : {
               “Nick” : “Mario”,
               “Room” : “PortugalVSDenmark”
            }
         }
      */

      /** Buffer for Json object with complete GCM message */
      DynamicJsonBuffer jsonBuffer;
      /** Buffer for Json object with data */
      DynamicJsonBuffer jsonDataBuffer;
      /** Buffer for Json object with notification */
      DynamicJsonBuffer jsonNotifBuffer;

      // Prepare "data" object
      JsonObject& dataJSON = jsonDataBuffer.createObject();
      dataJSON["Nick"] = "Mario";
      dataJSON["Room"] = "PortugalVSDenmark";
      
      // Prepare "notification" object
      JsonObject& notifJSON = jsonNotifBuffer.createObject();
      notifJSON["body"] = "great match!";
      notifJSON["title"] = "Portugal vs. Denmark";
      notifJSON["icon"] = "myicon";
      
      // Prepare GCM JSON object
      JsonObject& msgJSON = jsonBuffer.createObject();

      // Add the device ID you want to push a message to
      msgJSON["to"] = "YourAndroidMessageIDHere";; // put your Android device ID here
      
      // Add the notification data to the message
      msgJSON["notification"] = notifJSON;
      
      // Add the data to the message
      msgJSON["data"] = dataJSON;
      
      // Convert the JSON to a String
      String gcmMessage;
      msgJSON.printTo(gcmMessage);

      // Just for testing, print out the message on serial port
      Serial.println("GCM message as JSON");
      msgJSON.prettyPrintTo(Serial);
      Serial.println("");
      
      // Send the message by calling gcmSendOut instead of gcmSendMsg !!!!
      gcmSendOut(gcmMessage);


Here is the debug output from serial port:

Code: Select allGCM message as JSON
{
  "to": "APA91bG27MAZZpfiWsA..............",
  "notification": {
    "body": "great match!",
    "title": "Portugal vs. Denmark",
    "icon": "myicon"
  },
  "data": {
    "Nick": "Mario",
    "Room": "PortugalVSDenmark"
  }
}
Connecting to http://android.googleapis.com
Connected to GCM server
This is the Request to http://android.googleapis.com :
POST /gcm/send HTTP/1.1
Host: android.googleapis.com
Accept: */*
Authorization: key=AIzaSyAuzBZpPRzI...................
Content-Type: application/json
Content-Length: 286

{"to":"APA91bG27MAZZpfiWsAISmulOO.........................................","notification":{"body":"great match!","title":"Portugal vs. Denmark","icon":"myicon"},"data":{"Nick":"Mario","Room":"PortugalVSDenmark"}}


Response from GCM server:
Found JSON result: {"multicast_id":7921150450792951525,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1460270944874316%a03653e3f9fd7ecd"}]}


Message successfully sent!!!!!!!!!!!!!!!!!!!!!!!!!!!

And on my Android tablet I received:

Code: Select all04-10 15:25:04.520 3775-20569/tk.giesecke.myhomecontrol D/MHC-GCM: Got GCM = Bundle[{gcm.notification.title=Portugal vs. Denmark, Nick=Mario, Room=PortugalVSDenmark, from=928633261430, gcm.notification.body=great match!, gcm.notification.icon=myicon, android.support.content.wakelockid=1061, collapse_key=do_not_collapse}]


Hope this helps for your specific question.

Hi,

You are simply THE BOSS

That was what exactly what I was looking for.
I will try right now

Many thanks
JP