Develop Reference

How to use FCM notification with blogger using retrofit

I looking for the way to setup FCM Server Protocol if there's no hosting/own server Managed by google like blogger template's, and setup the dependencies on project.
I see in this question. some answers contains code similar to retrofit codes using "okhttp3"
String SCOPE = "https://www.googleapis.com/auth/firebase.messaging";
String FCM_ENDPOINT
= "https://fcm.googleapis.com/v1/projects/zoftino-stores/messages:send";
GoogleCredential googleCredential = GoogleCredential
.fromStream(new FileInputStream("firebase-private-key.json"))
.createScoped(Arrays.asList(SCOPE));
googleCredential.refreshToken();
String token = googleCredential.getAccessToken();
final MediaType mediaType = MediaType.parse("application/json");
OkHttpClient httpClient = new OkHttpClient();
Request request = new Request.Builder()
.url(FCM_ENDPOINT)
.addHeader("Content-Type", "application/json; UTF-8")
.addHeader("Authorization", "Bearer " + token)
.post(RequestBody.create(mediaType, jsonMessage))
.build();
Response response = httpClient.newCall(request).execute();
if (response.isSuccessful()) {
log.info("Message sent to FCM server");
}
currently I using blogger api in my android app to integrate blogger content with it by using the retrofit and REST APIs, as a json objects.
This a BloggerAPI class I used to retrieve blogs
public class BloggerAPI {
public static final String BASE_URL =
"https://www.googleapis.com/blogger/v3/blogs/2399953/posts/";
public static final String KEY = "THE-KEY";
public static PostService postService = null;
public static PostService getService() {
if (postService == null) {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
postService = retrofit.create(PostService.class);
}
return postService;
}
public interface PostService {
#GET
Call<PostList> getPostList(#Url String url);
}
}
It is used thus
private void getData(){
String url = BloggerAPI.BASE_URL + "?key=" + BloggerAPI.KEY;
if(token != ""){
url = url+ "&pageToken="+token;
}
if(token == null){
return;
}
final Call<PostList> postList = BloggerAPI.getService().getPostList(url);
postList.enqueue(new Callback<PostList>() {
#Override
public void onResponse(Call<PostList> call, Response<PostList> response) {
PostList list = response.body();
token = list.getNextPageToken();
items.addAll(list.getItems());
adapter.notifyDataSetChanged();
Toast.makeText(MainActivity.this, "Sucess", Toast.LENGTH_LONG).show();
}
#Override
public void onFailure(Call<PostList> call, Throwable t) {
Toast.makeText(MainActivity.this,"Error occured",Toast.LENGTH_LONG).show();
Log.i(TAG, "onFailure: "+t.toString());
}
});
}
Till now I succeeded on setup firebase and it's dependencies on the project to be able to send notification manually via firebase console, What I'm trying to do is try to automatically send notifications whenever I post a new post to the blog

You need to use https://fcm.googleapis.com/fcm/send to send notification. Here is the official documentation.
Here is the postman collection to import and test
https://www.getpostman.com/collections/1d2e1f755d25f361c52f

I haven't used blogger API before but as you said that you are creating post via Blogger API's, I can give you a clue to solve your problem.
For example, you have created one API in PHP to send notification (all users, at a time 1000 that you have to manage), You can test using this link
I saw how Adding Post is working. It is giving you success response when you add new post.
You can call PHP API of Notification when you get success response after adding post.
Hope you will convert my words to code. It will help you forsure.
Do let me know, If you have any question.

You can use send FCM notification to the subscribers of blog . reference:-
FCM topic messaging

Sending push notification to specific user using FCM on button click from the app. [duplicate]

After searching the docs I could not find any info on how to send device to device messages using FCM without the use of an external server.
For example, if I was creating a chat application I would need to send push notifications to users about unread messages since they won't be online all the time and I can't have a persistent service in the background that would always be connected to the real time database because that would be too resource heavy.
So how would I send a push notification to a user "A" when a certain user "B" sends him/her a chat message? Do I need an external server for this or can it be done with just Firebase servers?

UPDATE: It is now possible to use firebase cloud functions as the server for handling push notifications. Check out their documentation here
============
According to the docs you must implement a server for handling push notifications in device to device communication.
Before you can write client apps that use Firebase Cloud Messaging, you must have an app server that meets the following criteria:
...
You'll need to decide which FCM connection server protocol(s) you want to use to enable your app server to interact with FCM connection servers. Note that if you want to use upstream messaging from your client applications, you must use XMPP. For a more detailed discussion of this, see Choosing an FCM Connection Server Protocol.
If you only need to send basic notifications to your users from the server. You can use their serverless solution, Firebase Notifications.
See a comparison here between FCM and Firebase Notifications:
https://firebase.google.com/support/faq/#messaging-difference

Making a HTTP POST request with the link https://fcm.googleapis.com/fcm/send with required header and data helped me. In the below code snippet
Constants.LEGACY_SERVER_KEY is a local class variable, you can find this at your Firebase Project Settings->Cloud Messaging->Legacy Server key. You need to pass device registration token i.e. regToken in below code snippet referenced HERE.
At last you need okhttp library dependency in order to get this snippet work.
public static final MediaType JSON
= MediaType.parse("application/json; charset=utf-8");
private void sendNotification(final String regToken) {
new AsyncTask<Void,Void,Void>(){
#Override
protected Void doInBackground(Void... params) {
try {
OkHttpClient client = new OkHttpClient();
JSONObject json=new JSONObject();
JSONObject dataJson=new JSONObject();
dataJson.put("body","Hi this is sent from device to device");
dataJson.put("title","dummy title");
json.put("notification",dataJson);
json.put("to",regToken);
RequestBody body = RequestBody.create(JSON, json.toString());
Request request = new Request.Builder()
.header("Authorization","key="+Constants.LEGACY_SERVER_KEY)
.url("https://fcm.googleapis.com/fcm/send")
.post(body)
.build();
Response response = client.newCall(request).execute();
String finalResponse = response.body().string();
}catch (Exception e){
//Log.d(TAG,e+"");
}
return null;
}
}.execute();
}
further if you want to send message to a particular topic, replace regToken in json like this
json.put("to","/topics/foo-bar")
and don't forget to add INTERNET permission in your AndroidManifest.xml.
IMPORTANT : - Using above code means your server key resides in the client application. That is dangerous as someone can dig into your application and get the server key to send malicious notifications to your users.

You can do it using Volly Jsonobject request....
follow this Steps first:
1 copy legacy server key and store it as Legacy_SERVER_KEY
Legacy Server key
you can see in picture how to get
2 You need Volley dependency
compile 'com.mcxiaoke.volley:library:1.0.19'
Code for send Push:-
private void sendFCMPush() {
String Legacy_SERVER_KEY = YOUR_Legacy_SERVER_KEY;
String msg = "this is test message,.,,.,.";
String title = "my title";
String token = FCM_RECEIVER_TOKEN;
JSONObject obj = null;
JSONObject objData = null;
JSONObject dataobjData = null;
try {
obj = new JSONObject();
objData = new JSONObject();
objData.put("body", msg);
objData.put("title", title);
objData.put("sound", "default");
objData.put("icon", "icon_name"); // icon_name image must be there in drawable
objData.put("tag", token);
objData.put("priority", "high");
dataobjData = new JSONObject();
dataobjData.put("text", msg);
dataobjData.put("title", title);
obj.put("to", token);
//obj.put("priority", "high");
obj.put("notification", objData);
obj.put("data", dataobjData);
Log.e("!_#rj#_##_PASS:>", obj.toString());
} catch (JSONException e) {
e.printStackTrace();
}
JsonObjectRequest jsObjRequest = new JsonObjectRequest(Request.Method.POST, Constants.FCM_PUSH_URL, obj,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.e("!_##_SUCESS", response + "");
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("!_##_Errors--", error + "");
}
}) {
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Authorization", "key=" + Legacy_SERVER_KEY);
params.put("Content-Type", "application/json");
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
int socketTimeout = 1000 * 60;// 60 seconds
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
jsObjRequest.setRetryPolicy(policy);
requestQueue.add(jsObjRequest);
}
Just Call sendFCMPush();

1) subscribe an identical topic name, for example:
ClientA.subcribe("to/topic_users_channel")
ClientB.subcribe("to/topic_users_channel")
2) send messages inside the application
GoogleFirebase : How-to send topic messages

Yes, it's possible to do it without any server. You can create a device group client side and then you exchange messages in the group. However there are limitations:
You have to use the same Google account on the devices
You can't send high priority messages
Reference: Firebase doc See the section "Managing device groups on Android client apps"

Google Cloud Functions make it now possible send push notifications from device-to-device without an app server.
I have made cloud function which is trigger when new message is added in database
It is node.js code
'use strict';
const functions = require('firebase-functions');
const admin = require('firebase-admin'); admin.initializeApp();
exports.sendNotification = functions.database.ref('/conversations/{chatLocation}/{messageLocation}')
.onCreate((snapshot, context) => {
// Grab the current value of what was written to the Realtime Database.
const original = snapshot.val();
const toIDUser = original.toID;
const isGroupChat = original.isGroupChat;
if (isGroupChat) {
const tokenss = admin.database().ref(`/users/${toIDUser}/tokens`).once('value').then(function(snapshot) {
// Handle Promise
const tokenOfGroup = snapshot.val()
// get tokens from the database at particular location get values
const valuess = Object.keys(tokenOfGroup).map(k => tokenOfGroup[k]);
//console.log(' ____________ddd((999999ddd_________________ ' + valuess );
const payload = {
notification: {
title: original.senderName + " :- ",
body: original.content
}
};
return admin.messaging().sendToDevice(valuess, payload);
}, function(error) {
console.error(error);
});
return ;
} else {
// get token from the database at particular location
const tokenss = admin.database().ref(`/users/${toIDUser}/credentials`).once('value').then(function(snapshot) {
// Handle Promise
// The Promise was "fulfilled" (it succeeded).
const credentials = snapshot.val()
// console.log('snapshot ......snapshot.val().name****^^^^^^^^^^^^kensPromise****** :- ', credentials.name);
//console.log('snapshot.....****snapshot.val().token****^^^^^^^^^^^^kensPromise****** :- ', credentials.token);
const deviceToken = credentials.token;
const payload = {
notification: {
title: original.senderName + " :- ",
body: original.content
}
};
return admin.messaging().sendToDevice(deviceToken, payload);
}, function(error) {
console.error(error);
});
}
return ;
});

Google Cloud Functions make it now possible send push notifications from device-to-device without an app server.
From the relevant page on Google Cloud Functions:
Developers can use Cloud Functions to keep users engaged and up to
date with relevant information about an app. Consider, for example, an
app that allows users to follow one another's activities in the app.
In such an app, a function triggered by Realtime Database writes to
store new followers could create Firebase Cloud Messaging (FCM)
notifications to let the appropriate users know that they have gained
new followers.
Example:
The function triggers on writes to the Realtime Database path where followers are stored.
The function composes a message to send via FCM.
FCM sends the notification message to the user's device.
Here is a demo project for sending device-to-device push notifications with Firebase and Google Cloud Functions.

You can use firebase realtime database to do so. You can create data structure for storing chats and add observers for the conversation threads for both users. It still does device - server - device architecture, but in this case there is no additional server on the developers' part. This uses the firebase servers. You can check out a tutorial here (ignore the UI part, although, that is also a good starting point for chat UI frameworks).
Firebase Realtime Chat

If you have fcm(gcm) token of the device to whom you want to send notification. It's just a post request to send the notification.
https://github.com/prashanthd/google-services/blob/master/android/gcm/gcmsender/src/main/java/gcm/play/android/samples/com/gcmsender/GcmSender.java

In my case I use retrofit with this class Message:
public class Message {
private String to;
private String collapseKey;
private Notification notification;
private Data data;
public Message(String to, String collapseKey, Notification notification, Data data) {
this.to = to;
this.collapseKey = collapseKey;
this.notification = notification;
this.data = data;
}
}
Data
public class Data {
private String body;
private String title;
private String key1;
private String key2;
public Data(String body, String title, String key1, String key2) {
this.body = body;
this.title = title;
this.key1 = key1;
this.key2 = key2;
}
}
Notification
public class Notification {
private String body;
private String title;
public Notification(String body, String title) {
this.body = body;
this.title = title;
}
}
this the call
private void sentToNotification() {
String to = "YOUR_TOKEN";
String collapseKey = "";
Notification notification = new Notification("Hello bro", "title23");
Data data = new Data("Hello2", "title2", "key1", "key2");
Message notificationTask = new Message(to, collapseKey, notification, data);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://fcm.googleapis.com/")//url of FCM message server
.addConverterFactory(GsonConverterFactory.create())//use for convert JSON file into object
.build();
ServiceAPI api = new retrofit.create(ServiceAPI.class);
Call<Message> call = api .sendMessage("key=YOUR_KEY", notificationTask);
call.enqueue(new Callback<Message>() {
#Override
public void onResponse(Call<Message> call, retrofit2.Response<Message> response) {
Log.d("TAG", response.body().toString());
}
#Override
public void onFailure(Call<Message> call, Throwable t) {
Log.e("TAG", t.getMessage());
}
});
}
our ServiceAPi
public interface ServiceAPI {
#POST("/fcm/send")
Call<Message> sendMessage(#Header("Authorization") String token, #Body Message message);
}

You can use Retrofit. Subscribe devices to topic news. Send notification from one device to other.
public void onClick(View view) {
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
httpClient.addInterceptor(new Interceptor() {
#Override
public okhttp3.Response intercept(Chain chain) throws IOException {
Request original = chain.request();
// Request customization: add request headers
Request.Builder requestBuilder = original.newBuilder()
.header("Authorization", "key=legacy server key from FB console"); // <-- this is the important line
Request request = requestBuilder.build();
return chain.proceed(request);
}
});
httpClient.addInterceptor(logging);
OkHttpClient client = httpClient.build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://fcm.googleapis.com")//url of FCM message server
.client(client)
.addConverterFactory(GsonConverterFactory.create())//use for convert JSON file into object
.build();
// prepare call in Retrofit 2.0
FirebaseAPI firebaseAPI = retrofit.create(FirebaseAPI.class);
//for messaging server
NotifyData notifydata = new NotifyData("Notification title","Notification body");
Call<Message> call2 = firebaseAPI.sendMessage(new Message("topic or deviceID", notifydata));
call2.enqueue(new Callback<Message>() {
#Override
public void onResponse(Call<Message> call, Response<Message> response) {
Log.d("Response ", "onResponse");
t1.setText("Notification sent");
}
#Override
public void onFailure(Call<Message> call, Throwable t) {
Log.d("Response ", "onFailure");
t1.setText("Notification failure");
}
});
}
POJOs
public class Message {
String to;
NotifyData notification;
public Message(String to, NotifyData notification) {
this.to = to;
this.notification = notification;
}
}
and
public class NotifyData {
String title;
String body;
public NotifyData(String title, String body ) {
this.title = title;
this.body = body;
}
}
and FirebaseAPI
public interface FirebaseAPI {
#POST("/fcm/send")
Call<Message> sendMessage(#Body Message message);
}

Here is walk around how to get notifications without second server apart from the Firebase one. So we use Firebase only, without additional server.
At the mobile app code, we create its own notifications function by Android libraries like here, not using Firebase libraries like here, without Firebase Cloud messaging.
Here is an example with Kotlin:
private fun notification() {
createNotificationChannel()
val intent = Intent(this, LoginActivity::class.java).apply {
flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
}
val pendingIntent: PendingIntent = PendingIntent.getActivity(this, 0, intent, 0)
val notificationBuilder = NotificationCompat.Builder(this, "yuh_channel_id")
.setSmallIcon(R.drawable.ic_send)
.setContentText("yuh")
.setContentText("yuh")
.setAutoCancel(true)
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pendingIntent)
val notificationManager =
getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
notificationManager.notify(0, notificationBuilder.build())
with(NotificationManagerCompat.from(this)) {
// notificationId is a unique int for each notification that you must define
notify(0, notificationBuilder.build())
}
}
private fun createNotificationChannel() {
// Create the NotificationChannel, but only on API 26+ because
// the NotificationChannel class is new and not in the support library
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val name = "yuh_channel"
val descriptionText = "yuh_description"
val importance = NotificationManager.IMPORTANCE_DEFAULT
val CHANNEL_ID = "yuh_channel_id"
val channel = NotificationChannel(CHANNEL_ID, name, importance).apply {
description = descriptionText
}
// Register the channel with the system
val notificationManager: NotificationManager =
getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
notificationManager.createNotificationChannel(channel)
}
In the Firebase database, create collection "pending notifications". Documents should contain user name (to send notification to) and source name (where should user go upon tapping the notification).
In the app code, implement option for adding new records to the Pending Notifications collection. E. g. if user A sends message to user B, then the document with the id of user B (who will be notified) is created in the collection.
In the app code, set up background (when the app is not visible to the user) service. Like here. In the background service, set up a listener for changes in the "Notifications Pending" collection. When the new record with the user id comes to the collection, call the notification function created in the paragrath 1 supra and delete the consequent record from the collection.

So I had an idea here. See: If the FCM, as well as the GCM, has a endpoit to http request where we can send a post json with our message data, including the token (s) of devices that we want this message to be delivered.
So why not send a post to Firebase server with this notification to be delivered to user B? you understand ?
So, you send the message and chat with a call post to ensure delivery of the notification if the user is with your app in the background. I am also in need of it soon, I will test later. What do you say about?

Simplest way :
void sendFCMPush(String msg,String token) {
HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
logging.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
httpClient.addInterceptor(new Interceptor() {
#Override
public okhttp3.Response intercept(Chain chain) throws IOException {
Request original = chain.request();
// Request customization: add request headers
Request.Builder requestBuilder = original.newBuilder()
.header("Authorization", "key="+Const.FIREBASE_LEGACY_SERVER_KEY); // <-- this is the important line
Request request = requestBuilder.build();
return chain.proceed(request);
}
});
httpClient.addInterceptor(logging);
OkHttpClient client = httpClient.build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://fcm.googleapis.com/")//url of FCM message server
.client(client)
.addConverterFactory(GsonConverterFactory.create())//use for convert JSON file into object
.build();
// prepare call in Retrofit 2.0
FirebaseAPI firebaseAPI = retrofit.create(FirebaseAPI.class);
//for messaging server
NotifyData notifydata = new NotifyData("Chatting", msg);
Call<Message> call2 = firebaseAPI.sendMessage(new Message(token, notifydata));
call2.enqueue(new Callback<Message>() {
#Override
public void onResponse(Call<Message> call, retrofit2.Response<Message> response) {
Log.e("## SUCCES #E$#", response.body().toString());
}
#Override
public void onFailure(Call<Message> call, Throwable t) {
Log.e("E$ FAILURE E$#", t.getMessage());
}
});
}
Create Class to make Object:
public class Message {
String to;
NotifyData data;
public Message(String to, NotifyData data) {
this.to = to;
this.data = data;
}
}
Create Class to make Object:
public class Notification {
String title;
String message;
enter code here`enter code here`
public Notification(String title, String message) {
this.title = title;
this.message = message;
}
}

How to send firebase push notification to specific group of user for android

I Have created push notification service using Firebase and I can send notification to either all or single user having FCM id, but I have no idea how to send to specific user.
Also server panel is not created for handling push notification handling If any suggestion for that is there will help more.

Firebase Cloud Messaging (FCM) topic messaging allows you to send a message to multiple devices that have opted in to a particular topic. Based on the publish/subscribe model, topic messaging supports unlimited subscriptions for each app i.e your group is attached to specific topic like news group,sports group etc.
FirebaseMessaging.getInstance().subscribeToTopic("news");
To unsubscribe unsubscribeFromTopic("news")
From Server side you need to set up for specif topic i.e a group of user like this:
https://fcm.googleapis.com/fcm/send
Content-Type:application/json
Authorization:key=AIzaSyZ-1u...0GBYzPu7Udno5aA
{
"to": "/topics/news",
"data": {
"message": "This is a Firebase Cloud Messaging Topic Message!",
}
}
"/topics/news" This will send notification to group of people who have subsribe the news topic

In your android code:
public static void sendNotificationToUser(String user, final String message) {
Firebase ref = new Firebase(FIREBASE_URL);
final Firebase notifications = ref.child("notificationRequests");
Map notification = new HashMap<>();
notification.put("us
ername", user);
notification.put("message", message);
notifications.push().setValue(notification);
}
Create a node and put this code inside:
var firebase = require('firebase');
var request = require('request');
var API_KEY = "..."; // Your Firebase Cloud Server API key
firebase.initializeApp({
serviceAccount: ".json",
databaseURL: "https://.firebaseio.com/"
});
ref = firebase.database().ref();
function listenForNotificationRequests() {
var requests = ref.child('notificationRequests');
ref.on('child_added', function(requestSnapshot) {
var request = requestSnapshot.val();
sendNotificationToUser(
request.username,
request.message,
function() {
request.ref().remove();
}
);
}, function(error) {
console.error(error);
});
};
function sendNotificationToUser(username, message, onSuccess) {
request({
url: 'https://fcm.googleapis.com/fcm/send',
method: 'POST',
headers: {
'Content-Type' :' application/json',
'Authorization': 'key='+API_KEY
},
body: JSON.stringify({
notification: {
title: message
},
to : '/topics/user_'+username
})
}, function(error, response, body) {
if (error) { console.error(error); }
else if (response.statusCode >= 400) {
console.error('HTTP Error: '+response.statusCode+' - '+response.statusMessage);
}
else {
onSuccess();
}
});
}
// start listening
listenForNotificationRequests();
More information with the following link, it is the same thing with a many devices:
Sending notification between android devices with Firebase Database and Cloud Messaging

I don't have enough reputation to edit Burhanuddin Rashid's answer but I think what the OP needs is:
You can replace "to: /topics/news" with registration_ids
{
"registration_ids" : [
"UserInstanceToken1",
"UserInstanceToken2"
]
"data": {
"message": "This is a Firebase Cloud Messaging Topic Message!",
}
}
The User Instance Token can be gotten by
FirebaseInstanceId.getInstance().getToken() in Android.

Enjoy !
public class NotificationSenderThread implements Runnable {
private String title;
private String message;
private String senderToken;
private String recieverToken;
public NotificationSenderThread(String title, String message, String senderToken, String recieverToken) {
this.title = title;
this.message = message;
this.senderToken = senderToken;
this.recieverToken = recieverToken;
}
#Override
public void run() {
try{
JSONObject jsonObject = new JSONObject();
jsonObject.put("title", title);
jsonObject.put("message", message);
jsonObject.put("fcm_token", senderToken);
JSONObject mainObject = new JSONObject();
mainObject.put("to", recieverToken);
mainObject.put("data", jsonObject);
URL url = new URL("https://fcm.googleapis.com/fcm/send");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("Authorization", "key=<SERVER KEY>");
connection.setDoOutput(true);
Log.e("sent",mainObject.toString());
DataOutputStream dStream = new DataOutputStream(connection.getOutputStream());
dStream.writeBytes(mainObject.toString());
dStream.flush();
dStream.close();
String line;
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
StringBuilder responseOutput = new StringBuilder();
while((line = bufferedReader.readLine()) != null ){
responseOutput.append(line);
}
bufferedReader.close();
Log.e("output", responseOutput.toString());
}
catch (Exception e){
Log.e("output", e.toString());
e.printStackTrace();
}
}
}

How to send Device to device notification by using FCM without using XMPP or any other script.?

Is there any way to send Upstream notification message through FCM from one android device to another devices connected with Firebase database.
I know that XMPP server can then receive the upstream messages and send the notifications to the other devices.To receive messages sent with the upstream API i need to implement an XMPP server but there is any other way???

Is there any way to send Upstream notification message through FCM
from one android device to another devices connected with Firebase
database?
Currently it's NOT possible to send messages directly from one device to another.
(or at least it's not possible without introducing a HUGE security vulnerability: more details below)
Full details:
Sending messages to a user device is a pretty serious action!
based on the payload a message can result in spam, phishing, execution of internal methods.
You want this operation to be allowed only be trusted entities, this is why the FCM send API requires the SERVER-API-KEY in the authentication header.
Adding the SERVER-API-KEY in your app code (or communicating it to the app in some other way) IS NOT SAFE. This because apk can be extracted, decompiled, inspected, executed on emulators, executed under debugging and so on.
The best way to implement this today: is to have some sort of server between the two devices:
[DeviceA] -- please send message to B --> [SERVER] -- fcmSendAPI --> [DeviceB]
The server can be as simple as a PHP page, or a more complex XMPP implementation.
An example in Node.js can be found here:
Sending notifications between devices with Firebase Database and Cloud Messaging

Finally, after 2 months of trying to maintain reliable server script myself, I suddenly found OneSignal. It's completely free, supports device-to-device push messages on iOS, Android, WP and browsers.
Hope, I won't get flag for promotion spam, but it's currently the only (and easiest) way to be completely "backendless".
Also, it's completely secure way. Nobody can send push unless he knows special OS user id, which you can store in Firebase Database protected by rules.
UPD: It's not a replacement for Firebase. It has only push service and nothing else
UPD2: Firebase now has Functions, and examples of it usage has sending FCM. You now don't need any other server or service. Read more in official samples https://github.com/firebase/functions-samples

After lots of try finally i got one solution and its work perfectly
Step 1 :Include two library.
compile 'com.squareup.okhttp3:okhttp:3.4.1'
compile 'com.google.firebase:firebase-messaging:9.2.0'
Step 2 : In your MainActivity or from where you want to send notifications.
OkHttpClient mClient = new OkHttpClient();
String refreshedToken = "";//add your user refresh tokens who are logged in with firebase.
JSONArray jsonArray = new JSONArray();
jsonArray.put(refreshedToken);
Step 3: Create one async task which sends notifications to all devices.
public void sendMessage(final JSONArray recipients, final String title, final String body, final String icon, final String message) {
new AsyncTask<String, String, String>() {
#Override
protected String doInBackground(String... params) {
try {
JSONObject root = new JSONObject();
JSONObject notification = new JSONObject();
notification.put("body", body);
notification.put("title", title);
notification.put("icon", icon);
JSONObject data = new JSONObject();
data.put("message", message);
root.put("notification", notification);
root.put("data", data);
root.put("registration_ids", recipients);
String result = postToFCM(root.toString());
Log.d("Main Activity", "Result: " + result);
return result;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
try {
JSONObject resultJson = new JSONObject(result);
int success, failure;
success = resultJson.getInt("success");
failure = resultJson.getInt("failure");
Toast.makeText(MainActivity.this, "Message Success: " + success + "Message Failed: " + failure, Toast.LENGTH_LONG).show();
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "Message Failed, Unknown error occurred.", Toast.LENGTH_LONG).show();
}
}
}.execute();
}
String postToFCM(String bodyString) throws IOException {
public static final String FCM_MESSAGE_URL = "https://fcm.googleapis.com/fcm/send";
final MediaType JSON
= MediaType.parse("application/json; charset=utf-8");
RequestBody body = RequestBody.create(JSON, bodyString);
Request request = new Request.Builder()
.url(Url.FCM_MESSAGE_URL)
.post(body)
.addHeader("Authorization", "key=" + "your server key")
.build();
Response response = mClient.newCall(request).execute();
return response.body().string();
}
Step 4 : Call in onclick of your button
btnSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
sendMessage(jsonArray,"Hello","How r u","Http:\\google.com","My Name is Vishal");
}
});

Cannot access HTTP headers from Cloud Endpoints Python

I'm implementing custom authentication in Google Cloud Endpoints for an Android app. To do so, I'm sending an auth token in an HTTP header. From Android:
private static final String HEADER_AUTH_TOKEN = "HTTP_AUTHORIZATION";
private GoogleClientRequestInitializer requestInitializer =
new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> request) throws IOException {
HttpHeaders headers = request.getRequestHeaders();
if (authPrefs.authToken().exists()) {
headers.set(HEADER_AUTH_TOKEN, authPrefs.authToken().get().toString());
}
request.setRequestHeaders(headers);
}
};
Api.Builder apiBuilder = new Api.Builder(
AndroidHttp.newCompatibleTransport(),
new GsonFactory(),
null);
return apiBuilder.setApplicationName(APPLICATION_NAME)
.setGoogleClientRequestInitializer(requestInitializer)
.build()
Then in Python I'm trying to retrieve the auth token header:
import os
auth_token = os.getenv('HTTP_AUTHORIZATION')
auth_token is None. What am I missing?

It turns out "HTTP_" was being prepended to any HTTP header sent. HTTP_AUTHORIZATION was being sent as "HTTP_HTTP_AUTHORIZATION".