AndroidAndroid V4 Mobile Push Gateway Tutorial for Realtime Apps

 
Requires that the Push Notifications add-on is enabled for your key. How do I enable add-on features for my keys? - see http://www.pubnub.com/knowledge-base/discussion/644/how-do-i-enable-add-on-features-for-my-keys

PubNub's Mobile Push Gateway feature enables developers to bridge native PubNub publishing with 3rd-party push notification services including Google Android GCM (Google Cloud Messaging)/FCM (Firebase Cloud Messaging), Apple iOS APNS (Apple Push Notification Service), and Microsoft Windows Phone MPNS (Microsoft Push Notification Service).

By using the Mobile Push Gateway, developers can eliminate the need for developing, configuring, and maintaining additional server-side components for 3rd-party push notification providers.

For mission critical messaging, PubNub recommends implementing PubNub native messaging functionality. PubNub native messaging touts a low-latency, bi-directional notification solution that can be delivered to any mobile device, secure, access restricted, and encrypted message payloads of up to 32KB, and the ability to recover missed messages with Storage & Playback (history) APIs.

Despite the advantages of the native PubNub approach, there are cases where a developer may choose to utilize a 3rd-party notification system, for example, when migrating existing applications already utilizing 3rd-party notification systems to PubNub native messaging. On iOS, Android, and Windows applications where running in the background is not an option, the Mobile Push Gateway provides a method to send messages quickly and reliably via PubNub whether or not the application is in the foreground or background.

Native PubNub Publish and Subscribe operation dictates that when a message is published by a client on a specific channel, all clients subscribing to that channel will receive that message.

When the Mobile Push Gateway is enabled, you may associate unique mobile devices (via their device push tokens) with PubNub channel names.  Once this association is made, when a message is published to a channel that has been associated with an GCM/FCM, APNS, or MPNS device, all associated GCM/FCM, APNS, or MPNS devices will receive that message via their associated (GCM/FCM, APNS, or MPNS) native service.

Behind the scenes, the PubNub Mobile Push Gateway establishes an authenticated connection to GCM/FCM, APNS, or MPNS service providers based on your registered configuration.

Device Connected
[currently subscribed]
Device Token/ID
Registered to Channel
Device Token/ID
Not Registered to Channel
App in ForegroundApp in BackgroundApp in ForegroundApp in Background
  • Receive Publish Directly
  • Push Notification Sent
  • Receive Push Notification
    Content [no UI notification]
[Android Only]
  • Receive Publish Directly
  • Push Notification Sent
  • Push Notification Received
    [with UI Notification]

[iOS]
  • Publish Not Received*
  • Push Notification Sent
  • Push Notification Received
    [with UI Notification]
  • Receive Publish Directly
  • No Push Notification sent for this device
[Android Only]
  • Receive Publish Directly if subscribed in background
  • No Push Notification sent for this device

[iOS]
  • Publish Not Received
  • No Push Notification sent for this device
Device Disconnected
[not currently subscribed]
Device Token/ID
Registered to Channel
Device Token/ID
Not Registered to Channel
App in ForegroundApp in BackgroundApp in ForegroundApp in Background
  • Publish Not Received
  • Push Notification Sent
  • Receive Push Notification
    Content [no UI notification]
  • Publish Not Received
  • Push Notification Sent
  • Push Notification Received
    [with UI Notification]
  • Publish Not Received
  • No Push Notification sent for this device
  • Publish Not Received
  • No Push Notification sent for this device

* If the app has background permissions the realtime messages will be received and push notifications may not be necessary unless the app is not running at all. For this, developers should actually mute the push notification within didReceiveRemoteNotification delegate instead of muting the realtime message from PubNub.

 

FCM is just a rebranding of GCM and there is no function difference to handle it in PubNub. The PubNub server's still expect a pn_gcm as part of the payload.

Please check this link to migrate an existing GCM client app on Android to Firebase Cloud Messaging (FCM).

Before you can use PubNub Mobile Push Gateway with GCM/FCM, you must first setup your GCM/FCM configuration.
  1. Create a Firebase Project - https://console.firebase.google.com
  2. Click Add Firebase to your Android app and follow the steps there
  3. Go to Project settings (Click the gear icon at the top left, next to Project overview)
  4. Click the Cloud messaging tab and find the Server key there
  5. Once you've obtained the API Key, login to the PubNub Admin Console, and scroll down to Push Notifications → Google Cloud Messaging and click on Add to add your API Key.
https://firebase.google.com/docs/cloud-messaging/server provides general information about the Google-side of this process.
To register for receipt of messages arriving on a PubNub channel to be forwarded to an Android device via GCM/FCM, you must first retrieve that Android device's unique ID, otherwise know as its registration token.
The following instructions taken directly from here, demonstrate how to retrieve an Android registration token:
  1. An Android application needs to register with GCM/FCM connection servers before it can receive messages.
  2. When an app registers, it receives a registration token and sends it to the app server. The client app should store a boolean value indicating whether the registration token has been sent to the server.
  3. Google provides the Firebase Instance ID API to handle the creation and updating of registration tokens. To obtain a token, call FirebaseInstanceId.getInstance().getInstanceId().
    FirebaseInstanceId.getInstance().getInstanceId()
        .addOnSuccessListener(new OnSuccessListener<InstanceIdResult>() {
            @Override
            public void onSuccess(InstanceIdResult instanceIdResult) {
                String token = instanceIdResult.getToken();
            }
    });
  4. Once you've received your registration token, make sure to send it to your server (or PubNub's). The listener service's onNewToken() method should be invoked if the FCM registration token has been refreshed. The token can be updated, if the security of the previous token had been compromised. New tokens are received inside same method onNewToken() method, within your extension of the FirebaseMessagingService class. More info here.
    @Override
    public​ void​ onNewToken​(String token) {
        Log.d(TAG, "Refreshed token: " + token);
        // a good place to fire a PubNub#addPushNotificationsOnChannels request,
        // to resubscribe the client since it's no longer subscribed
        // because it has a new token
        // and the previous one used for subscribtion is invalid
    }
Once you have successfully retrieved your registration token and associated it with PubNub channels, before you can receive any GCM/FCM messages, you must implement the FirebaseMessagingService.onMessageReceived() method.
The following instructions are taken directly from https://firebase.google.com/docs/cloud-messaging/android/client demonstrate how to implement the FirebaseMessagingService.onMessageReceived() method:
  • To receive simple downstream messages, use a service that extends FirebaseMessagingService to handle messages
  • By overriding the method onMessageReceived(), you can perform actions based on the received message
    @Override
    public​ void​ onMessageReceived​(RemoteMessage remoteMessage) {
        Log.d(TAG, "push notification received!");
        // remoteMessage.getData() is the extra data you sent via PubNub#publish()
        sendNotification(message);
    }
    
addPushNotificationsOnChannels and its variant methods associate a channel to a registration token.
pubnub.addPushNotificationsOnChannels()
	.pushType(PNPushType.GCM)
	.channels(Arrays.asList("ch1", "ch2", "ch3"))
	.deviceId("googleDevice")
	.async(new PNCallback<PNPushAddChannelResult>() {
		@Override
		public void onResponse(PNPushAddChannelResult result, PNStatus status) {
			// handle response.
		}
	});
removePushNotificationsFromChannels and its variant methods associate a channel to a registration token.
pubnub.removePushNotificationsFromChannels()
	.deviceId("googleDevice")
	.channels(Arrays.asList("ch1", "ch2", "ch3"))
	.pushType(PNPushType.GCM)
	.async(new PNCallback<PNPushRemoveChannelResult>() {
		@Override
		public void onResponse(PNPushRemoveChannelResult result, PNStatus status) {
		
		}
	});
auditPushChannelProvisions lists channels registered to device token.
pubnub.auditPushChannelProvisions()
	.deviceId("googleDevice")
	.pushType(PNPushType.GCM)
	.async(new PNCallback<PNPushListProvisionsResult>() {
		@Override
		public void onResponse(PNPushListProvisionsResult result, PNStatus status) {
		
		}
	});
The equivalent method calls are also available via our Android, Objective-C, Swift, and .NET Mobile Gateway guides.
PubNub SDKs natively support associating device/registration tokens to channel names. To achieve this, they use a REST wrapper to add, remove, and list device registration IDs by channel.
The following serves as a REST request reference for adding, removing, and listing associated devices and channels. Whenever possible, use the native method call available in the SDK, instead of manually issuing the REST call.
http://pubsub.pubnub.com/v1/push/sub-key/<SUB_KEY>/devices/<REG_ID>?<OPERATION>=<CHANNEL_LIST>&type=<TYPE>
ParameterTypeRequiredDescription
OPERATION AND CHANNEL_LIST
OPERATION is one of add, list or remove. CHANNEL_LIST is a comma separated string of channels.
Optional
If not specified, defaults to the the list operation.
SUB_KEY
String
Yes
This is your PN API subscribeKey.
REG_ID
string
Yes
The device registraton ID.
TYPE
TYPE is one of gcm, apns, and mpns.
Optional
If no type specified, server will default to apns (for backwards compatibility)

[1, "Modified Channels"]
  • On success returns a 200 JSON Array of [1, "Modified Channels"].
  • On error returns 403 for PAM errors. Any status code other than 200 or 403 should be handled as fatal and retried at your discretion.
http://pubsub.pubnub.com/v1/push/sub-key/demo/devices/ALICE?type=gcm | apns | mpns &add=myCH
http://pubsub.pubnub.com/v1/push/sub-key/demo/devices/ALICE?type=gcm | apns | mpns&add=news,sports
http://pubsub.pubnub.com/v1/push/sub-key/demo/devices/ALICE?type=gcm | apns | mpns
http://pubsub.pubnub.com/v1/push/sub-key/demo/devices/ALICE?type=gcm | apns | mpns&remove=myCH
http://pubsub.pubnub.com/v1/push/sub-key/demo/devices/ALICE/remove?type=gcm | apns | mpns
The following examples show how to publish to GCM/FCM devices with the PubNub Android V4 client:
Map<String, Object> payload = new HashMap<>();
payload.put("pn_apns", <apple Payload>);
payload.put("pn_mpns", <microsoft payload>);
payload.put("pn_gcm", <google payload>);

pubnub.publish()
	.message(payload)
	.channel("my_channel")
	.async(new PNCallback<PNPublishResult>() {
		@Override
		public void onResponse(PNPublishResult result, PNStatus status) {
			// handle publish result.
		}
	});
To make it properly formatted for receipt via GCM/FCM, we must add a pn_gcm.data attribute to it, like so:
{
    "name": "Fitchwitz Technology",
    "pn_gcm": {
        "data": {
            "title_for_mobile": "Fitchwitz Technology",
            "summary_for_mobile": [ "Fitchwitz antivirals... more info at http://FitchwitzTech.com/fooz" ]
        }
    },
    "snapshot": {
        "last": 40.52,
        "volume": "3495345",
        "change": ["+4.02","+7.45%"]
    },
    "ticker": {
        "newsflash": [
            "Fitchwitz antivirals in the total number of shares being sold in the public offering have exercised in full.",
            "The offering price of all their option to purchase an additional zillion shares of its common stock is sweet.",
            "Offering is expected to occur today announced public offering the offering when 100 shares went byebye."
        ],
        "url": "http://FitchwitzTech.com/fooz"
    }
}
 
pn_gcm.data must contain a dictionary of keys and values. pn_gcm.data cannot be a string, int, or array.

This message will be received in its entirety by all native PubNub client subscribers (including any pn_gcm, pn_apns, and pn_mpns contents), however, any devices registered to receive messages on the published channel via GCM/FCM, APNS, or MPNS will only receive the content contained within pn_gcm, pn_apns, or pn_mpns, respectively.

 
The following message is received, in its entirety, to all native PubNub client subscribers.
{
    "name": "Fitchwitz Technology",
    "snapshot": {
        "last": 40.52,
        "volume": "3495345",
        "change": ["+4.02","+7.45%"]
    },
    "ticker": {
        "newsflash": [
            "Fitchwitz antivirals in the total number of shares being sold in the public offering have exercised in full.",
            "The offering price of all their option to purchase an additional zillion shares of its common stock is sweet.",
            "Offering is expected to occur today announced public offering when 100 shares went byebye."
        ],
        "url": "http://FitchwitzTech.com/fooz"
    }
}
JsonObject apnsPayload = new JsonObject();
JsonObject apsPayload  = new JsonObject();

JsonObject gcmPayload  = new JsonObject();
JsonObject dataPayload = new JsonObject();

JsonObject payload = new JsonObject();

apsPayload.addProperty("alert", "hi");
apsPayload.addProperty("badge", 2);
apsPayload.addProperty("sound", "melody");

apnsPayload.add("aps", apsPayload);
apnsPayload.addProperty("c", "3");

dataPayload.addProperty("a", "1");

gcmPayload.add("data", dataPayload);
gcmPayload.addProperty("b", "2");

payload.add("pn_apns", apnsPayload);
payload.add("pn_gcm", gcmPayload);

pubnub.publish()
    .message(payload)
    .channel("my_channel")
    .async(new PNCallback<PNPublishResult>() {
        @Override
        public void onResponse(PNPublishResult result, PNStatus status) {
            // handle publish result, status always present, result if successful
            // status.isError to see if error happened
        }
    });

Publishing using the above referenced dictionary structure, or via the literal JSON snippet, both have the same effect.

If you are interested in sending unique messages on a per-Mobile Gateway type in a single publish, just include all or some additional endpoint key (pn_apns, pn_gcm and pn_mpns) in your message.

Native PubNub devices will receive the ENTIRE message payload, but 3rd-Party endpoints by type will only receive the data encapsulated in their associated endpoint key.

In the below example:

  • Associated APNS devices will receive only the data within the pn_apns key.
  • Associated GCM/FCM devices will receive only the data within the pn_gcm key.
  • Associated MPNS devices will receive only the data within the pn_mpns key.
  • Native PubNub subscribers will receive the entire object literal, including the pn_apns, pn_gcm, pn_mpns, and full_gamekeys.
    {
        "pn_apns" : {
            "aps" : {
                "alert" : "Game update 49ers touchdown",
                "badge" : 2
            },
            "teams" : ["49ers", "raiders"],
            "score" : [7, 0]
        },
        "pn_gcm": {
            "data" : {
                "summary" : "Game update 49ers touchdown",
                "teams" : ["49ers", "raiders"],
                "score" : [7, 0],
                "lastplay" : "5yd run up the middle"
            }
        },
        "pn_mpns" : {
            "type" : "flip",
            "title" : "Front title",
            "count" : 1,
            "back_title" : "Back Tile",
            "back_content" : "Back message"
        },
        "full_game" : {
            "date" : "2014.05.20",
            "foobar" : "Data that is not pertinent to devices"
        }
    }

For any given published message, you may include any combination of pn_* and non-pn_* keys and data.

Yes, you can set an expiration time when publishing a push notification via APNS. Timeouts are measured in seconds (default is 3600, or 1 hour) and are set via the top level key of pn_ttl. For example, to set the timeout to 60 seconds (1 minute):

    {
        "pn_apns" : {
            "aps" : {
                "alert" : "You got mail."
            }
        },
        "pn_ttl" : 60
    }

Note that Apple will only queue a single message per device/app. For example, if you send 10 push notifications to a device that's powered off, then all notifications besides the last one are discarded, regardless of TTL.

Sometimes it is desirable to exclude a device from a group push notification. For example if a user has multiple devices registered to same channel and wants to send a group push notification he/she may want to not receive the same push on own devices. We support the pn_exceptions parameter in the payload to handle this. The pn_exceptions parameter accepts "device push tokens" (the same token used to register the device for push messages).

    {
        "pn_apns" : {
            "aps" : {
                "alert" : {
                    "body" : "hello"
                }
            },
            "pn_exceptions" : [
                "da284603e1e96ac453541cd1942659808a69c09fb1dbb2e3c11aba6cdcaec642"
            ]
        }
    }
    {
        "pn_apns" : {
            "aps" : {
                "alert" : {
                    "body" : "hello"
                }
            },
            "pn_exceptions" : [
                "5821e49019f3554872c3897dd800367bf803aa28871699b0e5960fba203446e9",
                "da284603e1e96ac453541cd1942659808a69c09fb1dbb2e3c11aba6cdcaec642"
            ]
        }
    }
    {
        "pn_gcm" : {
            "alert" : "hello",
            "pn_exceptions" : [
                "2643d955c7f2506e55f225b56da7eb8676cced80de93df51aad7569ee833b92f"
            ]
        }
    }
Inform customers of unregistered/inactive push devices via a webhook (similar to presence webhooks).
The following events will trigger the webhook. All errors should trigger immediately after a push (except for feedback which can happen after 5 minutes of a push).
  • Feedback -­ Apple feedback service ­- PubNub push server polls the feedback server after 5 minutes of a push to get list of inactive/uninstalled devices.
  • Remove - Invalid token error -­ Usually indicates when a sandbox token is used in production or vice versa.
  • Update -­ Canonical ID -­ The device has multiple tokens (old and new), replace the old token with new token.
  • Remove - NotRegistered - App was uninstalled or no longer configured for push notifications.
	HTTP POST
	Content­Type: application/json
	{
		"sub_key" : <sub­key>,
		"action" : <action contains extra details about how the device was removed ­ see events section>
		"device" : <device token>,
		"platform" : "apns|gcm|mpns",
		"timestamp" : <unix timestamp (utc) when the device was removed>
	}
An APNS device was uninstalled from feedback.
	{
		"sub_key" : "sub­c­e0d8405a­b823­11e2­89ba­02ee2ddab7fe",
		"action" : "feedback",
		"device" :"904181a3fc8bfaf95cc40551d81b5b8d0bd1d42c38b1e496648132a555325e8c",
		"platform" : "apns",
		"timestamp" : 1444241230
	}
A GCM/FCM device was updated from old token APA91bEgK4D to new token ta28zYhV.
	{
		"sub_key" : "sub­c­4745b1e4­19ba­11e4­bbbf­02ee2ddab7fe",
		"action" : "update",
		"old_device": "APA91bEgK4D"
		"device" : "ta28zYhV"
		"platform" : "gcm",
		"timestamp" : 1441230130
	}
A MPNS device was uninstalled.
	{
		"sub_key" : "sub­c­8a888f2c­d7a1­11e3­8c07­02ee2ddab7fe",
		"action" : "remove",
		"device" : "http://sn1.notify.live.net/throttledthirdparty/01.00/AQG2MdvoLlZFT7­VJ2TJ5LnbAgAAAAADAQAAAAQUZm52OkRFNzg2NTMxMzlFMEZFNkMFBlVTU0MwMQ"
		"platform" : "mpns",
		"timestamp" : 1400218910
	}
 
If a device has been registered to receive Mobile Push Gateway messages via GCM/FCM, APNS, or MPNS, and is also running a native PubNub Android, iOS, or Windows client SDK, and is natively subscribed to the same associated channel via the native PubNub client SDK, it will receive the message twice -- once via the Mobile Push Gateway, and once via the native PubNub client SDK. You will need to manually add logic to de-duplicate in this case.

If you are experiencing issues publishing to devices via the PubNub Mobile Gateway, the following are debug techniques that may help narrow down the issue. Each of them circumvents PubNub's Mobile Push Gateway logic to ensure that your device push tokens, applications, and registration/certificates are configured correctly.

If the following scripts are not working for you, then PubNub isn't a variable in the cause of the issue -- successful results with the below scripts script is a pre-requisite for PubNub Mobile Gatway logic to work.  Regardless if its a PubNub issue or not, we're always happy to help!  By getting us the results of the following tests when opening a support ticket, it may save a lot time isolating the root cause of your issue.

Use this script to publish a message to APNS, completely circumventing PubNub infrastructure. It requires an APNS certificate and an iOS device token.

Use the following curl command to publish a message to GCM/FCM, completely circumventing PubNub infrastructure. It requires a registration ID. Taken from Google's GCM/FCM page.

    curl --header "Authorization: key=<API_KEY>" \
        --header Content-Type:"application/json" \
        https://gcm-http.googleapis.com/gcm/send \
        -d "{\"registration_ids\":[\"ABC\"]}"

Use the following curl command to publish a message to MPNS, completely circumventing PubNub infrastructure. It requires a device push token.

    curl -v -H "Content-Type:text/xml" -H "X-WindowsPhone-Target:Toast" -H "X-NotificationClass:2" -X POST -d "<?xml version='1.0' encoding='utf-8'?><wp:Notification xmlns:wp='WPNotification'><wp:Toast><wp:Text1>My title</wp:Text1><wp:Text2>My subtitle</wp:Text2></wp:Toast></wp:Notification>" http://dm2.notify.live.net/throttledthirdparty/01.00/AQGiZ6EjjX0ySLELCr3iykPvAgAAAAADBAAAAAQUZm52OkRFNzg2NTMxMzlFMEZFNkMFBlVTU0MwMQ

You have implemented mobile push notifications into your PubNub application but now you are having some troubles. Maybe it's missing messages on client devices, getting duplicate messages, getting messages meant for another user/device. Whatever it is, we will provide the best tools and techniques for finding the root cause and resolving, or at least just getting all the necessary data points to send to PubNub Support to assist with troubleshooting.

You can do some high level debugging using the channel's -pndebug channel and checking to see if the device is still registered to the channel. Messages from -pndebug come from the APNS and GCM/FCM services (from Apple and Google, not PubNub). Here are the steps:

  1. Use the PubNub Debug Console to subscribe to the channel's -pndebug channel. If the channel you are publishing to is foo, then subscribe to foo-pndebug. Make sure you use the right pub/sub keys.
  2. Add 'pn_debug':true to your message payload at the top level.
        {
            "pn_gcm": {
                "data": {
                    "message": "hello"
                }
            },
            "pn_apns": {
                "aps": {
                    "alert": "hello"
                }
            },
            "pn_debug": true
        }
  3. Publish the message to channel foo, not to the channel's -pndebug channel. You can publish from your client or server application or from another instance of Debug Console (again, make sure you use the same pub/sub keys). You should see useful error messages in the Debug Console where you are subscribing to foo-pndebug, if there are any problems with the push message registration.

The following message shows how many devices successfully received the push notification that were registered for push messages on the target channel for each push service.

Devices found for push notification apns: 2 gcm: 3 mpns: 0

The following messages are examples of the types of messages that GCM/FCM and APNS push services can send back to PubNub's mobile push notification gateway servers.

    gcm Error: InvalidRegistration Devices: null
    gcm WARNING error: NotRegistered, sub_key: sub-c-..., channel: my_channel, reg_id: APA91bHRRxfHHB_T0AVojoJx..., timetoken: 14567269547473296
    apns INFO Certificate for sub-c-... valid (expiration: Sep 14 08:58:26 2016 GMT)
    apns ERROR Error on APNS send for subkey sub-c-... / channel gone_fishing / device 2a0a6234ffdb85df6624cf0546...: invalid token

All of the above messages can be sent to your server using PubNub's Mobile Push Gateway web hooks. A web hook is a URL (that you can have us configure on your keys) to a REST endpoint on your server. As messages come back to PubNub from the mobile push notification services, PubNub will relay them onto your REST endpoint for you to log and process as you require. Contact PubNub Support to request this configuration for your keys.

You can also check to see if the device is still registered to the channel after you publish the push notification using a simple REST URL in the browser.

  1. http://pubsub.pubnub.com/v1/push/sub-key/your_sub_key/devices/device_reg_token?type=push_type
  • where push_type is either gcm or apns
  • and device_reg_token is the device's registration token

This will return all channels the device is still registered for push notification for the push type provided.

Example of response:

["demo","demo1","demo2"]

If that list comes back empty then there was likely a device registration token issue (invalid token or device not registered, for example). This might happen because the device token was reported as invalid by the push notification services (APNS or GCM/FCM) and PubNub in turn unregisters that device token from all channels. But the -pndebug channel should reveal the reason for this to you.

Most times it is not PubNub that is causing the push notification issues. Often it is an invalid registration token (APNS or GCM/FCM) or a device with two valid registration tokens (yes, it can actually happen) or the push service cert or key is no longer valid. Testing push notifications without PubNub getting involved is the best way to eliminate, or hone in on, the area of probable fault.

There are a few good online tools for testing GCM/FCM push notifications and one native Mac app.

For APNS, you can run a simple Python script that uses your push certificate (.pem file) to verify that the certificate is valid. And optionally, you can specify a device registration token to which test push notifications will be sent. See our knowledge base article, How Do I Test My PEM Key, for full details.

For more rich UI/UX tools, you can find APNS test apps for the Mac (in the App Store) as well as online web apps:

See also:

  1. Apple Doc Troubleshooting Push Notifications

For additional platform and endpoint information, please see our detailed Android, Objective-C, Swift, and .NET Mobile Gateway guides.