Java REST wrapper for Windows Azure Notification Hubs

Java Back-end SDK for Windows Azure Notification Hubs. Using REST APIs.

Implements most of the Notification Hubs REST operations to perform Hub CRUDs, registration/installation management and send notification.

Please send feedback/comments, and pull requests... :)

New

• Async operations via Java NIO
• Baidu PNS support
• Import/Export jobs
• Scheduled notifications
• Installation API support
• Namespace Manager is introduced to perform CRUDs against Notification Hub(s)

#Use

##Compile and build Use Maven.

To build:

mvn package

##Code

Notification Hub CRUDs

Create a namespace manager:

NamespaceManager namespaceManager = new NamespaceManager("connection string");

Create hub:

NotificationHubDescription hub = new NotificationHubDescription("hubname");
hub.setWindowsCredential(new WindowsCredential("sid","key"));
hub = namespaceManager.createNotificationHub(hub);

Get hub:

hub = namespaceManager.getNotificationHub("hubname");

Update hub:

hub.setMpnsCredential(new MpnsCredential("mpnscert", "mpnskey"));
hub = namespaceManager.updateNotificationHub(hub);

Delete hub:

namespaceManager.deleteNotificationHub("hubname");

Create/Update/Delete Registrations

Create a hub client

hub = new NotificationHub("connection string", "hubname");

Create Windows registration:

WindowsRegistration reg = new WindowsRegistration(new URI(CHANNELURI));
reg.getTags().add("myTag");
reg.getTags().add("myOtherTag");	
hub.createRegistration(reg);

Create iOS registration:

AppleRegistration reg = new AppleRegistration(DEVICETOKEN);
reg.getTags().add("myTag");
reg.getTags().add("myOtherTag");
hub.createRegistration(reg);

Analogous for Android (GCM), Windows Phone (MPNS), and Kindle Fire (ADM).

Create template registrations:

WindowsTemplateRegistration reg = new WindowsTemplateRegistration(new URI(CHANNELURI), WNSBODYTEMPLATE);
reg.getHeaders().put("X-WNS-Type", "wns/toast");
hub.createRegistration(reg);

Create registrations using create registrationid+upsert pattern (removes duplicates deriving from lost responses if registration ids are stored on the device):

String id = hub.createRegistrationId();
WindowsRegistration reg = new WindowsRegistration(id, new URI(CHANNELURI));
hub.upsertRegistration(reg);

Update registrations:

hub.updateRegistration(reg);

Delete registrations:

hub.deleteRegistration(regid);

Query registrations

Get single registration:

hub.getRegistration(regid);

All collection queries support $top and continuation tokens.

Get all registrations in hub:

hub.getRegistrations();

Get registrations with tag:

hub.getRegistrationsByTag("myTag");

Get registrations by channel:

hub.getRegistrationsByChannel("devicetoken");

Send Notifications

The Notification object is simply a body with headers, some utility methods help in building the native and template notifications objects.

Send Windows native:

Notification n = Notification.createWindowsNotification("WNS body");

// broadcast
hub.sendNotification(n);
	
// send to tags	
Set<String> tags = new HashSet<String>();
tags.add("boo");
tags.add("foo");
hub.sendNotification(n, tags);

// send to tag expression		
hub.sendNotification(n, "foo && ! bar");

Send iOS native:

Notification n = Notification.createAppleNotifiation("APNS body");
hub.sendNotification(n);

Analogous for Android, Windows Phone, Kindle Fire and Baidu PNS.

Send template notification:

Map<String, String> prop =  new HashMap<String, String>();
prop.put("prop1", "v1");
prop.put("prop2", "v2");
Notification n = Notification.createTemplateNotification(prop);
	
hub.sendNotification(n);

Installation API usage

Installation API is alternative mechanism for registration management. Instead of maintaining multiple registrations which is not trivial and may be easily done wrongly or inefficiently, it is now possible to use SINGLE Installation object. Installation contains everything you need: push channel (device token), tags, templates, secondary tiles (for WNS and APNS). You don't need to call Service to get Id anymore - just generate GUID or any other identifier, keep it on device and send to your backend together with push channel (device token). On the backend you should only do single call: CreateOrUpdateInstallation, it is fully idempotent, so feel free to retry if needed.

As example for Amazon Kindle Fire it looks like this:

Installation installation = new Installation("installation-id", NotificationPlatform.Adm, "adm-push-channel");
hub.createOrUpdateInstallation(installation);

Need to add something new - just do it:

installation.addTag("foo");
installation.addTemplate("template1", new InstallationTemplate("{\"data\":{\"key1\":\"$(value1)\"}}","tag-for-template1"));
installation.addTemplate("template2", new InstallationTemplate("{\"data\":{\"key2\":\"$(value2)\"}}","tag-for-template2"));
hub.createOrUpdateInstallation(installation);

For advanced scenarios we have partial update capability which allows to modify only particular properties of the installation object. Basically partial update is subset of JSON Patch operations you can run against Installation object.

PartialUpdateOperation addChannel = new PartialUpdateOperation(UpdateOperationType.Add, "/pushChannel", "adm-push-channel2");
PartialUpdateOperation addTag = new PartialUpdateOperation(UpdateOperationType.Add, "/tags", "bar");
PartialUpdateOperation replaceTemplate = new PartialUpdateOperation(UpdateOperationType.Replace, "/templates/template1", new InstallationTemplate("{\"data\":{\"key3\":\"$(value3)\"}}","tag-for-template1")).toJson());
hub.patchInstallation("installation-id", addChannel, addTag, replaceTemplate);

Delete Installation:

hub.deleteInstallation(installation.getInstallationId());

Keep in mind that CreateOrUpdate, Patch and Delete are eventually consistent with Get. In fact operation just goes to the system queue during the call and will be executed in background. Moreover Get is not designed for main runtime scenario but just for debug and troubleshooting purposes, it is tightly throttled by the service.

Send flow for Installations is the same as for Registrations. We've just introduced an option to target notification to the particular Installation - just use tag "InstallationId:{desired-id}". For case above it would look like this:

Notification n = Notification.createWindowsNotification("WNS body");
hub.sendNotification(n, "InstallationId:{installation-id}");

For one of several templates:

Map<String, String> prop =  new HashMap<String, String>();
prop.put("value3", "some value");
Notification n = Notification.createTemplateNotification(prop);
hub.sendNotification(n, "InstallationId:{installation-id} && tag-for-template1");

Schedule Notifications (available for STANDARD Tier)

The same as regular send but with one additional parameter - scheduledTime which says when notification should be delivered. Service accepts any point of time between now + 5 minutes and now + 7 days.

Schedule Windows native:

Calendar c = Calendar.getInstance();
c.add(Calendar.DATE, 1);	

Notification n = Notification.createWindowsNotification("WNS body");

hub.scheduleNotification(n, c.getTime());

Import/Export (available for STANDARD Tier)

Sometimes it is required to perform bulk operation against registrations. Usually it is for integration with another system or just a massive fix to say update the tags. It is strongly not recomended to use Get/Update flow if we are talking about thousands of registrations. Import/Export capability is designed to cover the scenario. Basically you provide an access to some blob container under your storage account as a source of incoming data and location for output.

Submit export job:

NotificationHubJob job = new NotificationHubJob();
job.setJobType(NotificationHubJobType.ExportRegistrations);
job.setOutputContainerUri("container uri with SAS signature");
job = hub.submitNotificationHubJob(job);

Submit import job:

NotificationHubJob job = new NotificationHubJob();
job.setJobType(NotificationHubJobType.ImportCreateRegistrations);
job.setImportFileUri("input file uri with SAS signature");
job.setOutputContainerUri("container uri with SAS signature");
job = hub.submitNotificationHubJob(job);

Wait until job is done:

while(true){
	Thread.sleep(1000);
	job = hub.getNotificationHubJob(job.getJobId());
	if(job.getJobStatus() == NotificationHubJobStatus.Completed)
		break;
}		

Get all jobs:

List<NotificationHubJob> jobs = hub.getAllNotificationHubJobs();

URI with SAS signature

Basically it is URL of some blob file or blob container plus set of parameters like permissions and expiration time plus signature of all these things made using account's SAS key. Azure Storage Java SDK has rich capabilities including creation of such kind of URIs. As simple alternative you can take a look at ImportExportE2E test class which has very basic and compact implementation of signing algorithm.

References:

MSDN documentation

Windows Azure Notification Hubs Service Page

Nice tutorials that are easy to translate in Java:

• Get Started with Notification Hubs
• Send breaking news
• Send localized breaking news
• Send notifications to authenticated users
• Send cross-platform notifications to authenticated users

#Dependencies

This project uses:

• Apache HttpComponents.
• Apache Commons Codec.
• Apache Commons IO.]
• Apache Commons Digester.
• Google Gson.

#Status Complete:

• Hub CRUDs
• Registration Mgmt
• Installation Mgmt
• Regular sends
• Scheduled sedns
• Import/Export
• Async operations via Java NIO
• Supported platforms: APNS (iOS), GCM (Android), WNS (Windows Store apps), MPNS(Windows Phone), ADM (Amazon Kindle Fire), Baidu (Android without Google services)

To add:

• Multi-factor authentication support
• Javadocs for bunch of recently implemented features

Caveats:

• Not tested for performance. You can put your own HttpAsyncClient instance to the HttpClientManager if you want to improve connection pooling, adding retry policies and such.