Category Archives: JavaScript

Say What? Live video chat between iOS & WebRTC with Twilio & IBM Watson Cognitive Computing in Real Time

What I’m about to show you might seem like science fiction from the future, but I can assure you it is not. Actually, every piece of this is available for you to use as a service.  Today.

Yesterday Twilio, an IBM partner whose services are available via IBM Bluemix, announced several new SDKs, including live video chat as a service.  This makes live video very easy to integrate into your native mobile or web based applications, and gives you the power to do some very cool things. For example, what if you could add video chat capabilities between your mobile and web clients? Now, what if you could take things a step further, and add IBM Watson cognitive computing capabilities to add real-time transcription and analysis?

Check out this video from yesterday’s Twilio Signal conference keynote, where fellow IBM’ers Damion Heredia and Jeff Sloyer demonstrate exactly this scenario; the integration of the new Twilio video SDK between iOS native and WebRTC client with IBM Watson cognitive computing services providing realtime transcription and sentiment analysis.

If it doesn’t automatically jump to the IBM Bluemix Demo, skip ahead to 2 hours, 15 min, and 20 seconds.

Jeff and Damion did an awesome job showing of both the new video service and the power of IBM Watson. I can also say first-hand that the new Twilio video services are pretty easy to integrate into your own projects (I helped them integrate these services into the native iOS client (physician’s app) shown in the demo)!  You just pull in the SDK, add your app tokens, and instantiate a video chat.   Jeff is pulling the audio stream from the WebRTC client and pushing it up to Watson in real time for the transcription and sentiment analysis services.

Data Management for Apps that Work as Well Offline as They Do Online

Earlier this week I had the privilege of speaking at ApacheCon in Austin, TX on the topic of data management for apps that work as well offline as they do online.  This is an important topic for mobile apps, since, as we all painfully know already, there is never a case when you are always online on your mobile devices.  There always ends up being a time when you need your device/app, but you can’t get online to get the information you need.  Well, this doesn’t always have to be the case. There are strategies you can employ to build apps that work just as well offline as they do online, and the strategy I’d like to highlight today is based upon data management using the IBM Cloudant NoSQL database as a service, which is based upon Apache CouchDB.

Here’s a link to the presentation slides (built using reveal.js) – just use the space bar to advance the presentation slides:

The “couch” in CouchDB is actually an acronym for Cluster of Unreliable Commodity Hardware. At the core of this cluster is the concept of replication, which in the most basic of terms means that  data is shared between multiple sources.  Replication is used to share information between nodes of the cluster, which provides for cluster reliability and fault tolerance.

Replication between Nodes
Replication between Nodes (source)

If you’d like to learn more about replication in Cloudant and CouchDB, you can read more using the links below:

Cloudant is a clustered NoSQL database services that provides an extremely powerful and searchable data store.  It is designed to power the web and mobile apps, and all information is exposed via REST services. Since the IBM Cloudant service is based on CouchDB (and not so coincidentally, IBM is a major contributor to the CouchDB project), replication is also core the the Cloudant service.

With replication, you only have to write your data/changes to a single node in the cluster, and replication takes care of propagating these changes across the cluster.

If you are building apps for the web or mobile, there are options to extend the data replication locally either on the device or in the browser.   This means that you can have a local data store that automatically pushes and/or pulls data from the remote store using replication, and it can be done either via native languages, or using JavaScript.

If you want to have local replication in either a web or hybrid (Cordova/PhoneGap) app, you can use PouchDB.  PouchDB is a local JavaScript database modeled after CouchDB and implements that CouchDB replication API.  So, you can store your data in the browser’s local storage, and those changes will automatically be replicated to the remote Cloudant store.  This works in the browser, in a hybrid (web view) app, or even inside of a Node.js instance. Granted, if you’re in-browser you’ll need to leverage the HTML5 cache to have your app cached locally.

If you are building a native app, don’t worry, you can take advantage of the Cloudant Sync API to leverage the local data store with replication.  This is available for iOS and Android, and implements the CouchDB replication API.

The sample app that I showed in the presentation is a native iOS application based on the GeoPix MobileFirst sample app that I detailed in a previous post.  The difference is that in this case I showed it using the Cloudant Sync API, instead of the MobileFirst data wrapper classes, even though it was pointing at the exact same Cloudant database instance.  You can see a video of the app in action below.

All that you have to do is create a local data store instance, and then use replication to synchronize data between the local store and a remote store.

Replication be either one-way (push or pull), or two-way.  So, any changes between the local and remote stores are replicated across the cluster.  Essentially, the local data store just becomes a node in the cluster.  This provides complete access to the local data, even if there is no network available.  Just save your data to the local store, and replication takes care of the rest.

In the native Objective-C code, you just need to setup the CDTDatastore manager, and initialize your datastore instance.

self.manager = [[CDTDatastoreManager alloc] initWithDirectory:path error:nil];
self.datastore = [self.manager datastoreNamed:@"geopix" error:nil];

Once your datastore is created, you can read/write/modify any data in the local store.  In this case I am creating a generic data object (basically  like a JSON object), and creating a document containing this data.  A document is a record within the data store.

You can add attachments to the document or modify the document as your app needs.  In the code below, I add a JPG atttachment to the document.

//create a document revision
CDTMutableDocumentRevision *rev = [CDTMutableDocumentRevision revision];
rev.body = @{
			 @"sort": [NSNumber numberWithDouble:[now timeIntervalSince1970]],
			 @"clientDate": dateString,
			 @"latitude": [NSNumber numberWithFloat:location.coordinate.latitude],
			 @"longitude": [NSNumber numberWithFloat:location.coordinate.longitude],
			 @"altitude": [NSNumber numberWithFloat:location.altitude],
			 @"course": [NSNumber numberWithFloat:location.course],
			 @"type": @"com.geopix.entry"
			 };

//add the jpg attachment
NSData *imageData = UIImageJPEGRepresentation(image, 0.1);
[imageData writeToFile:imagePath atomically:YES];
 
CDTUnsavedFileAttachment *att1 = [[CDTUnsavedFileAttachment alloc]
								  initWithPath:imagePath
								  name:imageName
								  type:@"image/jpeg"];

rev.attachments = @{ imageName: att1 };

//create a new document from the revision
NSError *error = nil;
CDTDocumentRevision *doc = [self.datastore createDocumentFromRevision:rev error:&error];

if (doc == nil) {
	[logger logErrorWithMessages:@"Error creating document: %@", error.localizedDescription];
}

[logger logDebugWithMessages:@"Document created ID: %@", doc.docId];

Replication is a fire-and-forget process.  You simply need to initialize the replication process, and any changes to the local data store will be replicated to the remote store automatically when the device is online.

//initialize the replicator factory with the local data store manager
CDTReplicatorFactory *replicatorFactory = 
	[[CDTReplicatorFactory alloc] initWithDatastoreManager:self.manager];

NSURL *remoteDatabaseURL = [NSURL URLWithString:REMOTE_DATABASE_URL];

//setup push replication for local->remote changes
NSError *error = nil;
CDTPushReplication *pushReplication = 
	[CDTPushReplication replicationWithSource:self.datastore target:remoteDatabaseURL];

//create the replicator instance
self.replicator = [replicatorFactory oneWay:pushReplication error:&error];
if (!self.replicator) {
	[logger logErrorWithMessages:@"An error occurred: %@", error.localizedDescription];
}

//assign the replicator delegate
self.replicator.delegate = self;

//auto start replication
error = nil;
if (![self.replicator startWithError:&error]) {
	[logger logErrorWithMessages:@"An error occurred: %@", error.localizedDescription];
}

By assigning a replicator delegate class (as shown above), your app can monitor and respond to changes in replication state.  For example, you can update status if replication is in progress, complete, or if an error condition was encountered.

- (void)replicatorDidChangeState:(CDTReplicator *)replicator {
    [logger logDebugWithMessages:@"Replicator changed State: %@", [CDTReplicator stringForReplicatorState:replicator.state]];
}

- (void)replicatorDidChangeProgress:(CDTReplicator *)replicator {
    [logger logDebugWithMessages:@"Replicator progress: %d/%d", replicator.changesProcessed, replicator.changesTotal];
    
    NSDictionary *userInfo = @{ @"status":[NSString stringWithFormat:@"%d/%d", replicator.changesProcessed, replicator.changesTotal] };
    
    [[NSNotificationCenter defaultCenter]
     postNotificationName:@"ReplicationStatus"
     object:self
     userInfo:userInfo];
}

- (void)replicatorDidError:(CDTReplicator *)replicator info:(NSError *)info {
    [logger logErrorWithMessages:@"An error occurred: %@", info.localizedDescription];
    self.replicator = nil;
    
    [[NSNotificationCenter defaultCenter]
     postNotificationName:@"ReplicationError"
     object:self];
}

- (void)replicatorDidComplete:(CDTReplicator *)replicator {
    [logger logDebugWithMessages:@"Replication completed"];
    self.replicator = nil;
    
    [[NSNotificationCenter defaultCenter]
     postNotificationName:@"ReplicationComplete"
     object:self];
}

If you want to access data from the local store, it is always available within the app, regardless of whether or not the device has an active internet connection.  For example, this method will return all documents within the local data store.

-(NSArray*) getLocalData {
    
    NSArray *docs = [self.datastore getAllDocuments];
    return docs;
}

Be sure to review the documentation and/or Cloudant Synch API source code for complete details.

Helpful Links

Video: The Next Generation of Native Apps Built with IBM MobileFirst

Last month I had the opportunity to speak at the DevNexus developer conference in Atlanta on building native iOS apps IBM MobileFirst. DevNexus is a great event, and it is always a privilege to attend – I highly recommend it for next year.   If you weren’t able to make it, no worries!  Most of the sessions were recorded and are available for viewing online via dzone.

The recording of my session is embedded below.  It covers everything you need to know to get started building apps with the MobielFirst platform.

This session focuses mainly on native iOS, but the exact sample concepts apply to MobileFirst apps built for other platforms or hybrid apps.  It covers both the MobileFirst for Bluemix (Cloud) and on-premise MobileFirst Platform Foundation Server solutions.

Here’s the “official” session description:

Once your app goes live in the app store you will have just entered into an iterative cycle of updates, improvements, and releases. Each successively building on features (and defects) from previous versions. IBM MobileFirst Foundation gives you the tools you need to manage every aspect of this cycle, so you can deliver the best possible product to your end user. In this session, we’ll cover the process of integrating a native iOS application with IBM MobileFirst Foundation to leverage all of the capabilities the platform has to offer.

Video originally shared by @dzone.

IBM Watson QA + Speech Recognition + Speech Synthesis = A Conversation With Your Computer

Back in November I released a demo application here on my blog showing the IBM Watson QA Service for cognitive/natural language computing connected to the Web Speech API in Google Chrome to have real conversational interaction with a web application.  It’s a nice demo, but it always drove me nuts that it only worked in Chrome.  Last month the IBM Watson team released 5 new services, and guess what… Speech Recognition and Speech Synthesis are included!

These two services enable you to quickly add Text-To-Speech or Speech-To-Text capability to any application.  What’s a better way to show them off than by updating my existing app to leverage the new speech services?

So here it is: watsonhealthqa.mybluemix.net!

By leveraging the Watson services it can now run in any browser that supports getUserMedia (for speech recognition) and HTML5 <Audio> (for speech playback).

(Full source code available at the bottom of this post)

You can check out a video of it in action below:

If your browser doesn’t support the getUserMedia API or HTML5 <Audio>, then your mileage may vary.  You can check where these features are supported with these links: <Audio>getUserMedia

Warning: This is targeting desktop browsers – HTML5 Audio is a mess on mobile devices due to limited codec support and immature APIs.

So how does this all work?

Just like the QA service, the new Text To Speech and Speech To Text services are now available in IBM Bluemix, so you can create a new application that leverages any of these services, or you can add them to any existing application.

I simply added the Text To Speech and Speech To Text services to my existing Healthcare QA application that runs on Bluemix:

bluemix-dashboard
IBM Bluemix Dashboard

 

These services are available via a REST API. Once you’ve added them to your application, you can consume them easily within any of your applications.

I updated the code from my previous example in 2 ways: 1) take advantage of the Watson Node.js Wrapper that makes interacting with Watson a lot easier and 2) to take advantage of these new services services.

Watson Node.js Wrapper

Using the Watson Node.js Wrapper, you can now easily instantiate Watson services in a single line of code.  For example:

var watson = require('watson-developer-cloud');
var question_and_answer_healthcare = watson.question_and_answer(QA_CREDENTIALS);
var speechToText = watson.speech_to_text(STT_CREDENTIALS);

The credentials come from your environment configuration, then you just create instances of whichever services that you want to consume.

QA Service

The code for consuming a service is now much simpler than the previous version.  When we want to submit a question to the Watson QA service, you can now simply call the “ask” method on the QA service instance.

Below is my server-side code from app.js that accepts a POST submission from the browser, delegates the question to Watson, and takes the result and renders HTML using a Jade template. See the Getting Started Guide for the Watson QA Service to learn more about the wrappers for Node or Java.

// Handle the form POST containing the question
app.post('/ask', function(req, res){

    // delegate to Watson
    question_and_answer_healthcare.ask({ text: req.body.questionText}, function (err, response) {
        if (err)
            console.log('error:', err);
        else {
          var response = extend({ 'answers': response[0] },req.body);

          // render the template to HTML and send it to the browser
          return res.render('response', response);
        }
    });
});

Compare this to the previous version, and you’ll quickly see that it is much simpler.

Speech Synthesis

At this point, we already have a functional service that can take natural language text, submit it to Watson,  and return a search result as text.  The next logical step for me was to add speech synthesis using the Watson Text To Speech Service (TTS).  Again, the Watson Node Wrapper and Watson’s REST services make this task very simple.  On the client side you just need to set the src of an <audio> instance to the URL for the TTS service:

<audio controls="" autoplay="" src="/synthesize?text=The text that should generate the audio goes here"></audio>

On the server you just need to synthesize the audio from the data in the URL query string.  Here’s an example how to invoke the text to speech service directly from the Watson TTS sample app:

var textToSpeech = new watson.text_to_speech(credentials);

// handle get requests
app.get('/synthesize', function(req, res) {

  // make the request to Watson to synthesize the audio file from the query text
  var transcript = textToSpeech.synthesize(req.query);

  // set content-disposition header if downloading the
  // file instead of playing directly in the browser
  transcript.on('response', function(response) {
    console.log(response.headers);
    if (req.query.download) {
      response.headers['content-disposition'] = 'attachment; filename=transcript.ogg';
    }
  });

  // pipe results back to the browser as they come in from Watson
  transcript.pipe(res);
});

The Watson TTS service supports .ogg and .wav file formats.  I modified this sample is setup only with .ogg files.  On the client side, these are played using the HTML5 <audio> tag.

Speech Recognition

Now that we’re able to process natural language and generate speech, that last part of the solution is to recognize spoken input and turn it into text.  The Watson Speech To Text (STT) service handles this for us.  Just like the TTS service, the Speech To Text service also has a sample app, complete with source code to help you get started.

This service uses the browser’s getUserMedia (streaming) API with socket.io on Node to stream the data back to the server with minimal latency. The best part is that you don’t have to setup any of this on your own. Just leverage the code from the sample app. Note: the getUserMedia API isn’t supported everywhere, so be advised.

On the client side you just need to create an instance of the SpeechRecognizer class in JavaScript and handle the result:

var recognizer = new SpeechRecognizer({
  ws: '',
  model: 'WatsonModel'
});

recognizer.onresult = function(data) {

    //get the transcript from the service result data
    var result = data.results[data.results.length-1];
    var transcript = result.alternatives[0].transcript;

    // do something with the transcript
    search( transcript, result.final );
}

On the server, you need to create an instance of the Watson Speech To Text service, and setup handlers for the post request to receive the audio stream.

// create an instance of the speech to text service
var speechToText = watson.speech_to_text(STT_CREDENTIALS);

// Handle audio stream processing for speech recognition
app.post('/', function(req, res) {
    var audio;

    if(req.body.url && req.body.url.indexOf('audio/') === 0) {
        // sample audio stream
        audio = fs.createReadStream(__dirname + '/../public/' + req.body.url);
    } else {
        // malformed url
        return res.status(500).json({ error: 'Malformed URL' });
    }

    // use Watson to generate a text transcript from the audio stream
    speechToText.recognize({audio: audio, content_type: 'audio/l16; rate=44100'}, function(err, transcript) {
        if (err)
            return res.status(500).json({ error: err });
        else
            return res.json(transcript);
    });
});

Source Code

You can interact with a live instance of this application at watsonhealthqa.mybluemix.net, and complete client and server side code is available at github.com/triceam/IBMWatson-QA-Speech.

Just setup your Bluemix app, clone the sample code, run NPM install and deploy your app to Bluemix using the Cloud Foundry CLI.

Helpful Links

GeoPix: A sample iOS app powered by IBM MobileFirst for Bluemix

In this post I’d like to show a fairly simple application that I put together which shows off some of the rich capabilities for IBM MobileFirst for Bluemix that you get out of the box – All with an absolute minimal amount of your own developer effort.  Bluemix, of course, being IBM’s platform as a service offering.

GeoPix is a sample application leveraging IBM MobileFirst for Bluemix to capture data and images on a mobile device, persist that data locally (offline), and replicate that data to the cloud. Since it’s built with IBM MobileFirst, we get lots of things out of the box, including operational analytics, user authentication, and much more.

(full source code at the bottom of this post)

Here’s what the application currently does:

  • User can take a picture or select an image from the device
  • App captures geographic location when the image is captured
  • App saves both the image and metadata to a local data store on the device.
  • App uses asynchronous replication to automatically save any data in local store up to the remote store whenever the network is available
  • Oh yeah, can’t forget, the user auth is via Facebook
  • MobileFirst provides all the analytics we need.  Bluemix provides the cloud based server and Cloudant NoSQL data store.
  • All captured data is available on a web based front-end powered by Node.js

Here’s a video of it in action:

… and you can check out the web interface at geopix.mybluemix.net.

(full source code at the bottom of this post)

This is powered by the iOS 8 MobileFirst application boilerplate on Bluemix.  With this application template you can have your backend infrastructure setup within minutes, and it includes:

  • User authentication
  • Usage/operational analytics
  • Cloudant NoSQL DB
  • Simplified Push Notifications
  • Node.js backend

In this sample I’m using everything but the Push Notifications service.  I’m using user authentication, the Cloudant DB (offline/local store and remote/cloud store), and the node.js backend.  You get the operational analytics automatically.

To get started, you just need to create a new iOS 8 mobile application on Bluemix.  See my video series on Getting Started with IBM MobileFirst for Bluemix for a complete walkthrough of creating a new app using MobileFirst for Bluemix, or check out the Getting Started Guide in the official docs.

You need to initialize your app, and make sure you have setup the Facebook identity provider.  You can create your Facebook authentication at https://developers.facebook.com/.  Once the user is authenticated, the client app is fully functional.

The app UI is very simple, basically just two buttons for capturing images (the last captured image shows up in the background):

App's main UI
App’s main UI

There’s also a gallery for viewing local images:

Local gallery view
Local gallery view

Capturing Location

Capturing data is very straightforward.  The geographic location is captured using Apple’s Core Location framework.  We just need to implement the CLLocationManagerDelegate protocol:

- (void)locationManager:(CLLocationManager *)manager
 didUpdateLocations:(NSArray *)locations {

    self.currentLocation = [locations lastObject];
    NSDate* eventDate = self.currentLocation.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
    if (abs(howRecent) < 15.0) {
    // If the event is recent, do something with it.
    locationLabel.text = [NSString stringWithFormat:@" Lat: %+.5f, Lon: %+.5f\n",
      self.currentLocation.coordinate.latitude,
      self.currentLocation.coordinate.longitude];
    }
}

Then initialize CLLocationManager using our class as the location manager’s delegate:

if (self.locationManager == nil)
  self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
self.locationManager.pausesLocationUpdatesAutomatically = YES;

Capturing Images

Capturing images from the device is also very straightforward.  In the app I leverage Apple’s UIImagePickerController to allow the user to either upload an existing image or capture a new image.  See the presentImagePicker and didFinishPickingMediaWithInfo below. All of this standard practice using Apple’s developer SDK:

- (void) presentImagePicker:(UIImagePickerControllerSourceType) sourceType {
 if ( sourceType == UIImagePickerControllerSourceTypeCamera  && ![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
  [logger logErrorWithMessages:@"device has no camera"];
  UIAlertView *myAlertView = [[UIAlertView alloc] initWithTitle:@"Error"
                 message:@"Device has no camera"
                delegate:nil
             cancelButtonTitle:@"OK"
             otherButtonTitles: nil];
  [myAlertView show];
 };

 if ( sourceType != UIImagePickerControllerSourceTypeCamera || [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] ){
  UIImagePickerController *picker = [[UIImagePickerController alloc] init];
  picker.delegate = self;
  picker.allowsEditing = NO;
  picker.sourceType = sourceType;

  [self presentViewController:picker animated:YES completion:NULL];
 }
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

 [logger logDebugWithMessages:@"didFinishPickingMediaWithInfo"];
 UIImage *image = info[UIImagePickerControllerOriginalImage];
 currentImage.image = image;
 [[DataManager sharedInstance] saveImage:image withLocation:self.currentLocation];
 [picker dismissViewControllerAnimated:YES completion:nil];
}

Persisting Data

If you notice in the didFinishPickingMediaWithInfo method above, there is a call to the DataManager’s saveImage withLocation method. This is where we save data locally and rely on Cloudant’s replication to automatically save data from the local data store up to the Cloudant NoSQL database.  This is powered by the iOS 8 Data service from Bluemix.

The first thing that we will need to do is initialize the local and remote data stores. Below you can see my init method from my DataManager class. In this, you can see the local data store is initialized, then the remote data store is initialized. If either data store already exists, the existing store will be used, otherwise it is created.

-(id) init {
 self = [super init];

 if ( self ) {
  logger = [IMFLogger loggerForName:NSStringFromClass([self class])];
  [logger logDebugWithMessages:@"initializing local datastore 'geopix'..."];

  // initialize an instance of the IMFDataManager
  self.manager = [IMFDataManager sharedInstance];

  NSError *error = nil;
  //create a local data store
  self.datastore = [self.manager localStore:@"geopix" error:&error];

  if (error) {
   [logger logErrorWithMessages:@"Error creating local data store %@",error.description];
  }

  //create a remote data store
  [self.manager remoteStore:@"geopix" completionHandler:^(CDTStore *store, NSError *error) {
   if (error) {
    [logger logErrorWithMessages:@"Error creating remote data store %@",error.description];
   } else {
    [self.manager setCurrentUserPermissions:DB_ACCESS_GROUP_MEMBERS forStoreName:@"geopix" completionHander:^(BOOL success, NSError *error) {
     if (error) {
      [logger logErrorWithMessages:@"Error setting permissions for user with error %@",error.description];
     }

     [self replicate];
    }];
   }
  }];

  //start replication
  [self replicate];
 }

 return self;
} 

Once the data stores are created, you can see that the replicate method is invoked.  This starts up the replication process to automatically push changesfrom the local data store to the remote data store “in the cloud”.

Therefore, if you’re collecting data when the app is offline, then you have nothing to worry about.  All of the data will be stored locally and pushed up to the cloud whenever you’re back online – all with no additional effort on your part.  When using replication with the Cloudant SDK, you just have to start the replication process and let it do it’s thing… fire and forget.

In my replicate function, I setup CDTPushReplication for pushing changes to the remote data store.  You could also setup two-way replication to automatically pull new changes from the remote store.

-(void) replicate {
 if ( self.replicator == nil ) {
  [logger logDebugWithMessages:@"attempting replication to remote datastore..."];

  __block NSError *replicationError;
  CDTPushReplication *push = [self.manager pushReplicationForStore: @"geopix"];
  self.replicator = [self.manager.replicatorFactory oneWay:push error:&replicationError];
  if(replicationError){
   // Handle error
   [logger logErrorWithMessages:@"An error occurred: %@", replicationError.localizedDescription];
  }

  self.replicator.delegate = self;

  replicationError = nil;
  [logger logDebugWithMessages:@"starting replication"];
  [self.replicator startWithError:&replicationError];
  if(replicationError){
   [logger logErrorWithMessages:@"An error occurred: %@", replicationError.localizedDescription];
  }else{
   [logger logDebugWithMessages:@"replication start successful"];
  }
 }
 else {
  [logger logDebugWithMessages:@"replicator already running"];
 }
}

Once we’ve setup the remote and local data stores and setup replication, we now are ready to save the data the we’re capturing within our app.

Next is my saveImage withLocation method.  Here you can see that it creates a new CDTMutableDocumentRevision object (this is a generic object for the Cloudant NoSQL database), and populates it with the location data and timestamp.   It then creates a jpg image from the UIImage (passed in from the UIImagePicker above) and adds the jpg as an attachment to the document revision.  Once the document is created, it is saved to the local data store.   We then let replication take care of persisting this data to the back end.

-(void) saveImage:(UIImage*)image withLocation:(CLLocation*)location {

 [logger logDebugWithMessages:@"saveImage withLocation"];

 //save in background thread
 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^(void) {

  [logger logDebugWithMessages:@"creating document..."];

  NSDate *now = [NSDate date];
  NSString *dateString = [NSDateFormatter localizedStringFromDate:now
                 dateStyle:NSDateFormatterShortStyle
                 timeStyle:NSDateFormatterFullStyle];

  // Create a document
  CDTMutableDocumentRevision *rev = [CDTMutableDocumentRevision revision];
  rev.body = @{
      @"sort": [NSNumber numberWithDouble:[now timeIntervalSince1970]],
      @"clientDate": dateString,
      @"latitude": [NSNumber numberWithFloat:location.coordinate.latitude],
      @"longitude": [NSNumber numberWithFloat:location.coordinate.longitude],
      @"altitude": [NSNumber numberWithFloat:location.altitude],
      @"course": [NSNumber numberWithFloat:location.course],
      @"type": @"com.geopix.entry"
      };

  [logger logDebugWithMessages:@"creating image attachment..."];

  NSDate *date = [NSDate date];
  NSString *imageName = [NSString stringWithFormat:@"image%f.jpg", [date timeIntervalSince1970]];

  NSString *tempDirectory = NSTemporaryDirectory();
  NSString *imagePath = [tempDirectory stringByAppendingPathComponent:imageName];

  [logger logDebugWithMessages:@"saving image to temporary location: %@", imagePath];

  NSData *imageData = UIImageJPEGRepresentation(image, 0.1);
  [imageData writeToFile:imagePath atomically:YES];

  CDTUnsavedFileAttachment *att1 = [[CDTUnsavedFileAttachment alloc]
            initWithPath:imagePath
            name:imageName
            type:@"image/jpeg"];

  rev.attachments = @{ imageName: att1 };

  [self.datastore save:rev completionHandler:^(id savedObject, NSError *error) {
   if(error) {
    [logger logErrorWithMessages:@"Error creating document: %@", error.localizedDescription];
   }
   [logger logDebugWithMessages:@"Document created: %@", savedObject];
  }];

  [self replicate];
 });
}

If we want to query data from either the remote or local data stores, we can just use the performQuery method on the data store. Below you can see a method for retrieving data for all of the images in the local data store.

-(void) getLocalData:(void (^)(NSArray *results, NSError *error)) completionHandler {

 NSPredicate *queryPredicate = [NSPredicate predicateWithFormat:@"(type = 'com.geopix.entry')"];
 CDTCloudantQuery *query = [[CDTCloudantQuery alloc] initWithPredicate:queryPredicate];

 [self.datastore performQuery:query completionHandler:^(NSArray *results, NSError *error) {

  completionHandler( results, error );
 }];
}

At this point we’ve now captured an image, captured the geographic location, saved that data in our local offline store, and then use replication to save that data up to the cloud whenever it is available.

AND…

We did all of this without writing a single line of server-side logic.   Since this is built on top of MobileFirst for Bluemix, all the backend infrastructure is setup for us, and we get operational analytics to monitor everything that is happening.

With the operational analytics we get:

  • App usage
  • Active Devices
  • Network Usage
  • Authentications
  • Data Storage
  • Device Logs (yes, complete debug/crash logs from devices out in the field)
  • Push Notification Usage

Sharing on the web

Up until this point we haven’t had to write any back-end code. However the mobile app boilerplate on Bluemix comes with a Node.js server.  We might as well take advantage of it.

I exposed the exact same data captured within the app on the Node.js service, which you can see at http://geopix.mybluemix.net/.

Web UI
Web UI

The Node.js back end comes preconfigured to leverage the express.js framework for building web applications.  I added the jade template engine and Leaflet for web-mapping, and was able to crank this out ridiculously quickly.

The first thing we need to do is make sure  we have our configuration variables for accessing the Cloudant service from our node app.  These are environment vars that you get automatcilly if you’re running on Bluemix, but you need to set these for your local dev environment:

var credentials = {};

if (process.env.hasOwnProperty("VCAP_SERVICES")) {
 // Running on Bluemix. Parse out the port and host that we've been assigned.
 var env = JSON.parse(process.env.VCAP_SERVICES);
 var host = process.env.VCAP_APP_HOST;
 var port = process.env.VCAP_APP_PORT;

 credentials = env['cloudantNoSQLDB'][0].credentials;
}
else {

 //for local node.js server instance
 credentials.username = "cloudant username here";
 credentials.password = "cloudant password here";
 credentials.url = "cloudant url here";
}

Next we’ll add our URL/content mappings:

app.get('/', function(req, res){
  prepareData(res, 'map');
});

app.get('/list', function(req, res){
  prepareData(res, 'list');
});

Next you’ll se the logic for querying the Cloudant data store and preparing the data for our UI templates. You can customize this however you want – caching for performance, refactoring for abstraction, or whatever you want. All interactions with Cloudant are powered by the Cloudant Node.js Client

var prepareData = function(res, template) {
 var results = [];

 //create the index if it doesn't already exist
 var sort_index = {name:'sort', type:'json', index:{fields:['sort']}};
 geopix.index(sort_index, function(er, response) {
  if (er) {
   throw er;
  }

  //perform the search
  //we're just pulling back all
  //data captured ("sort" will be numeric)
  var selector = {sort:{"$gt":0}};
  geopix.find({selector:selector, sort:["sort"]}, function(er, result) {
   if (er) {
    throw er;
   }

   //prepare data for template
   for (var x=0; x<result.docs.length; x++) {
    var obj = result.docs[x];

    for (var key in obj._attachments) {
     obj.image = credentials.url + "/" + database + "/" + obj._id +"/" + key;
     break;
    }

    results.push( obj );
   }
   res.render(template, { results:results});
  });
 });
};

After the prepareData method has prepared data for formatting in the UI, the template is rendered by invoking Jade’s render method:

res.render(template, { results:results});

This will render whichever template was passed in – I have two: map.jade (the map template) and list.jade (the list template). You can check out the list template below, and see it in action here: http://geopix.mybluemix.net/list

html
  head
 title GeoPix - powered by Bluemix
 link(href='//maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css' rel='stylesheet')
 link(href='/public/css/index.css' rel='stylesheet')
 meta(name="viewport" content="width=device-width, initial-scale=1")
  body
 div(class='well')
  h1 GeoPix - Powered by Bluemix
  p
   a(href='/') Map
   &nbsp;|&nbsp;
   a(href='/list') List
 div(class="container-fluid")
  each val, index in results
   div(class="col-md-6")
    div(class="panel panel-default")
     div(class="panel-heading")
      h3= val.clientDate
     div(class="panel-body")
      img(src=val.image)
      p= 'latitude: ' + val.latitude + ", longitude:" + val.longitude + ", altitude:" + val.altitude

In the map view I used the Leaflet map engine and Open Street Map data, along with the Leaflet Marker Cluster plugin for displaying clustered results.

Source Code

You can check out the web interface live at: http://geopix.mybluemix.net/.  If you want to setup the environment on your own, you can grab the complete source code at:

Helpful Links

Ready to start building your own apps on IBM Bluemix?  Just head over to http://bluemix.net and get a free developer trial today!