Learn to build a Real-Time Slack clone with AngularFire

Introduction

The goal of this tutorial is to guide you through the creation of a Slack clone called fireSlack. Upon completion, you will learn how to build a real time collaborative chat application using angularFire to integrate Firebase with AngularJS. Your application will be able to provide the following features:

  • Sign up for an account
  • Join/create channels to chat in
  • Have a user profile
  • Direct message other users
  • See who's online

Prerequisites

This course assumes knowledge of programming and at least basic knowledge of JavaScript and AngularJS. We recommend going through A Better Way to Learn AngularJS if you're not familiar with AngularJS. We've created a seed repo based off of the Yeoman AngularJS Generator to help you get started faster. Before you begin, you will need to have Node.js, npm, and Git installed. We'll need Node.js and npm in order to install Grunt and Bower for managing dependencies. Follow these instructions for installing Node.js and npm, and these instructions for installing Git. Additionally, you'll need to have a free Firebase account and create a Firebase for this tutorial.

Final Notes About the Tutorial

You should never copy and paste code from this text unless we tell you to, as we've found that the skills being taught will stick better if you write out all of the code yourself. If you need more clarification on a certain part of the tutorial, we recommend that viewing the supplementary screencast series as we go into far more detail in each of the videos. It's also significantly easier to learn from the screencast series than the text, as you can actually see how a skilled developer manipulates the concepts in AngularJS to build a working application.

Getting Started

Once the initial codebase is cloned locally, we'll need to run a few commands to install dependencies and get our application up and running. Within our codebase, run the following commands:

After running grunt serve, open up http://localhost:4000 and you should see a splash page for our application, with a non-functional login and register page ready for us to build off of. In this tutorial, our directory structure will be grouped by feature (see #1 in this list) and we will be using ui-router as our router. We'll also be using the "controller as" syntax for referencing our controllers.

Authenticating Users using angularFire

Creating a registration and login system for your app can be tedious, but is often one of the most important and required features, and usually requires you to create your own backend. Thankfully, Firebase makes this really easy for us by providing us with a hosted solution.

While you have your Firebase pulled up, keep your Firebase URL handy. It should look something like: https://firebase-name-here.firebaseio.com/

  .constant('FirebaseUrl', 'https://firebase-name-here.firebaseio.com/');

Creating the Auth Service

angular.module('angularfireSlackApp')
  .factory('Auth', function(){

  });

Here we'll inject $firebaseAuth, which is a service that AngularFire provides us with, along with our constant, FirebaseUrl. Then we'll be able to create a reference to Firebase using the Firebase constructor and our FirebaseUrl, which we'll be passing to the $firebaseAuth service. See the angularFire API docs for a list of available methods $firebaseAuth provides. Our factory will return the $firebaseAuth service associated with our Firebase.

The resulting factory should look like this:

angular.module('angularfireSlackApp')
  .factory('Auth', function($firebaseAuth, FirebaseUrl){
    var ref = new Firebase(FirebaseUrl);
    var auth = $firebaseAuth(ref);

    return auth;
  });

Now that we have an Auth service ready for our application to use, let's create a controller to use with our login and registration forms.

Creating the Auth Controller

angular.module('angularfireSlackApp')
  .controller('AuthCtrl', function(Auth, $state){
    var authCtrl = this;

  });

The $state service is provided by ui-router for us to control the state of our application. We can use the go() function on $state to redirect our application to a specific state. We also create a reference to the this keyword within our controller because we're using the controller as syntax. For more information about this syntax, see this lesson.

angular.module('angularfireSlackApp')
  .controller('AuthCtrl', function(Auth, $state){
    var authCtrl = this;

    authCtrl.user = {
      email: '',
      password: ''
    };
  });

This user object will be used with the ng-model directive in our form. Next, we'll need two functions on our controller, one for registering users and one for logging in users. $firebaseAuth provides us with two functions: $authWithPassword for logging in users and $createUser for registering users. Both of these functions take a user object like the one we initialized on our controller, and return a promise. If you're not familiar with how promises work, read this to learn more about promises.

authCtrl.login = function (){
  Auth.$authWithPassword(authCtrl.user).then(function (auth){
    $state.go('home');
  }, function (error){
    authCtrl.error = error;
  });
};

When authentication is successful, we want to send the user to the home state. When it fails, we want to set the error on our controller so we can display the error message to our user.

authCtrl.register = function (){
  Auth.$createUser(authCtrl.user).then(function (user){
    authCtrl.login();
  }, function (error){
    authCtrl.error = error;
  });
};

Our register function works very similarly to our login function. We want to set error on the controller if $createUser fails, however, when $createUser succeeds, it doesn't automatically log in the user that was just created so we'll need to call the login function we just created to log the user in. Now that we have our authentication service and controller created, let's update our templates and put them to use.

<script src="app.js"></script>
<script src="auth/auth.controller.js"></script>
<script src="auth/auth.service.js"></script>
.state('login', {
  url: '/login',
  controller: 'AuthCtrl as authCtrl',
  templateUrl: 'auth/login.html'
})
.state('register', {
  url: '/register',
  controller: 'AuthCtrl as authCtrl',
  templateUrl: 'auth/register.html'
})

The resulting form should look like this:

<form ng-submit="authCtrl.register()">
  <div class="input-group">
    <input type="email" class="form-control" placeholder="Email" ng-model="authCtrl.user.email">
  </div>
  <div class="input-group">
    <input type="password" class="form-control" placeholder="Password" ng-model="authCtrl.user.password">
  </div>
  <input type="submit" class="btn btn-default" value="Register">
</form>
<div ng-show="authCtrl.error">
  <span>{{ authCtrl.error.message }}</span>
</div>

This div will remain hidden until our authentication controller reaches an error, in which case the error message it will get displayed to our user. Next, let's update our login template in a similar fashion.

<form ng-submit="authCtrl.login()">
  <div class="input-group">
    <input type="email" class="form-control" placeholder="Email" ng-model="authCtrl.user.email">
  </div>
  <div class="input-group">
    <input type="password" class="form-control" placeholder="Password" ng-model="authCtrl.user.password">
  </div>
  <input type="submit" class="btn btn-default" value="Log In">
</form>
<div ng-show="authCtrl.error">
  <span>{{ authCtrl.error.message }}</span>
</div>

Now we should have a working register and login system, but we have no way of telling if the user is logged in or not. The login and registration pages are still accessible if we are authenticated. We can resolve this by using the resolve property on our states. resolve allows us to create dependencies that can be injected into controllers or child states. These dependencies can depend on services in our app that return promises, and the promises will get resolved before our controller gets instantiated. Read the ui-router Github Wiki if you're not familiar with how resolve works with ui-router.

resolve: {
  requireNoAuth: function($state, Auth){
    return Auth.$requireAuth().then(function(auth){
      $state.go('home');
    }, function(error){
      return;
    });
  }
}

The $firebaseAuth service provides us with a $requireAuth function which returns a promise. This promise will get resolved with an auth object if the user is logged in. The Firebase Documentation provides a table of what information is available to us within auth. If the user is not authenticated, the promise gets rejected. In our requireNoAuth dependency, if the User is logged in we want to send them back to the home state, otherwise, we need to catch the error that gets thrown and handle it gracefully by returning nothing, allowing the promise to be resolved instead of rejected. Now, we should no longer be able to access the login or register states if we're authenticated.

Storing User Profiles in Firebase

Now that we're able to authenticate users, let's create the ability for users to have custom display names to use in our app (rather than showing the user's email or uid)

angular.module('angularfireSlackApp')
  .factory('Users', function($firebaseArray, $firebaseObject, FirebaseUrl){

    var Users = {};

    return Users;
  });

The purpose of this factory is to provide us with the ability to get either a specific user's data, or to get a list of all of our users. Note that while Firebase provides us with a means of authentication, all of the authentication data is separate from our Firebase data and can't be queried. It is up to us to store any custom user data within Firebase manually.

angular.module('angularfireSlackApp')
  .factory('Users', function($firebaseArray, $firebaseObject, FirebaseUrl){
    var usersRef = new Firebase(FirebaseUrl+'users');

    var Users = {};

    return Users;
  });

Data in Firebase is stored in a tree structure and child nodes can be referenced by adding a path to our FirebaseUrl, so https://firebase-name-here.firebase.io.com/users refers to the users node.

angular.module('angularfireSlackApp')
  .factory('Users', function($firebaseArray, $firebaseObject, FirebaseUrl){
    var usersRef = new Firebase(FirebaseUrl+'users');
    var users = $firebaseArray(usersRef);

    var Users = {};

    return Users;
  });

It's also good to know that while $firebaseArray will return pseudo array, meaning it will act a lot like an array in javascript, however, methods like splice(), push(), pop() will only affect data locally and not on the Firebase. Instead, $firebaseArray provides methods named $add and $remove to provide similar functionality while keeping your data in sync. Read the $firebaseArray Documentation For a complete understanding of how $firebaseArray should be used.

var Users = {
  getProfile: function(uid){
    return $firebaseObject(usersRef.child(uid));
  },
  getDisplayName: function(uid){
    return users.$getRecord(uid).displayName;
  },
  all: users
};

getProfile(uid) allows us to get a $firebaseObject of a specific user's profile, while all returns a $firebaseArray of all the users. getDisplayName(uid) is a helper function that returns a user's displayName when given a uid. We will be keying our data by the uid that comes back from our Firebase auth data, so data in our Firebase will look similar to:

{
  "users": {
    "simplelogin:1":{
      "displayName": "Blake Jackson"
    }
  }
}

Now that our Users service is created, let's create a controller for updating a user's profile. First we'll need to create a new state in app/app.js to resolve a couple dependencies. We want to have the user's auth data and their profile available to us before our controller is instantiated.

.state('profile', {
  url: '/profile',
  resolve: {
    auth: function($state, Users, Auth){
      return Auth.$requireAuth().catch(function(){
        $state.go('home');
      });
    },
    profile: function(Users, Auth){
      return Auth.$requireAuth().then(function(auth){
        return Users.getProfile(auth.uid).$loaded();
      });
    }
  }
})

We left the controller and templateUrl properties out of the state configuration temporarily because we haven't created them yet. The auth dependency is similar to the requireNoAuth dependency we created for login and register, except it does the inverse, where the user is redirected to the home state if they're not authenticated. The .catch function is a shorthand for handling promises if we don't want to provide a success handler. The profile dependency also ensures authentication, but resolves to the user's profile using the getProfile function we created in our Users service. $loaded is a function provided by both $firebaseObject and $firebaseArray that returns a promise that gets resolved when the data from Firebase is available locally.

angular.module('angularfireSlackApp')
  .controller('ProfileCtrl', function($state, md5, auth, profile){
    var profileCtrl = this;
  });

We'll be using Gravatar to get profile picture functionality in our application. Gravatar is a service that provides us with a user's profile picture when given an email, however the email needs to be md5 hashed. Luckily, there are many modules available that can do this for us, and angular-md5 was already included in our seed codebase.

profileCtrl.profile = profile;
profileCtrl.updateProfile = function(){
  profileCtrl.profile.emailHash = md5.createHash(auth.password.email);
  profileCtrl.profile.$save();
};

Here we're getting the current user's email from the auth data that was resolved from our router, hashing it and setting to emailHash on profile. displayName will be set from the template we'll be creating next using ng-model.

getGravatar: function(uid){
  return '//www.gravatar.com/avatar/' + users.$getRecord(uid).emailHash;
},
<script src="auth/auth.service.js"></script>
<script src="users/users.service.js"></script>
<script src="users/profile.controller.js"></script>
url: '/profile',
controller: 'ProfileCtrl as profileCtrl',
templateUrl: 'users/profile.html',
<div class="page-wrapper">

  <div class="page-header">
    <h1>Edit Profile</h1>
  </div>

  <form ng-submit="profileCtrl.updateProfile()">
    <p ng-hide="profileCtrl.profile.displayName">
      You'll need a display name before you can start chatting.
    </p>

    <div class="input-group">
      <input required type="text" class="form-control" placeholder="Display Name" ng-model="profileCtrl.profile.displayName">
    </div>
    <input type="submit" class="btn btn-default" value="Set Display Name">
  </form>

</div>

We should now be able to navigate to http://localhost:4000/#/profile, specify a display name for our user, submit the form and it should persist when we refresh the page.

Creating the Channels Sidebar

Now that our Users can authenticate and have profiles, we can finally start to create the functionality for Channels. We're going to start by creating the left sidebar for listing channels and display the current user's profile.

angular.module('angularfireSlackApp')
  .factory('Channels', function($firebaseArray, FirebaseUrl){
    var ref = new Firebase(FirebaseUrl+'channels');
    var channels = $firebaseArray(ref);

    return channels;
  });
.state('channels', {
  url: '/channels',
  resolve: {
    channels: function (Channels){
      return Channels.$loaded();
    },
    profile: function ($state, Auth, Users){
      return Auth.$requireAuth().then(function(auth){
        return Users.getProfile(auth.uid).$loaded().then(function (profile){
          if(profile.displayName){
            return profile;
          } else {
            $state.go('profile');
          }
        });
      }, function(error){
        $state.go('home');
      });
    }
  }
})

templateUrl and controller are temporarily omitted since we haven't created them yet. We're resolving two dependencies here: channels, which is promising our $firebaseArray of channels, and profile, which is a lot like the profile dependency in the profile state, but we're ensuring that the user already a displayName set, otherwise they're taken to the profile state, and if they're not authenticated, they get sent to the home state.

angular.module('angularfireSlackApp')
  .controller('ChannelsCtrl', function($state, Auth, Users, profile, channels){
    var channelsCtrl = this;
  });
channelsCtrl.profile = profile;
channelsCtrl.channels = channels;
channelsCtrl.getDisplayName = Users.getDisplayName;
channelsCtrl.getGravatar = Users.getGravatar;
channelsCtrl.logout = function(){
  Auth.$unauth();
  $state.go('home');
};
<script src="users/profile.controller.js"></script>
<script src="channels/channels.controller.js"></script>
<script src="channels/channels.service.js"></script>
<div class="main">
  <div class="sidebar">

    <div class="slack-name">
      <h2>FireSlack</h2>
    </div>

    <div class="channel-list">
      <div class="list-head">Channels</div>
    </div>

    <div class="my-info">
      <img class="user-pic" ng-src="{{ channelsCtrl.getGravatar(channelsCtrl.profile.$id) }}" />
      <div class="user-info">
        <div class="user-name">
          {{ channelsCtrl.profile.displayName }}
        </div>

        <div class="options">
          <a ui-sref="profile">edit profile</a>
          /
          <a href="#" ng-click="channelsCtrl.logout()">logout</a>
        </div>
      </div>
    </div>

  </div>
</div>
url: '/channels',
controller: 'ChannelsCtrl as channelsCtrl',
templateUrl: 'channels/index.html',
resolve: {
  requireNoAuth: function($state, Auth){
    return Auth.$requireAuth().then(function(auth){
      $state.go('channels');
    }, function(error){
      return;
    });
  }
}
profileCtrl.updateProfile = function(){
  profileCtrl.profile.emailHash = md5.createHash(auth.password.email);
  profileCtrl.profile.$save().then(function(){
    $state.go('channels');
  });
};

This requireNoAuth dependency is a lot like the one on login and register but it sends the user to the channels state. If you want, you can change the requireNoAuth dependency on login and register to also send the user to the channels state as well. Now when we're logged in and visit http://localhost:4000 we should be sent to the channels state. In that state, we can see the sidebar we just created for our application. There should be the logged in user's name and Gravatar at the bottom of the sidebar, and an edit profile and logout link next to it. We're using the ui-sref directive that comes with ui-router to specify what state we should navigate to on click. If we click on edit profile, we can update the user's displayName and it should send us back to the channels state when we submit the form. The logout link should log us out and send us back to the home state. Now let's create the view to create channels.

.state('channels.create', {
  url: '/create',
  templateUrl: 'channels/create.html',
  controller: 'ChannelsCtrl as channelsCtrl'
})

This state is a child state of the channels controller (the dot notation in the state name specifies parentState.childState). This state will also use ChannelsCtrl. We'll want to render our child states to the right of the sidebar. We need to declare another ui-view tag in order for our child states to appear. You can read more about ui-router's nested states at this Github Wiki.

<div class="message-pane">
  <ui-view></ui-view>
</div>
channelsCtrl.newChannel = {
  name: ''
};
channelsCtrl.createChannel = function(){
  channelsCtrl.channels.$add(channelsCtrl.newChannel).then(function(){
    channelsCtrl.newChannel = {
      name: ''
    };
  });
};

The $add function on the channels $firebaseArray provides similar functionality to the .push() function on a Javascript Array, but keeps our data in sync with Firebase, while returning a promise. Once the new channel is created we'll need to clear out the newChannel object.

<div class="header">
  <h1>Create a channel</h1>
</div>

<form ng-submit="channelsCtrl.createChannel()">
  <div class="input-group">
    <input type="text" class="form-control" placeholder="Channel Name" ng-model="channelsCtrl.newChannel.name">
  </div>
  <input type="submit" class="btn btn-default" value="Create Channel">
</form>
<div class="channel-list">
  <div class="list-head">Channels</div>
  <div class="channel" ng-repeat="channel in channelsCtrl.channels">
    <a># {{ channel.name }}</a>
  </div>
</div>

We're using the ng-repeat directive to iterate over our array of channels.

<div class="channel-list">
  <div class="list-head">Channels</div>
  <div class="channel" ng-repeat="channel in channelsCtrl.channels">
    <a># {{ channel.name }}</a>
  </div>

  <div class="channel create">
    <a ui-sref="channels.create">+ create channel</a>
  </div>
</div>

We're now able to click on the create channel link and start creating channels!

Adding Messaging Functionality

angular.module('angularfireSlackApp')
  .factory('Messages', function($firebaseArray, FirebaseUrl){
    var channelMessagesRef = new Firebase(FirebaseUrl+'channelMessages');

    return {
      forChannel: function(channelId){
        return $firebaseArray(channelMessagesRef.child(channelId));
      }
    };
  });

The forChannel function on our service returns a $firebaseArray of messages when provided a channelId. Later in this tutorial, we'll create a forUsers function for retrieving direct messages.

.state('channels.messages', {
  url: '/{channelId}/messages',
  resolve: {
    messages: function($stateParams, Messages){
      return Messages.forChannel($stateParams.channelId).$loaded();
    },
    channelName: function($stateParams, channels){
      return '#'+channels.$getRecord($stateParams.channelId).name;
    }
  }
})

This state will again be a child state of channels. Our url will have a channelId parameter. We can access this parameter with $stateParams, provided by ui-router. We're resolving messages, which is using the forChannel function from our Messages service, and channelName which we'll be using to display the channel's name in our messages pane. Channel names will be prefixed with a #. The channels dependency we're injecting is coming from the parent state channels since child states inherit their parent's dependencies. We'll come back and add the controller and templateUrl properties once we create our controller and template.

angular.module('angularfireSlackApp')
  .controller('MessagesCtrl', function(profile, channelName, messages){
    var messagesCtrl = this;
  });

Again, the profile dependency that we're injecting will actually come from the parent state channels that resolves to the current user's profile.

messagesCtrl.messages = messages;
messagesCtrl.channelName = channelName;
messagesCtrl.message = '';
messagesCtrl.sendMessage = function (){
  if(messagesCtrl.message.length > 0){
    messagesCtrl.messages.$add({
      uid: profile.$id,
      body: messagesCtrl.message,
      timestamp: Firebase.ServerValue.TIMESTAMP
    }).then(function (){
      messagesCtrl.message = '';
    });
  }
};

A message object will need to contain uid, which will be how we identify who sent the message. body contains the message our user input, and timestamp is a constant from Firebase that tells the Firebase servers to use the their clock for the timestamp. When a message sends successfully, we'll want to clear out messagesCtrl.message so the user can type a new message.

<script src="channels/channels.service.js"></script>
<script src="channels/messages.service.js"></script>
<script src="channels/messages.controller.js"></script>
<div class="header">
  <h1>{{ messagesCtrl.channelName }}</h1>
</div>

<div class="message-wrap" ng-repeat="message in messagesCtrl.messages">
  <img class="user-pic" ng-src="{{ channelsCtrl.getGravatar(message.uid) }}" />
  <div class="message-info">
    <div class="user-name">
      {{ channelsCtrl.getDisplayName(message.uid) }}
      <span class="timestamp">{{ message.timestamp | date:'short' }}</span>
    </div>
    <div class="message">
     {{ message.body }}
    </div>
  </div>
</div>

<form class="message-form" ng-submit="messagesCtrl.sendMessage()">

  <div class="input-group">
    <input type="text" class="form-control" ng-model="messagesCtrl.message" placeholder="Type a message...">
    <span class="input-group-btn">
      <button class="btn btn-default" type="submit">Send</button>
    </span>
  </div>

</form>

Here we're creating a header to display the channelName from our controller. Then we're ng-repeating over messages and using message.uid and the helper functions from channelsCtrl to get the user's display name and Gravatar. We're also using Angular's date filter on the timestamp to display a short timestamp. Finally, at the bottom of our view we have the form for sending messages which submits to the sendMessage function from our controller.

url: '/{channelId}/messages',
templateUrl: 'channels/messages.html',
controller: 'MessagesCtrl as messagesCtrl',
<a ui-sref="channels.messages({channelId: channel.$id})" ui-sref-active="selected"># {{ channel.name }}</a>

We're specifying the parameters for the channels.messages state within the ui-sref directive. The ui-sref-active directive will add the specified class (selected in our case) to the element when a state specified in a sibling or child ui-sref directive. Now we should be able to navigate between channels and start chatting!

channelsCtrl.createChannel = function(){
  channelsCtrl.channels.$add(channelsCtrl.newChannel).then(function(ref){
    $state.go('channels.messages', {channelId: ref.key()});
  });
};

Creating Direct Messages

Now that we have working channels with messaging, adding direct messages will be easier since we can reuse a lot of the existing functionality we have.

    var userMessagesRef = new Firebase(FirebaseUrl+'userMessages')
return {
  forChannel: function(channelId){
    return $firebaseArray(channelMessagesRef.child(channelId));
  },
  forUsers: function(uid1, uid2){
    var path = uid1 < uid2 ? uid1+'/'+uid2 : uid2+'/'+uid1;

    return $firebaseArray(userMessagesRef.child(path));
  }
};

We'll be storing our direct messages in Firebase like so:

{
  "userMessages": {
    "simplelogin:1": {
      "simplelogin:2": {
        "messageId1": {
          "uid": "simplelogin:1",
          "body": "Hello!",
          "timestamp": Firebase.ServerValue.TIMESTAMP
        },
        "messageId2": {
          "uid": "simplelogin:2",
          "body": "Hey!",
          "timestamp": Firebase.ServerValue.TIMESTAMP
        }
      }
    }
  }
}

Since we always want to reference the same path in our Firebase regardless of which id was passed first, we'll need to sort our ids before referencing the direct messages.

.state('channels.direct', {
  url: '/{uid}/messages/direct',
  templateUrl: 'channels/messages.html',
  controller: 'MessagesCtrl as messagesCtrl',
  resolve: {
    messages: function($stateParams, Messages, profile){
      return Messages.forUsers($stateParams.uid, profile.$id).$loaded();
    },
    channelName: function($stateParams, Users){
      return Users.all.$loaded().then(function(){
        return '@'+Users.getDisplayName($stateParams.uid);
      });
    }
  }
});

This state is almost identical to channels.messages, using the same templateUrl and controller. We're using a different url, and the messages dependency is using the Messages.forUsers function that we just created. The channelName dependency also looks up the other user's display name, and prefixes it with @.

channelsCtrl.users = Users.all;
<div class="channel create">
  <a ui-sref="channels.create">+ create channel</a>
</div>

<div class="list-head">Direct Messages</div>
<div class="channel" ng-repeat="user in channelsCtrl.users">
  <a ng-if="user.$id !== channelsCtrl.profile.$id" ui-sref="channels.direct({uid: user.$id})" ui-sref-active="selected">
    {{ user.displayName }}
  </a>
</div>

We're now able to chat directly to other users in our application!

Adding Presence to Users

Having direct messaging is an important feature to any chat application, but it's also very useful to know what users are online. Firebase makes this very easy for us. Read the Firebase Documentation to see some example code using presence. While this code is written using the core Firebase library, we're going to replicate the same functionality using AngularFire.

var usersRef = new Firebase(FirebaseUrl+'users');
var connectedRef = new Firebase(FirebaseUrl+'.info/connected');
setOnline: function(uid){
  var connected = $firebaseObject(connectedRef);
  var online = $firebaseArray(usersRef.child(uid+'/online'));

  connected.$watch(function (){
    if(connected.$value === true){
      online.$add(true).then(function(connectedRef){
        connectedRef.onDisconnect().remove();
      });
    }
  });
}

This function watches for changes at the .info/connected node and will $add any open connections to a $firebaseArray keyed under online within the user's profile. This allows us to track multiple connections (in case the user has multiple browser windows open), which will get removed when the client disconnects.

Users.setOnline(profile.$id);
channelsCtrl.logout = function(){
  channelsCtrl.profile.online = null;
  channelsCtrl.profile.$save().then(function(){
    Auth.$unauth();
    $state.go('home');
  });
};
<div class="user-name">
  <span class="presence" ng-class="{online: channelsCtrl.profile.online}"></span>
  {{ channelsCtrl.profile.displayName }}
</div>

We're also dynamically adding the online class to the span tag using ng-class, based on if the $firebaseArray containing connections in the profile is present.

<a ng-if="user.$id !== channelsCtrl.profile.$id" ui-sref="channels.direct({uid: user.$id})" ui-sref-active="selected">
  <span class="presence" ng-class="{online: user.online}"></span>
  {{ user.displayName }}
</a>

We're now able to see when our users are online! Our application is almost ready for production. In the next sections we will go over securing our data and deploying our application live.

Securing Your Data with Security Rules

When you first create a Firebase, the default security rules allow full read and write access. While this makes it a lot easier to get started developing, it's always strongly recommended that you create security rules to make sure that your data stays consistent and secured. There are three kinds of rules, .read, .write, and .validate for controlling access and validating your data.

{
  "rules":{
    ".read": true,
    "users":{
      "$uid":{
        ".write": "auth !== null && $uid === auth.uid",
        "displayName":{
          ".validate": "newData.exists() && newData.val().length > 0"
        },
        "online":{
          "$connectionId":{
            ".validate": "newData.isBoolean()"
          }
        }
      }
    },
    "channels":{
      "$channelId":{
        ".write": "auth !== null",
        "name":{
          ".validate": "newData.exists() && newData.isString() && newData.val().length > 0"
        }
      }
    },
    "channelMessages":{
      "$channelId":{
        "$messageId":{
          ".write": "auth !== null && newData.child('uid').val() === auth.uid",
          ".validate": "newData.child('timestamp').exists()",
          "body":{
            ".validate": "newData.exists() && newData.val().length > 0"
          }
        }
      }
    },
    "userMessages":{
      "$uid1":{
        "$uid2":{
          "$messageId":{
            ".read": "auth !== null && ($uid1 === auth.uid || $uid2 === auth.uid)",
            ".write": "auth !== null && newData.child('uid').val() === auth.uid",
            ".validate": "$uid1 < $uid2 && newData.child('timestamp').exists()",
            "body":{
              ".validate": "newData.exists() && newData.val().length > 0"
            }
          }
        }
      }
    }
  }
}

Deploying to Firebase

{
  "firebase": "firebase-name-here",
  "public": "dist"
}

firebase deploy may prompt you to log in, but afterwards it should push your application to Firebase's hosting service. Now if you visit https://firebase-name-here.firebaseapp.com/ you should see our completed app, ready for the world to use!