Real-World Angular Series - Part 2: Authentication and Data Modeling

TL;DR: This 8-part tutorial series covers building and deploying a full-stack JavaScript application from the ground up with hosted MongoDB, Express, Angular, and Node.js (MEAN stack). The completed code is available in the mean-rsvp-auth0 GitHub repo and a deployed sample app is available at https://rsvp.kmaida.net. Part 2 of the tutorial series covers authentication, authorization, and data modeling.

Real-World Angular Series

You can view all sections of the tutorial series here:

1. Real-World Angular Series - Part 1: MEAN Setup & Angular Architecture
2. Real-World Angular Series - Part 2: Authentication and Data Modeling (you are here!)
3. Real-World Angular Series - Part 3: Fetching and Displaying API Data
4. Real-World Angular Series - Part 4: Access Management, Admin, and Detail Pages
5. Real-World Angular Series - Part 5: Animation and Template-Driven Forms
6. Real-World Angular Series - Part 6: Reactive Forms and Custom Validation
7. Real-World Angular Series - Part 7: Relational Data and Token Renewal
8. Real-World Angular Series - Part 8: Lazy Loading, Production Deployment, SSL

Part 2: Authentication and Data Modeling

The first part of this tutorial covered how to set up the cloud-hosted MongoDB database, Node server, and front end for our real-world Angular application.

The second installment in the series covers authentication, authorization, feature planning, and data modeling.

1. Angular: Authentication
2. Admin Authorization
3. Planning App Features
4. Data Modeling

Angular: Authentication

Let's pick up right where we left off last time. We've built the main layout for our app. Now it's time to add an authentication feature. Our app's basic authentication should include:

• Login and logout
• User profile and token management
• Session persistence
• Authorization of HTTP requests with access token

Install Auth0.js

First let's install a new dependency. We need the auth0-js package to interface with our Auth0 account. Install this package with npm from the project root:

$ npm install auth0-js@latest --save

Dynamic Environment Configuration

Let's create a file to store information about our app's environment. We're currently developing on localhost:4200, but the app will be deployed on the Node server eventually, and in production, it will run on a reverse proxy. We'll need to make sure our development environment doesn't break our production environment and vice versa.

Create a folder: src/app/core, then add a file there called env.config.ts:

// src/app/core/env.config.ts
const _isDev = window.location.port.indexOf('4200') > -1;
const getHost = () => {
  const protocol = window.location.protocol;
  const host = window.location.host;
  return `${protocol}//${host}`;
};
const apiURI = _isDev ? 'http://localhost:8083/api/' : `/api/`;

export const ENV = {
  BASE_URI: getHost(),
  BASE_API: apiURI
};

This code detects the host environment and sets the app's base URI and base API URI. We'll import this ENV configuration wherever we need to detect and use these URIs.

Note: Another way to do this would be to set up your environments/environment.*.ts files with environment-dependent settings. In our app, we will allow this to be generated dynamically based on the URL, but feel free to use the environment.*.ts files instead if you prefer.

Authentication Configuration

We'll store our Auth0 authentication configuration in an auth.config.ts file. Create the following blank file: src/app/auth/auth.config.ts.

Open this file and customize the following code with your own Auth0 client and API information:

// src/app/auth/auth.config.ts
import { ENV } from './../core/env.config';

interface AuthConfig {
  CLIENT_ID: string;
  CLIENT_DOMAIN: string;
  AUDIENCE: string;
  REDIRECT: string;
  SCOPE: string;
};

export const AUTH_CONFIG: AuthConfig = {
  CLIENT_ID: '[AUTH0_CLIENT_ID]',
  CLIENT_DOMAIN: '[AUTH0_CLIENT_DOMAIN]', // e.g., you.auth0.com
  AUDIENCE: '[YOUR_AUTH0_API_AUDIENCE]', // e.g., http://localhost:8083/api/
  REDIRECT: `${ENV.BASE_URI}/callback`,
  SCOPE: 'openid profile'
};

Important Note: Make sure you copy the configuration properties exactly as they appear in your Auth0 Dashboard settings. If identifiers are not exact, authentication will not and should not function.

Authentication Service

Authentication logic on the front end will be handled with an AuthService authentication service. Let's generate the boilerplate for a new service with the CLI:

$ ng g service auth/auth

Now open the generated auth.service.ts file and add the necessary code to our authentication service:

// src/app/auth/auth.service.ts
import { Injectable } from '@angular/core';
import { Router } from '@angular/router';
import { BehaviorSubject } from 'rxjs';
import { AUTH_CONFIG } from './auth.config';
import * as auth0 from 'auth0-js';

@Injectable()
export class AuthService {
  // Create Auth0 web auth instance
  private _auth0 = new auth0.WebAuth({
    clientID: AUTH_CONFIG.CLIENT_ID,
    domain: AUTH_CONFIG.CLIENT_DOMAIN,
    responseType: 'token',
    redirectUri: AUTH_CONFIG.REDIRECT,
    audience: AUTH_CONFIG.AUDIENCE,
    scope: AUTH_CONFIG.SCOPE
  });
  accessToken: string;
  userProfile: any;
  expiresAt: number;
  // Create a stream of logged in status to communicate throughout app
  loggedIn: boolean;
  loggedIn$ = new BehaviorSubject<boolean>(this.loggedIn);
  loggingIn: boolean;

  constructor(private router: Router) {
    // If app auth token is not expired, request new token
    if (JSON.parse(localStorage.getItem('expires_at')) > Date.now()) {
      this.renewToken();
    }
  }

  setLoggedIn(value: boolean) {
    // Update login status subject
    this.loggedIn$.next(value);
    this.loggedIn = value;
  }

  login() {
    // Auth0 authorize request
    this._auth0.authorize();
  }

  handleAuth() {
    // When Auth0 hash parsed, get profile
    this._auth0.parseHash((err, authResult) => {
      if (authResult && authResult.accessToken) {
        window.location.hash = '';
        this._getProfile(authResult);
      } else if (err) {
        console.error(`Error authenticating: ${err.error}`);
      }
      this.router.navigate(['/']);
    });
  }

  private _getProfile(authResult) {
    this.loggingIn = true;
    // Use access token to retrieve user's profile and set session
    this._auth0.client.userInfo(authResult.accessToken, (err, profile) => {
      if (profile) {
        this._setSession(authResult, profile);
      } else if (err) {
        console.warn(`Error retrieving profile: ${err.error}`);
      }
    });
  }

  private _setSession(authResult, profile?) {
    this.expiresAt = (authResult.expiresIn * 1000) + Date.now();
    // Store expiration in local storage to access in constructor
    localStorage.setItem('expires_at', JSON.stringify(this.expiresAt));
    this.accessToken = authResult.accessToken;
    this.userProfile = profile;
    // Update login status in loggedIn$ stream
    this.setLoggedIn(true);
    this.loggingIn = false;
  }

  private _clearExpiration() {
    // Remove token expiration from localStorage
    localStorage.removeItem('expires_at');
  }

  logout() {
    // Remove data from localStorage
    this._clearExpiration();
    // End Auth0 authentication session
    this._auth0.logout({
      clientId: AUTH_CONFIG.CLIENT_ID,
      returnTo: ENV.BASE_URI
    });
  }

  get tokenValid(): boolean {
    // Check if current time is past access token's expiration
    return Date.now() < JSON.parse(localStorage.getItem('expires_at'));
  }

  renewToken() {
    // Check for valid Auth0 session
    this._auth0.checkSession({}, (err, authResult) => {
      if (authResult && authResult.accessToken) {
        this._getProfile(authResult);
      } else {
        this._clearExpiration();
      }
    });
  }

}

This service uses the config variables from auth.config.ts to instantiate an auth0.js WebAuth instance.

An RxJS BehaviorSubject is used to provide a stream of authentication status events that we can subscribe to anywhere in the app.

The constructor checks the app authentication status upon initialization. If the user has not logged out of our Angular app from a previous session (their token has not expired), we'll call a method called renewToken() to verify that their Auth0 session on the authentication server is also still valid. If it is, we'll receive a fresh access token.

Note: The Angular app's authentication lifespan is not the same thing as the authentication session on the server. We manage the Angular app authentication with the expiration of the JWT access token, and the persistence or removal of this tells us whether or not to ask the server if the user's Auth0 authentication session is still valid when initializing the app.

The login() method authorizes the authentication request with Auth0 using the auth config variables. The Auth0 login page will be shown to the user and they can then log in.

Note: If it's the user's first visit to our app and our callback is on localhost, they'll also be presented with a consent screen where they can grant access to our API. A first party client on a non-localhost domain would be highly trusted, so the consent dialog would not be presented in this case. You can modify this by editing your Auth0 Dashboard API Settings. Look for the "Allow Skipping User Consent" toggle.

We'll receive an an access_token and a time until token expiration (expiresIn) from Auth0 when returning to our app. The handleAuth() method uses Auth0's parseHash() method callback to get the user's profile (_getProfile()) and set the session (_setSession()) by saving the tokens, expiration, and profile to local storage and calling setLoggedIn() so that any components in the app are informed that the user is now authenticated.

Next we'll create a little helper method to easily clear the expiration from local storage, since we will need to do this in multiple places.

We'll define a logout() method that clears expiration and then calls the Auth0 logout() method to officially end the user's Auth0 authentication session. This performs a redirect back to the URL we specify (in this case, our app's public homepage).

We also have a tokenValid() accessor to check whether the current datetime is less than the token expiration datetime.

Finally, we'll implement the renewToken() method, which uses the Auth0 checkSession() method to request a fresh access token from Auth0 if the user's authentication session is still active. If there is no session active, we won't take any action. We don't want to produce any errors or logs here because having no session does not mean anything went wrong, it just tells us the user should not be automatically and silently logged back into the Angular app.

Provide AuthService in App Module

In order to use the AuthService methods and properties anywhere in our app, we need to add the service to the providers array in our app.module.ts:

// src/app/app.module.ts
...
import { AuthService } from './auth/auth.service';
...
@NgModule({
  ...
  providers: [
    ...,
    AuthService
  ],
  ...
})
...

Create a Callback Component

Next we'll create a Callback component. This is where the app is redirected after authentication. This component handles the authentication information and then shows a loading message until hash parsing is completed and the Angular app redirects back to the home page.

Note: Recall that we already added http://localhost:4200/callback and http://localhost:8083/callback to our Auth0 Client Allowed Callback URLs setting.

Let's generate this component with the Angular CLI:

$ ng g component pages/callback

The authentication service's handleAuth() method must be called in the callback.component.ts constructor so it will run on initialization of our app:

// src/app/pages/callback/callback.component.ts
import { AuthService } from './auth/auth.service';
...
  constructor(private auth: AuthService) {
    // Check for authentication and handle if hash present
    auth.handleAuth();
  }
...

All we need to do in this component's template is change the text in callback.component.html to Loading..., like so:

<!-- src/app/pages/callback/callback.component.html -->
<div>
  Loading...
</div>

We'll spruce this up later with a nice loading icon. For now, let's add the component to our routing module, app-routing.module.ts:

// src/app/app-routing.module.ts
...
import { CallbackComponent } from './pages/callback/callback.component';

const routes: Routes = [
  ...
  {
    path: 'callback',
    component: CallbackComponent
  }
];
...

Add Login and Logout to Header Component

Now we have the logic necessary to authenticate users, but we still need a way for them to log in and out in the UI. Let's add this in the Header component.

Open up the header.component.ts file:

// src/app/header/header.component.ts
...
import { AuthService } from './../auth/auth.service';
...
export class HeaderComponent implements OnInit {
  ...
  constructor(
    ...,
    public auth: AuthService) { }
  ...
}

We'll import our AuthService and declare it in the constructor function.

Note: We're using public because the authentication service's methods will be used in the template, not just in the class.

Now let's add login, logout, and a user greeting to the header.component.html template:

<!-- src/app/header/header.component.html -->
<header id="header" class="header">
  <div class="header-page bg-primary">
    ...
    <div class="header-page-authStatus">
      <span *ngIf="auth.loggingIn">Logging in...</span>
      <ng-template [ngIf]="!auth.loggingIn">
        <a *ngIf="!auth.loggedIn" (click)="auth.login()">Log In</a>
        <span *ngIf="auth.loggedIn && auth.userProfile">
          {{ auth.userProfile.name }}
          <span class="divider">|</span>
          <a (click)="auth.logout()">Log Out</a>
        </span>
      </ng-template>
    </div>
  ...

We've added a <div class="header-page-authStatus> element. In order to prevent a flash of content while our service is busy processing a new login, we'll use the ngIf directive to show "Logging in..." if our auth.loggingIn property is true. We'll then use ngIf again with the loggedIn property to determine if the user is logged in to show or hide the appropriate markup. If the user is not logged in, we'll show a "Log In" link. If they're already authenticated, we'll show their name and a link to log out.

Now let's add a little bit of CSS to style our new authentication status elements. Open the header.component.scss file:

/* src/app/header/header.component.scss */
...
.header-page {
  ...
  &-authStatus {
    color: #fff;
    font-size: 12px;
    line-height: 50px;
    padding: 0 10px;
    position: absolute;
      right: 0; top: 0;

    a:hover {
      text-decoration: underline;
    }
    .divider {
      display: inline-block;
      opacity: .5;
      padding: 0 4px;
    }
  }
}

We can now log into our app! Try it out in the browser by clicking the "Log In" link and authenticating. You should see the Auth0 login page like so:

Once logged in, you should see your name and a link to log out in the upper right corner of the header.

You should also be able to close the browser and reopen it to find your login status has persisted (unless enough time has passed for the token to expire, or you clicked the "Log Out" link).

Admin Authorization

For our RSVP app, only users with admin privileges should be able to create, edit, and delete events. All other users will only be able to RSVP to these events. In order to implement this, we'll need to assign and then utilize user roles in both our Node.js API and our Angular app.

First, let's take a look at the steps involved:

1. Use Auth0 Rules to establish user roles and then add them to the ID (client user info) and access (API) tokens.
2. Implement middleware in our Node.js API to ensure only admin users can access certain API routes.
3. Use the role information in the Angular app to restrict access to certain routes and features.

Let's get started!

Use an Auth0 Rule for Admin Authorization

Rules are JavaScript functions that Auth0 executes each time a user authenticates. They provide an easy way to extend authentication functionality.

The first step is to log into your Auth0 dashboard and create a new Rule. Select the "Set roles to a user" rule template:

This opens up a JavaScript template. We only want to assign an admin role to our own account at this time. It'd be a good idea to change the name of this rule so we can see at a glance what it does. We can easily modify the template where it checks the user's email for indexOf() a specific email domain.

I'll change this to my full Google email address because that represents the identity that I want to assign the admin role to. I'll modify the rule to the following:

// Set me as 'admin' role, and all others to 'user'
// Save app_metadata to ID and access tokens
function (user, context, callback) {
  user.app_metadata = user.app_metadata || {};
  var addRolesToUser = function(user, cb) {
    if (user.email && user.email === '[MY_FULL_GOOGLE_ACCOUNT_EMAIL]') {
      cb(null, ['admin']);
    } else {
      cb(null, ['user']);
    }
  };

  addRolesToUser(user, function(err, roles) {
    if (err) {
      callback(err);
    } else {
      user.app_metadata.roles = roles;
      auth0.users.updateAppMetadata(user.user_id, user.app_metadata)
        .then(function(){
          // Add metadata to both ID token and access token
          var namespace = 'http://myapp.com/roles';
          var userRoles = user.app_metadata.roles;
          context.idToken[namespace] = userRoles;
          context.accessToken[namespace] = userRoles;
          callback(null, user, context);
        })
        .catch(function(err){
          callback(err);
        });
    }
  });
}

Replace [MY_FULL_GOOGLE_ACCOUNT_EMAIL] with your own credentials. We're replacing indexOf() with a strict equality expression === because we want to match a full email address rather than just a domain as in the example rule template.

Note: If you want to use a non-Google IdP account, make sure you identify the account by an appropriate property. Not all properties are returned by all connection types. You can also be more explicit regarding the details of the account if you want all accounts with that email to be set as administrators, or if you want only a Google account versus a username/password account to match the check. You can check your Auth0 Users or test your Auth0 Social Connections to see what kind of data is returned and stored from logins from different identity providers.

We added app_metadata with a roles array to our users, but since this isn't included in the OpenID standard claims, we need to add custom claims in order to include roles data in the ID and access tokens when the updateAppMetadata() promise is resolved.

The namespace identifier can be any non-Auth0 HTTP or HTTPS URL and does not have to point to an actual resource. Auth0 enforces this recommendation from OIDC regarding additional claims and will silently exclude any claims that do not have a namespace. You can read more about implementing custom claims with Auth0 here.

The key for our custom claim will be http://myapp.com/roles. This is how we'll retrieve the roles array from the ID and access tokens in our Angular app and Node API. Our rule assigns the Auth0 user's app_metadata.roles to this property.

When finished, click the "Save" button to save this rule.

Sign In with Admin Account

The next thing we need to do is sign in with our intended admin user. This will trigger the rule to execute and the app metadata will be added to our targeted account. Then the roles data will also be available in the tokens whenever the user logs in.

Since we've implemented login in our Angular app already, all we need to do is sign in with the account we specified in our Set roles to a user rule. Visit your Angular app in the browser at http://localhost:4200 and click the "Log In" link we added in the header.

Note: Recall that I used a Google account when setting up the Set roles to a user rule, so I'll log in using Google OAuth. (I enabled Google OAuth in Auth0 Dashboard Social Connections back in Auth0 Account and Setup in Part 1 of the tutorial series.)

Once you've logged in, you can check to verify that the appropriate role was added to your user account in the Auth0 Dashboard Users section. Find the user you just logged in with and click the name to view details. This user's Metadata section should now look like this:

Admin Middleware in Node API

Now that we have role support with our authentication, we can use this to protect API routes that require administrator access.

Open the server config.js file and add a NAMESPACE property with the namespace we used when creating our Add user role to tokens rule:

// server/config.js
module.exports = {
  ...,
  NAMESPACE: 'http://myapp.com/roles'
};

Note: If you modified the existing rule template in the Auth0 Rules dashboard and did not change the namespace to match the example code above, you should be mindful of this when setting up your configurations.

We can now implement middleware that will verify that a user is authenticated and has admin privileges to access API endpoints.

Make the following additions to the server api.js file:

// server/api.js
...
module.exports = function(app, config) {
  // Authentication middleware
  const jwtCheck = jwt({
    ...
  });

  // Check for an authenticated admin user
  const adminCheck = (req, res, next) => {
    const roles = req.user[config.NAMESPACE] || [];
    if (roles.indexOf('admin') > -1) {
      next();
    } else {
      res.status(401).send({message: 'Not authorized for admin access'});
    }
  }

...

Our Add user role to tokens rule added the following key/value pair to our ID and access tokens:

"http://myapp.com/roles": ["admin"]

The express-jwt package adds the decoded token to req.user by default. The adminCheck middleware finds this property and looks for a value of admin in the array. If found, the request proceeds. If not, a 401 Unauthorized status is returned with a short error message.

Now our API is set up to handle admin roles.

Admin Authorization in Angular App

We also want the front end to know if the user is an admin or not, so let's update our AuthService to get and store this information.

First, we need to store the namespace in our AUTH_CONFIG. Open the auth.config.ts file and add a NAMESPACE key:

// src/app/auth/auth.config.ts
...
interface AuthConfig {
  ...,
  NAMESPACE: string;
};

export const AUTH_CONFIG: AuthConfig = {
  ...,
  NAMESPACE: 'http://myapp.com/roles'
};

Now that we have the namespace stored, let's add support for storing admin status in the auth.service.ts file:

// src/app/auth/auth.service.ts
...
export class AuthService {
  ...
  isAdmin: boolean;

  ...

  private _setSession(authResult, profile) {
    ...
    // If initial login, set profile and admin information
    if (profile) {
      ...
      this.isAdmin = this._checkAdmin(profile);
    }
    // Update login status in loggedIn$ stream
    ...
  }

  private _checkAdmin(profile) {
    // Check if the user has admin role
    const roles = profile[AUTH_CONFIG.NAMESPACE] || [];
    return roles.indexOf('admin') > -1;
  }

  ...

First we'll add a new property called isAdmin: boolean. This will store the user's admin status so we can use it in the front end.

Next we'll update the _setSession() function. After setting the local userProfile property, we'll use a private _checkAdmin() method to determine whether the user has admin in their roles.

We now have the ability to check whether or not a user has admin privileges on the client side.

Security Note: This should never be done on the client-side alone. Always ensure that API routes are protected as well, as we've done in the API middleware section above.

We now have admin authorization set up on both our API and in our Angular app. We'll do a lot more with this as we develop our application!

Planning App Features

We have our database, Angular app, authentication, and secured Node API structurally ready for further development. Now it's time to do some feature planning and data modeling. It's vitally important to plan an application's data structure before diving straight into writing endpoints and business logic.

"It's vital to plan data structure before writing endpoints and business logic."

TWEET THIS

Let's consider our RSVP app's intended features at a high level, then we'll extrapolate what our database schema models should look like in order to bring these features to life.

Events

• Main listing of public events available on homepage with search feature; this should only show future events
• Full listing of all events (public, private, future, past) available for admins
• Detail view of event allows authenticated users to RSVP and to view who else has RSVPed
• Events can only be created, edited, and deleted by admins
• Deleting an event should also delete all RSVPs for that event
• Events can be listed publicly on the homepage, or excluded from the listing and accessed directly with a link
• Event RSVPs should be retrieved by event ID

Event Fields

• Event ID (automatically generated by MongoDB, also serves as direct link)
• Title of event
• Location
• Start date and time
• End date and time
• Description
• Public listing vs. requires a link to view

RSVPs

• Any authenticated user can RSVP for an event that is in the future, either via direct link or from the homepage listing
• Users cannot add or edit an RSVP for an event that has ended
• Users can update their own existing RSVP responses, but not delete them (RSVPs are deleted if the associated event is deleted)

RSVP Fields

• RSVP ID (automatically generated by MongoDB)
• User ID
• Name
• Event ID
• Attending / Not attending
• Number of additional (+1) guests (only applicable if attending)
• Comments

Users

• Users should be able to view a list of all their own RSVPs in their profile
• User data handled through Auth0 authentication and profile retrieval; users aren't stored in MongoDB
• Users are associated with their RSVPs by user ID
• In order to edit an RSVP, the user's ID must be verified with the user ID in the RSVP
• Admin users can perform CRUD operations on events

Data Modeling

We now have an idea about what features our events and RSVPs need to support. Let's create both the server and client-side models necessary to support our application.

Create Mongoose Schema

First we'll create the necessary schema to leverage our database. Create a new folder in the server directory called models. In this folder, add a file called Event.js and a file called Rsvp.js. These will contain our Event and Rsvp models. We're using mongoose for MongoDB object modeling. Each mongoose schema maps to a MongoDB collection and defines the shape of the documents within that collection.

We'll start with Event.js. Open this file and add the following event schema:

// server/models/Event.js
/*
 |--------------------------------------
 | Event Model
 |--------------------------------------
 */

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const eventSchema = new Schema({
  title: { type: String, required: true },
  location: { type: String, required: true },
  startDatetime: { type: Date, required: true },
  endDatetime: { type: Date, required: true },
  description: String,
  viewPublic: { type: Boolean, required: true }
});

module.exports = mongoose.model('Event', eventSchema);

This schema maps to our outlined features for events.

Note: We don't need to create an ID field because MongoDB object IDs will be generated automatically.

Now let's write the Rsvp schema in the Rsvp.js file:

// server/models/Rsvp.js
/*
 |--------------------------------------
 | Rsvp Model
 |--------------------------------------
 */

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const rsvpSchema = new Schema({
  userId: { type: String, required: true },
  name: { type: String, required: true },
  eventId: { type: String, required: true },
  attending: { type: Boolean, required: true },
  guests: Number,
  comments: String
});

module.exports = mongoose.model('Rsvp', rsvpSchema);

Now we need to require our models in the API. Open the server api.js file and add the following:

// server/api.js
/*
 |--------------------------------------
 | Dependencies
 |--------------------------------------
 */
...
const Event = require('./models/Event');
const Rsvp = require('./models/Rsvp');
...

We'll use these models to retrieve data from MongoDB in our endpoints, but first let's model the data on the front end as well.

Add Models to Angular App

We'll also add event and RSVP models in the front end to define the shape of the data we expect to retrieve when making API calls. Create two new class files with the CLI:

$ ng g class core/models/event.model
$ ng g class core/models/rsvp.model

Let's add the event model code in event.model.ts:

// src/app/core/models/event.model.ts
export class EventModel {
  constructor(
    public title: string,
    public location: string,
    public startDatetime: Date,
    public endDatetime: Date,
    public viewPublic: boolean,
    public description?: string,
    public _id?: string,
  ) { }
}

We're naming the models EventModel (and RsvpModel) to avoid conflicts with existing Event constructors if your editor or IDE uses intelligent code completion. Optional members must be listed after required members. The _id property is optional because it only exists if we're retrieving data from the database, but not if we're creating new records.

Now add the RSVP model in rsvp.model.ts:

// src/app/core/models/rsvp.model.ts
export class RsvpModel {
  constructor(
    public userId: string,
    public name: string,
    public eventId: string,
    public attending: boolean,
    public guests?: number,
    public comments?: string,
    public _id?: string
  ) { }
}

Create and Seed Collections in MongoDB

In order to query the database, we first need to create the necessary collections and provide a little bit of seed data. There are a couple of ways we could do this: either through mLab, or in MongoBooster (with the Mongo shell), which we set up earlier. Let's use MongoBooster because this method can be used with any MongoDB database, not just mLab.

Create Collections

Open your MongoBooster app to the mLab connection we created during our MongoDB Setup.

Once you've connected, right-click the database in the left sidebar and select "Create Collection...". When prompted, enter the collection name events. Click "Ok" and then create a second collection called rsvps. You should now have two empty collections listed in your database.

Add Event Seed Documents

Now we'll add some documents to the events collection for seed data. Right-click the collection name in the sidebar and select "Insert Documents...". The Mongo shell will open with db.events.insert([{}]) prompting you to add data. Replace this with the following:

db.events.insert([{
  "title": "Test Event Past",
  "location": "Home",
  "description": "This event took place in the past.",
  "startDatetime": ISODate("2018-05-04T18:00:00.000-04:00"),
  "endDatetime": ISODate("2018-05-04T20:00:00.000-04:00"),
  "viewPublic": true
}, {
  "title": "MongoBooster Test",
  "location": "Seattle, WA",
  "description": "I entered this seed event into the database using Mongo shell.",
  "startDatetime": ISODate("2019-08-12T20:00:00.000-04:00"),
  "endDatetime": ISODate("2019-08-13T10:00:00.000-04:00"),
  "viewPublic": true
}, {
  "title": "Bob's Private Event",
  "location": "Bob's House",
  "description": "An event at Bob's house.",
  "startDatetime": ISODate("2019-10-05T12:30:00.000-04:00"),
  "endDatetime": ISODate("2019-10-05T14:30:00.000-04:00"),
  "viewPublic": false
}])

Important Note: Make sure you update the seed data dates so that most of them are in the future and at least one is in the past. You may need to make changes depending on the current date versus the publication date of this tutorial. You'll also want at least one to have a viewPublic value of false.

When finished, click "Run" in the top bar. A console tab and a result tab should appear. You can then double-click on the events collection again to see your new documents listed. They should each have an _id property containing the automatically-generated object ID and should look something like this:

Add RSVP Seed Documents

Let's add a few documents to the rsvps collection as well. We'll assign the RSVPs to the seed events, so make sure you copy the object ID string (for the RSVP eventId) from a couple of event documents. You can do this by right-clicking an event document and selecting "View Document...". You can then copy the string from the "_id" : ObjectId(string) in the JSON Viewer.

We also need to assign RSVPs to user IDs. You can get specific user IDs by going to the Auth0 Dashboard Users and copying the user_id from the Identity Provider Attributes of whichever accounts you'd like to associate RSVPs to. Then when you log into the app with any of those accounts, the seed data RSVPs will be associated with the authentication service's userProfile.sub property.

Using this information, we can create some seed data for RSVPs. Let's add a couple of documents to the rsvps collection in our MongoDB database:

db.rsvps.insert([{
  "userId": "<IDP>|<USER_ID>",
  "eventId": "<EVENT_OBJECT_ID_STRING>",
  "attending": true,
  "guests": 3,
  "comments": "Really looking forward to this!"
}, {
  "userId": "<IDP>|<USER_ID>",
  "eventId": "<EVENT_OBJECT_ID_STRING>",
  "attending": false,
  "comments": "Regretfully, I can't make it."
}, {
  "userId": "<IDP>|<USER_ID>",
  "eventId": "<EVENT_OBJECT_ID_STRING>",
  "attending": true,
  "guests": 2
}])

Replace the information in angle brackets < > with user_ids from Auth0 and event IDs from the data we entered previously. This will set up the appropriate relationships.

The database should then look something like this in MongoBooster:

MongoBooster makes it simple to manipulate collections and documents as well as query the database with both the Mongo shell and a GUI. It's a handy tool to have at your disposal for any MongoDB project, and particularly useful if you need to work with a database that is not hosted on your local machine.

We now have some seed documents to work with so we can get our API and Angular app up and running with data available right off the bat.

Aside: Securing Applications with Auth0

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Summary

In Part 2 of our Real-World Angular Series, we've covered authentication and authorization, feature planning, and data modeling for our MEAN stack application. In the next part of the tutorial series, we'll tackle fetching data from the database with a Node API and displaying data with Angular, complete with filtering and sorting.