Instructions

Overview

• Prisma Setup
• Start NestJS Server
• Update Schema
• Deploy to Heroku
• Graphql Client

Prisma Setup

1. Install Prisma

Setup Prisma CLI

npm install -g prisma

2. Install Docker

Install Docker and start Prisma and the connected database by running the following command:

docker-compose up -d

3. Deploy Prisma

To deploy the Prisma schema run:

prisma deploy

Playground of Prisma is available here: http://localhost:4466/

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Start NestJS Server

To start the NestJS Server run:

npm run start

Playground for the NestJS Server is available here: http://localhost:3000/graphql

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Update Schema

Prisma - Database Schema

Update the Prisma schema prisma/datamodel.prisma and after that run the following two commands:

prisma deploy

prisma deploy will update the database and for each deploy prisma generate is executed. This will generate the latest Prisma Client to access Prisma from your resolvers.

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NestJS - Api Schema

Api Schema

Add or update the *.graphql schema with Queries or Mutations.

For example:

# Add user Query to user.graphql
type Query {
  ...
  user(id: ID): User
  ...
}

After starting NestJS this Query is available in the Playground, but will fail at the moment. This will be fixed in the next step. Add a new resolver function.

Resolver

To implement the new query, a new resolver function needs to be added to users.resolver.ts.

@Query('user')
async getUser(@Args() args): Promise<User> {
  return await this.prisma.client.user(args);
}

Restart the NestJS server and this time the Query to fetch a user should work.

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Deploy to Heroku

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Graphql Client

A graphql client is necessary to consume the graphql api provided by the NestJS Server.

Checkout Apollo a popular graphql client which offers several clients for React, Angular, Vue.js, Native iOS, Native Android and more.

Angular

Setup

To start using Apollo Angular simply run in an Angular and Ionic project:

ng add apollo-angular

HttpLink from apollo-angular requires the HttpClient. Therefore, you need to add the HttpClientModule to the AppModule:

imports: [BrowserModule,
    HttpClientModule,
    ...,
    GraphQLModule],

You can also add the GraphQLModule in the AppModule to make Apollo available in your Angular App.

You need to set the URL to the NestJS Graphql Api. Open the file src/app/graphql.module.ts and update uri:

const uri = 'http://localhost:3000/graphql';

To use Apollo-Angular you can inject private apollo: Apollo into the constructor of a page, component or service.

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Queries

To execute a query you can use:

this.apollo.query({query: YOUR_QUERY});

# or

this.apollo.watchQuery({
  query: YOUR_QUERY
}).valueChanges;

Here is an example how to fetch your profile from the NestJS Graphql Api:

const CurrentUserProfile = gql`
  query CurrentUserProfile {
    me {
      id
      email
      name
    }
}`;


@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage implements OnInit {

  data: Observable<any>;

  constructor(private apollo: Apollo) { }

  ngOnInit() {
    this.data = this.apollo.watchQuery({
      query: CurrentUserProfile
    }).valueChanges;
  } 
}

Use the AsyncPipe and SelectPipe to unwrap the data Observable in the template:

<div *ngIf="data | async | select: 'me' as me">
    <p>Me id: {{me.id}}</p>
    <p>Me email: {{me.email}}</p>
    <p>Me name: {{me.name}}</p>
</div>

Or unwrap the data using RxJs.

This will end up in an GraphQL error because Me is protected by an @UseGuards(GqlAuthGuard) and requires an Bearer TOKEN. Please refer to the Authentication section.

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Mutations

To execute a mutation you can use:

this.apollo.mutate({
  mutation: YOUR_MUTATION
});

Here is an example how to login into your profile using the login Mutation:

const Login = gql`
  mutation Login {
  login(email: "[email protected]", password: "pizzaHawaii") {
    token
    user {
      id
      email
      name
    }
  }
}`;

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage implements OnInit {

  data: Observable<any>;

  constructor(private apollo: Apollo) { }

  ngOnInit() {
    this.data = this.apollo.mutate({
      mutation: Login
    });
  }

}

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Subscriptions

To execute a subscription you can use:

this.apollo.subscribe({
  query: YOUR_SUBSCRIPTION_QUERY
})

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Authentication

To authenticate your requests you have to add your TOKEN you receive on signup and login mutation to each request which is protected by the @UseGuards(GqlAuthGuard).

Because the apollo client is using HttpClient under the hood you are able to simply use an Interceptor to add your token to the requests.

Create the following class:

import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class TokenInterceptor implements HttpInterceptor {

    constructor() { }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        const token = 'YOUR_TOKEN'; // get from local storage
        if (token !== undefined) {
            req = req.clone({
                setHeaders: {
                    Authorization: `Bearer ${token}`
                }
            });
        }

        return next.handle(req);
    }
}

Add the Interceptor to the AppModule providers like this:

providers: [
    ...
    { provide: HTTP_INTERCEPTORS, useClass: TokenInterceptor, multi: true },
    ...
  ]

After you configured the Interceptor and retrieved the TOKEN from storage your request will succeed on resolvers with @UseGuards(GqlAuthGuard).

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