Implementing our RESTDataSource

4. Implementing our RESTDataSource

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Let's add this RESTDataSource class to our project.

In the terminal, in our server/ folder, stop the current process that we started in the project setup section, then run:

npm install apollo-datasource-rest

Once that's done, start up the server again with npm start.

Next, let's create a folder called datasources in the server/src folder, where all our data sources will live. We'll create a file called track-api.js.

First, we import our apollo-datasource-rest package.

const { RESTDataSource } = require("apollo-datasource-rest");

This gives us a RESTDataSource class that we can extend.

We'll declare a class called TrackAPI that extends RESTDataSource. While we're here, let's export it before we forget!

class TrackAPI extends RESTDataSource {
  // ...
}
module.exports = TrackAPI;

Let's define a constructor method inside the class. Inside, we'll call super() to make sure we get access to our RESTDataSource features. We'll also assign our REST API's base url.

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class TrackAPI extends RESTDataSource {
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  constructor() {
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    super();
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    this.baseURL = "https://odyssey-lift-off-rest-api.herokuapp.com/";
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  }
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}

Code Challenge!

Create a class called SpaceCatsAPI that extends the RESTDataSource class. It should have a constructor method. Its baseURL should be set to https://fake-spacecats-rest-api.cat/. Assume that the RESTDataSource class has already been imported.

Let's define a method called getTracksForHome inside our TrackAPI class. The RESTDataSource class provides helper methods for HTTP requests. In our case, we want to perform a GET request to the tracks endpoint. Then, we return the results of that call.

Below our constructor method:

getTracksForHome() {
  return this.get('tracks');
}

Next, it's time to define the getAuthor method inside our TrackAPI class. It takes an authorId as an argument and uses it in a GET call to the /author/:id endpoint. Then, we return the results of that call.

Below our getTracksForHome method:

getAuthor(authorId) {
  return this.get(`author/${authorId}`);
}

Note the use of backticks (`) enclosing the author/:id endpoint, because we're using string interpolation to add the authorId at the end.

Nice work! We've got our data source set up and retrieving data from the REST API.

server/src/datasources/track-api.js

const { RESTDataSource } = require("apollo-datasource-rest");

class TrackAPI extends RESTDataSource {
  constructor() {
    super();
    this.baseURL = "https://odyssey-lift-off-rest-api.herokuapp.com/";
  }

  getTracksForHome() {
    return this.get("tracks");
  }

  getAuthor(authorId) {
    return this.get(`author/${authorId}`);
  }
}

module.exports = TrackAPI;

Code Challenge!

The SpaceCatsAPI class needs two methods. The first method is called getSpaceCats. This method makes a GET request to the spacecats endpoint and returns the results. The second method is called getMissions. It takes in a catId as an argument and makes a GET request to the spacecats/${catId}/missions endpoint and returns the results. Assume that the RESTDataSource class has already been imported.

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