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Wrap a REST API endpoint with GraphQL in Node.js

Follow this tutorial to wrap a REST API endpoint with a GraphQL wrapper to make it accessible via a dedicated GraphQL API.

In this tutorial we will use a standalone Apollo server, which is an easy-to-use option for setting up a GraphQL server without any additional configuration. For the REST API endpoint we will use the City Search API.

The goal of this tutorial is to create a GraphQL API, which will only use the keyword parameter for the query and return only the name parameter in the response.

Pre-requisites

Before you begin, you need to:

  • Register your application with Amadeus for Developers as described in Making your first API call.
  • Have Node.js installed on your machine.

Initialize a new Node.js project

  1. Open your terminal and create a new directory for this project: 
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    mkdir graphql-wrapper
  2. Navigate to the directory and run the following command to initialize a new Node.js project: 
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    cd graphql-wrapper
npm init -y

Install required dependencies

Install apollo-server, graphql, and node-fetch packages by running:

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npm install apollo-server graphql node-fetch

Define GraphQL schema

Create a schema.graphql file with the necessary types and queries. In this tutorial, we are only using the keyword parameter to query the City Search API and we are only interested in the name parameters that this query returns in the response data. For this reason, our schema.graphql will look as follows:

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type Query {
  getCities(keyword: String!): [City]
}

type City {
  name: String
}

Create a data fetching function

Information

The node-fetch package is an ECMAScript module (ESM), so we will use .mjs extensions and ECMAScript module syntax in these examples.

Create a fetchData.mjs file and define a function that fetches data from the REST endpoint using node-fetch:

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import fetch from 'node-fetch';


const fetchCities = async (keyword, token) => {
  const endpoint = `https://test.api.amadeus.com/v1/reference-data/locations/cities?keyword=${keyword}`;

  const response = await fetch(endpoint, {
    headers: {
      'Authorization': `Bearer ${token}`
    }
  });

  const data = await response.json();

  console.log('API Response:', data);

  return data.data;
};

export { fetchCities };

In the above example we are outputting logs to the console for easier troubleshooting.

Implement GraphQL resolvers

Create a resolvers.mjs file and implement the resolver functions for the queries:

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import { fetchCities } from './fetchData.mjs';

const resolvers = {
  Query: {
    getCities: async (_, { keyword }, { token }) => {
      const cities = await fetchCities(keyword, token);
      return cities.map(city => ({ name: city.name }));
    },
  },
};

export default resolvers;

Set up the Apollo server

Create the main file index.mjs that sets up the Apollo server with the schema and resolvers:

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import { ApolloServer, gql } from 'apollo-server';
import { readFileSync } from 'fs';
import resolvers from './resolvers.mjs';

const typeDefs = gql(readFileSync('./schema.graphql', 'utf8'));

const server = new ApolloServer({
  typeDefs,
  resolvers,
  context: ({ req }) => {
    const token = req.headers.authorization || '';

    return { token };
  },
});

server.listen().then(({ url }) => {
  console.log(`🚀 Server ready at ${url}`);
});

Run the server

Open the terminal and run:

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node index.mjs

Query the GraphQL API

Information

Before running the query, make sure to obtain the token as described in our Authorization guide.

Now that we have the server running, we can send requests to it. The most straightforward method to do this is by using curl. To query this API by the keyword "Paris":

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curl -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: <your_bearer_token>" \
  -d '{ "query": "{ getCities(keyword: \"PARIS\") { name } }" }' \
  http://localhost:4000/

If your token is valid, the above command will return a list of city names that contain the word Paris.

Last update: October 31, 2023