Monday, 20 May, 2019 UTC

Fullstack GraphQL Beginner Tutorial - Instagram Clone

Fullstack GraphQL Beginner Tutorial - Instagram Clone

Summary

In this tutorial, we’ll build a simple Instagram clone using React and GraphQL. In our version, it will only contain cat pictures.
GraphQL allows you to fetch data using Queries and update it using Mutations. Today we’ll focus on fetching data. We’ll create both backend and frontend.
We’ll get a list of images with comments and display them as a feed.
Here’s how it will look:
Why Use GraphQL
Over the years, REST has become the standard for designing web APIs. It offers some great ideas, such as stateless servers and structured access to resources.
But designing a good REST API is a challenging task. It requires a good understanding of both REST architectural style and solid knowledge of HTTP protocol.
One of the usual problems with REST APIs is inefficient fetching.
For example, it can be under-fetching. When you don’t have enough data from one endpoint and it requires you to do multiple round-trips to collect everything that is needed
Let’s consider a blog example. It has posts and each post can have multiple comments.
In REST API, one has to gather the required information from multiple endpoints. In order to fetch the content of a blog post and its comments, a client would have to first fetch a particular post and then request another endpoint for comments based on post id for every post.
Here we first get the post with id 1 to get its title (and maybe other fields, like content).
GET someblog.com/posts/1; // Which will return { id: 1, title: "Hello, it's my first post"; //... maybe other fields }
Now to get comments we make another call to our API:
GET someblog.com/posts/1/comments; // Which will return [ { id: 1, text: "Great post!" }, { id: 2, text: "First one!" } ]
In GraphQL, this can be achieved with a single instance query.
GET /graphql?query={ post(id: "1") { title, comments { text } } } { "title": "Hello, it's my first post", "comments": [ { text: "Great post!" }, { text: "First one!" } ] }
Using GraphQL it’s way easier to design a good API. It requires less thinking upfront and allows you to work on your queries and optimize them as you go.
Now let’s get back to our Kittengram example, and we’ll start with backend.
Making Backend
There are a bunch of Javascript libraries to write your GraphQL backend.
Among them GraphQL.js, express-graphql and apollo-server.
We’ll use apollo-server to build our GraphQL backend.

Step 1: Initialize project

In this step, we’ll use your terminal create a directory kittengram-server and initialize simple Node.js app there.
  • First, create a folder kittengram-server using the mkdir command.
    mkdir kittengram-server
  • Enter the directory.
    cd kittengram-server
  • Initialize new Node.js project using npm.
    npm init --yes
If everything is fine you should see the package.json file in your directory.

Step 2: Install dependencies

Next, we’ll install two dependencies which are necessary for responding to GraphQL requests:
  • apollo-server: The Apollo server library. Does all the heavy lifting. Allows us to focus on defining the shape of our data.
  • graphql: The library used to build a schema and to execute queries on that schema.
Run the following command to install both of these dependencies and save them in the project:
npm i --save apollo-server graphql

Step 3: Create the server

  • Open the kittengram-server directory using your IDE/editor.
  • Create a new file called index.js in the root of the project directory.
  • “Copy” and “Paste” the following code into the index.js file:
    const { ApolloServer, gql } = require("apollo-server"); const photos = [ { author: "🐈 Nala", url: "https://cataas.com/cat/cute/says/Apollo%20is%20awesome?size=50&color=magenta", comments: [ { author: "Coco", text: "Meow meow" }, { author: "Gracie", text: "Meow meow meow" } ] }, { author: "🐱 Loki", url: "https://cataas.com/cat/cute/says/GraphQL%20is%20awesome?size=50&color=magenta", comments: [ { author: "Jasper", text: "Meow" }, { author: "Oreo", text: "Meow meow" }, { author: "Tiger", text: "Meow" } ] } ]; const typeDefs = gql` type Comment { author: String text: String } type Photo { author: String url: String comments: [Comment] } type Query { photos: [Photo] } `; const resolvers = { Query: { photos: () => photos } }; const server = new ApolloServer({ typeDefs, resolvers }); server.listen().then(({ url }) => { console.log(`🐱 Server ready at ${url}`); });

Step 4: Start the server

Our application is ready to start.
  • Run the index.js file we created in the previous step using Node.js
    node index.js
    You should see the following output:
    🐱 Server ready at http://localhost:4000/
  • Open the address provided in your web browser.
    If everything is working, you should see the GraphQL Playground explorer tool, similar to one below
    The GraphQL Playground below is interactive so you can use it to play around

Step 5: Run your first query

At this point, you’ll be able to start sending queries to the GraphQL server using GraphQL Playground, which is split into two parts:
  • The request (on the left)
  • The response (on the right)
There is also a play button in the middle that makes it look like a video player, but it’s used to perform requests.
Enter the following query on the left side of the window, and press that Play button.
{ photos { url author comments { author text } } }
This query asks for a list of posts, including the url, author and list of comments for each post.
Now it’s time to work on the frontend.
Making Frontend
There are several libraries available to work with GraphQL on a client. Most popular of them are Relay and Apollo.
We’ll use Apollo with apollo-boost to simplify the setup.

Step 1: Application setup

In this tutorial, we’ll set up our application using create-react-app.
  • Create kittengram-client application.
    npx create-react-app kittengram-client
    Here I’ve used npx command to run create-react-app. You can run create-react-app directly if you have it installed locally.
    npx is an npm package runner. It is available with NodeJS installation since version 6.0. It’s often being used to run one-time commands without installing them first. But it can be used for other tasks too, read more about it here

Step 2: Install dependencies

As I’ve mentioned earlier we’ll use apollo-boost in this project. We’ll also use react-apollo to integrate GraphQL with React and graphql to parse queries.
Let’s install these packages.
npx i --save apollo-boost react-apollo graphql

Step 3: Create client

After we have all the dependencies installed - we need to initialize GraphQL client. The only argument it requires is the endpoint of your GraphQL server we’ve set up earlier (in our case http://localhost:4000).
  • Open your index.js file, import ApolloClient from apollo-boost and initialize the new client passing http://localhost:4000 as url property.
    import ApolloClient from "apollo-boost"; const client = new ApolloClient({ uri: "https://localhost:4000" });
  • You can verify that client is set up properly by sending a test query.
    import { gql } from "apollo-boost"; client .query({ query: gql` { photos { url author comments { author text } } ` }) .then(result => console.log(result));

Step 4: Integrate React

To connect Apollo Client to React, we’ll use the ApolloProvider. It works just like React Context provider, you can read more about React Context API here
  • In index.js, wrap your App with an ApolloProvider.
    import { ApolloProvider } from "react-apollo"; render( <ApolloProvider client={client}> <App /> </ApolloProvider>, document.getElementById("root") );

Step 5: Request data

Now you’re ready to start requesting data with Query components!
Query component uses the render prop pattern to share GraphQL data with your UI.
  • Add the following code to your App.js file.
    import React from "react"; import { Query } from "react-apollo"; import { gql } from "apollo-boost"; import "./App.css"; const App = () => ( <Query query={gql` { photos { url author comments { author text } } } `} > {({ loading, error, data }) => { if (loading) return <p>Loading...</p>; if (error) return <p>Error :(</p>; return data.photos.map(photo => ( <div key={photo.url}> {photo.author} <img src={photo.url} alt={photo.author} /> {photo.comments.map(comment => ( <div> {comment.author}: {comment.text} </div> ))} </div> )); }} </Query> ); export default App;
    Here we pass a GraphQL query parsed by gql to Query component as query prop.
    Then we pass a function as children to Query component. This function expects to get loading state, error if it exists and data as props.
    We use destructuring assignment to get specific prop fields.
    And finally we map through photos to display cat images, and comments.
You should see something like this:

Step 6: Styling it up

In my example, I’ve used styled-components to add styles to my application. You can find the code for them in this repo
Conclusion
At this point, you should have functioning backend and frontend for a simple React GraphQL application. In this example, we used only Queries to fetch the data.
  • Frontend code
  • Backend code
In one of the next tutorials, we’ll take a look at Mutations as a way to update data on the backend.

... more @ maksimivanov.com

maksimivanov.com