In the previous article Setting up GraphQL API with MongoDB and Apollo Server for a NextJS app we've created a GraphQL API with Apollo Server setup and connection to the MongoDB. We worked mainly on the server side of the application.
It's recommended to read and follow along the first part if you haven't.
In this article, we're moving to the client side of the application and we'll learn how to consume an API that we've created in the first part. Meaning, performing queries from our NextJS application to the GraphQL API.
An idea
In order to perform queries to our GraphQL API from the client-side (and not only from the GraphQL Playground) we'll need to setup Apollo Client.
Using a custom implementation of the withApollo() high-order component we are going to wrap index file with it and make queries to the API.
Installing Apollo Client and related dependencies
yarn add apollo-client @apollo/react-hooks @apollo/react-ssr apollo-cache-inmemory apollo-link-http apollo-link-schema graphql-tag
Setting up an Apollo Client
At the project root let's create a folder called apollo/ with a client.js file inside.
// apollo/client.js
import React from 'react'
import Head from 'next/head'
import { ApolloProvider } from '@apollo/react-hooks'
import { ApolloClient } from 'apollo-client'
import { InMemoryCache } from 'apollo-cache-inmemory'
let globalApolloClient = null
/**
* Creates and provides the apolloContext
* to a next.js PageTree. Use it by wrapping
* your PageComponent via HOC pattern.
* @param {Function|Class} PageComponent
* @param {Object} [config]
* @param {Boolean} [config.ssr=true]
*/
export function withApollo(PageComponent, { ssr = true } = {}) {
const WithApollo = ({ apolloClient, apolloState, ...pageProps }) => {
const client = apolloClient || initApolloClient(apolloState)
return (
<ApolloProvider client={client}>
<PageComponent {...pageProps} />
</ApolloProvider>
)
}
// Set the correct displayName in development
if (process.env.NODE_ENV !== 'production') {
const displayName =
PageComponent.displayName || PageComponent.name || 'Component'
if (displayName === 'App') {
console.warn('This withApollo HOC only works with PageComponents.')
}
WithApollo.displayName = `withApollo(${displayName})`
}
if (ssr || PageComponent.getInitialProps) {
WithApollo.getInitialProps = async (ctx) => {
const { AppTree } = ctx
// Initialize ApolloClient, add it to the ctx object so
// we can use it in `PageComponent.getInitialProp`.
const apolloClient = (ctx.apolloClient = initApolloClient())
// Run wrapped getInitialProps methods
let pageProps = {}
if (PageComponent.getInitialProps) {
pageProps = await PageComponent.getInitialProps(ctx)
}
// Only on the server:
if (typeof window === 'undefined') {
// When redirecting, the response is finished.
// No point in continuing to render
if (ctx.res && ctx.res.finished) {
return pageProps
}
// Only if ssr is enabled
if (ssr) {
try {
// Run all GraphQL queries
const { getDataFromTree } = await import('@apollo/react-ssr')
await getDataFromTree(
<AppTree
pageProps={{
...pageProps,
apolloClient,
}}
/>
)
} catch (error) {
// Prevent Apollo Client GraphQL errors from crashing SSR.
// Handle them in components via the data.error prop:
// https://www.apollographql.com/docs/react/api/react-apollo.html#graphql-query-data-error
console.error('Error while running `getDataFromTree`', error)
}
// getDataFromTree does not call componentWillUnmount
// head side effect therefore need to be cleared manually
Head.rewind()
}
}
// Extract query data from the Apollo store
const apolloState = apolloClient.cache.extract()
return {
...pageProps,
apolloState,
}
}
}
return WithApollo
}
/**
* Always creates a new apollo client on the server
* Creates or reuses apollo client in the browser.
* @param {Object} initialState
*/
function initApolloClient(initialState) {
// Make sure to create a new client for every server-side request so that data
// isn't shared between connections (which would be bad)
if (typeof window === 'undefined') {
return createApolloClient(initialState)
}
// Reuse client on the client-side
if (!globalApolloClient) {
globalApolloClient = createApolloClient(initialState)
}
return globalApolloClient
}
/**
* Creates and configures the ApolloClient
* @param {Object} [initialState={}]
*/
function createApolloClient(initialState = {}) {
const ssrMode = typeof window === 'undefined'
const cache = new InMemoryCache().restore(initialState)
// Check out https://github.com/vercel/next.js/pull/4611 if you want to use the AWSAppSyncClient
return new ApolloClient({
ssrMode,
link: createIsomorphLink(),
cache,
})
}
function createIsomorphLink() {
if (typeof window === 'undefined') {
const { SchemaLink } = require('apollo-link-schema')
const { schema } = require('./schema')
return new SchemaLink({ schema })
} else {
const { HttpLink } = require('apollo-link-http')
return new HttpLink({
uri: '/api/graphql',
credentials: 'same-origin',
})
}
}
Sharing schema for Apollo Client and Server
Our GraphQL schema is located now under the pages/api/graphql.js alongside with our Apollo Server setup.
Before we had all the setup in on file on the server, like so:
import { ApolloServer, gql } from 'apollo-server-micro'
import { makeExecutableSchema } from 'graphql-tools'
import { MongoClient } from 'mongodb'
require('dotenv').config()
const typeDefs = gql`
type User {
id: ID!
firstName: String!
lastName: String!
blog: String
stars: Int
}
type Query {
users: [User]!
}
`
const resolvers = {
Query: {
users(_parent, _args, _context, _info) {
return _context.db
.collection('users')
.findOne()
.then((data) => {
return data.users
})
},
},
}
const schema = makeExecutableSchema({
typeDefs,
resolvers,
})
let db
const apolloServer = new ApolloServer({
schema,
context: async () => {
if (!db) {
try {
const dbClient = new MongoClient(process.env.MONGO_DB_URI, {
useNewUrlParser: true,
useUnifiedTopology: true,
})
if (!dbClient.isConnected()) await dbClient.connect()
db = dbClient.db('next-graphql')
} catch (e) {
console.log('--->error while connecting with graphql context (db)', e)
}
}
return { db }
},
})
export const config = {
api: {
bodyParser: false,
},
}
export default apolloServer.createHandler({ path: '/api/graphql' })
However we need to access schema on the client side as well so let's move typeDefs, resolvers and schema setup to the apollo folder on the client and just import it on the server.
Inside the apollo/ folder let's create type-defs.js, resolvers.js and schema.js files and move respective parts in there so you would have a file structure like this:
// apollo/type-defs.js
import gql from 'graphql-tag'
export const typeDefs = gql`
type User {
id: ID!
firstName: String!
lastName: String!
blog: String
stars: Int
}
type Query {
users: [User]!
}
`
// apollo/revolvers.js
export const resolvers = {
Query: {
users(_parent, _args, _context, _info) {
return _context.db
.collection('users')
.findOne()
.then((data) => {
return data.users
})
},
},
}
// apollo/schema.js
import { makeExecutableSchema } from 'graphql-tools'
import { typeDefs } from './type-defs'
import { resolvers } from './resolvers'
export const schema = makeExecutableSchema({
typeDefs,
resolvers,
})
After moving files to the client our Apollo Server setup looks nice and clean:
// pages/api/graphql.js
import { ApolloServer } from 'apollo-server-micro'
import { MongoClient } from 'mongodb'
import { schema } from '../../apollo/schema'
require('dotenv').config()
let db
const apolloServer = new ApolloServer({
schema,
context: async () => {
if (!db) {
try {
const dbClient = new MongoClient(process.env.MONGO_DB_URI, {
useNewUrlParser: true,
useUnifiedTopology: true,
})
if (!dbClient.isConnected()) await dbClient.connect()
db = dbClient.db('next-graphql')
} catch (e) {
console.log('--->error while connecting with graphql context (db)', e)
}
}
return { db }
},
})
export const config = {
api: {
bodyParser: false,
},
}
export default apolloServer.createHandler({ path: '/api/graphql' })
After the refactoring our API still works as expected:
Create Users component and perform queries to the GraphQL API
Create components/Users.js component which will display a list of users:
// components/Users.js
import React from 'react'
import gql from 'graphql-tag'
import { useQuery } from '@apollo/react-hooks'
const UsersQuery = gql`
query Users {
users {
id
firstName
}
}
`
const Users = () => {
const { loading, error, data } = useQuery(UsersQuery)
if (loading) return 'loading users...'
if (error) return 'error while loading users'
return (
<div>
<table>
<thead>
<tr>
<th>First Name</th>
</tr>
</thead>
<tbody>
{data.users.map((user) => (
<tr key={user.id}>
<td>{user.firstName}</td>
</tr>
))}
</tbody>
</table>
</div>
)
}
export default Users
Wrap Index file withApollo() HOC
In order for GraphQL Queries to work we need to wrap our Index page withApollo() HOC.
Let's refactor our Index page to display the Users component and import withApollo().
// pages/index.js
import Head from 'next/head'
import Users from '../components/Users'
import { withApollo } from '../apollo/client'
const Index = () => {
return (
<div className="container">
<Head>
<title>Create Next App</title>
<link rel="icon" href="/favicon.ico" />
</Head>
<main>
<Users />
</main>
<footer>
<a
href="https://vercel.com?utm_source=create-next-app&utm_medium=default-template&utm_campaign=create-next-app"
target="_blank"
rel="noopener noreferrer"
>
Powered by{' '}
<img src="/vercel.svg" alt="Vercel Logo" className="logo" />
</a>
</footer>
<style jsx>{`
.container {
min-height: 100vh;
padding: 0 0.5rem;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
main {
padding: 5rem 0;
flex: 1;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
footer {
width: 100%;
height: 100px;
border-top: 1px solid #eaeaea;
display: flex;
justify-content: center;
align-items: center;
}
footer img {
margin-left: 0.5rem;
}
footer a {
display: flex;
justify-content: center;
align-items: center;
}
a {
color: inherit;
text-decoration: none;
}
.description {
line-height: 1.5;
font-size: 1.5rem;
}
.logo {
height: 1em;
}
`}</style>
<style jsx global>{`
html,
body {
padding: 0;
margin: 0;
font-family: -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Oxygen,
Ubuntu, Cantarell, Fira Sans, Droid Sans, Helvetica Neue, sans-serif;
}
* {
box-sizing: border-box;
}
`}</style>
</div>
)
}
export default withApollo(Index)
That's it! We can perform queries to our GraphQL API with Apollo Client and fetch data from the MongoDB.
graphql-apollo-mongodb-example
I created a supporting repository for this article so you can follow along commit-by-commit.
See deployed project preview here.
Originally posted on oleks.pro
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