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GraphQL

With Apollo

Using pg_grapqhl with Apollo.

This guide will show you how to use pg_graphql with Apollo and GraphQL Code Generator for type-safe GraphQL queries in your React application.

Apollo Setup

Pre-requisites

  1. Follow the Apollo Getting Started Guide.
  2. Follow the GraphQL Code Generator Installation Guide.

Configuring GraphQL Code Generator

Modify your codegen.ts file to reflect the following:


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import type { CodegenConfig } from '@graphql-codegen/cli'
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import { addTypenameSelectionDocumentTransform } from '@graphql-codegen/client-preset'
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const config: CodegenConfig = {
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schema: 'http://localhost:54321/graphql/v1', // Using the local endpoint, update if needed
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documents: 'src/**/*.tsx',
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overwrite: true,
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ignoreNoDocuments: true,
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generates: {
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'src/gql/': {
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preset: 'client',
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documentTransforms: [addTypenameSelectionDocumentTransform],
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plugins: [],
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config: {
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scalars: {
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UUID: 'string',
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Date: 'string',
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Time: 'string',
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Datetime: 'string',
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JSON: 'string',
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BigInt: 'string',
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BigFloat: 'string',
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Opaque: 'any',
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},
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},
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},
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},
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hooks: {
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afterAllFileWrite: ['npm run prettier'], // optional
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},
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}
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export default config

Configuring Apollo Client

This example uses Supabase for the GraphQL server, but pg_graphql can be used independently.


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import {
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ApolloClient,
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InMemoryCache,
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createHttpLink,
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defaultDataIdFromObject
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} from '@apollo/client'
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import { setContext } from '@apollo/client/link/context'
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import { relayStylePagination } from '@apollo/client/utilities'
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import supabase from './supabase'
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const cache = new InMemoryCache({
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dataIdFromObject(responseObject) {
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if ('nodeId' in responseObject) {
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return `${responseObject.nodeId}`
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}
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return defaultDataIdFromObject(responseObject)
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},
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possibleTypes: { Node: ['Todos'] } // optional, but useful to specify supertype-subtype relationships
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typePolicies: {
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Query: {
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fields: {
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todosCollection: relayStylePagination(), // example of paginating a collection
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node: {
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read(_, { args, toReference }) {
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const ref = toReference({
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nodeId: args?.nodeId,
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})
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return ref
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},
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},
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},
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},
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},
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})
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const httpLink = createHttpLink({
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uri: 'http://localhost:54321/graphql/v1',
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})
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const authLink = setContext(async (_, { headers }) => {
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const token = (await supabase.auth.getSession()).data.session?.access_token
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return {
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headers: {
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...headers,
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Authorization: token ? `Bearer ${token}` : '',
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},
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}
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})
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const apolloClient = new ApolloClient({
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link: authLink.concat(httpLink),
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cache,
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})
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export default apolloClient

  • typePolicies.Query.fields.node is also optional, but useful for reducing cache misses. Learn more about Redirecting to cached data.

Example Query


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import { useQuery } from '@apollo/client'
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import { graphql } from './gql'
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const allTodosQueryDocument = graphql(/* GraphQL */ `
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query AllTodos($cursor: Cursor) {
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todosCollection(first: 10, after: $cursor) {
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edges {
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node {
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nodeId
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title
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}
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}
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pageInfo {
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endCursor
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hasNextPage
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}
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}
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}
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`)
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const TodoList = () => {
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const { data, fetchMore } = useQuery(allTodosQueryDocument)
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return (
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<>
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{data?.thingsCollection?.edges.map(({ node }) => (
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<Todo key={node.nodeId} title={node.title} />
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))}
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{data?.thingsCollection?.pageInfo.hasNextPage && (
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<Button
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onClick={() => {
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fetchMore({
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variables: {
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cursor: data?.thingsCollection?.pageInfo.endCursor,
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},
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})
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}}
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>
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Load More
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</Button>
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)}
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</>
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)
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}
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export default TodoList