hops-react-apollo

Please see the main Hops Readme for general information and a Getting Started Guide.

This is a preset for Hops that can be used to set up an <ApolloProvider /> and enable client-side support for GraphQL via the Apollo framework.

Installation

This preset must be used together with the hops-react preset.

Add this preset and its peer dependencies to your existing Hops React project:

npm install --save hops-react-apollo react @apollo/client react-dom react-helmet-async react-router-dom

If you don't already have an existing Hops project read this section on how to set up your first Hops project.

CLI

graphql introspect

This command extracts the polymorphic relationships between interfaces and types that implement it and writes it to the location of fragmentsFile.

This is recommended if you have a more complex schema and are querying fragments on unions or interfaces.

Head over to https://www.apollographql.com/docs/react/data/fragments/ to read more details about this.

Arguments

-H / --header

Pass additional HTTP headers that should be sent when executing the introspection query against a remote GraphQL server. For example when your server requires an authentication token or similar.

This argument can be specified multiple times to add multiple HTTP headers.

Usage

Querying data on the client-side

In order to start using GraphQL in your application install this preset and configure the required options (see below).

Check out this integration test as an example for how to use this preset.

GraphQL in a Typescript project

If you're importing queries from .graphql/.gql-files as modules, you have to make these module types known to the TS compiler. Therefore add them to the assets.d.ts, that you should have in your project.

declare module '*.graphql';
declare module '*.gql';

Configuration

Preset Options

| Name | Type | Default | Required | Description | | --- | --- | --- | --- | --- | | fragmentsFile | String | <rootDir>/fragmentTypes.json | no | Where to store the generated fragment types file | | graphqlUri | String | '' | yes | Url to your GraphQL endpoint or mock server | | graphqlSchemaFile | String | '' | no | Path to your GraphQL schema file | | allowServerSideDataFetching | Boolean | true | no | Whether Hops is allowed to execute GraphQL queries during server-side rendering |

fragmentsFile

This option controls where the fragment type information that are used for the possibleTypes option should be saved.

By default executing $ hops graphql introspect will create a file called fragmentTypes.json in the application root directory.

"hops": {
  "fragmentsFile": "<rootDir>/fragmentTypes.json"
}

graphqlUri

This is the full URI to your GraphQL endpoint which should be used by the client- and server-side when executing requests.

This will also be used to generate fragment type information with $ hops graphql introspect in case no graphqlSchemaFile has been provided.

"hops": {
  "graphqlUri": "https://www.graphqlhub.com/graphql"
}

graphqlSchemaFile

In case your GraphQL server (configured via graphqlUri) does not answer to introspection queries, you can provide the full schema as a file from which the introspection fragment matcher can generate information about unions and interfaces.

"hops": {
  "graphqlSchemaFile": "<rootDir>/schema.graphql"
}

allowServerSideDataFetching

If you don't want Hops to do full server-side rendering, set this value to false.

Bear in mind, that setting this value to true on the other hand has no mandatory character. This means that there's no way to force Hops to execute server-side requests. As soon as there's a single Hops preset in place, that either sets the allowServerSideDataFetching-value to false or implements the canPrefetchOnServer-hook to return false, there won't be any server-side requests.

Render Options

This preset has options for controlling the apollo cache and link via the graphql key inside the options object of the render(element, options?) function.

| Name | Type | Default | Required | Description | | --- | --- | --- | --- | --- | | graphql.link | ApolloLink | ApolloHttpLink | no | An instance of an apollo link (e.g. HttpLink) | | graphql.cache | ApolloCache | ApolloCacheInMemory | no | An instance of an apollo cache (e.g. InMemoryCache) |

link

By default this preset creates an HttpLink with the configured graphqlUri. If you need a different link, you can pass the instantiated link to the render options.

Read more about Apollo links here:

• https://www.apollographql.com/docs/link/
• https://www.apollographql.com/docs/react/networking/basic-http-networking/

export default render(<MyApp />, {
  graphql: { link: new HttpLink({ uri: 'http://api.githunt.com/graphql' }) },
});

cache

By default this preset creates an InMemoryCache and passes the fragment types as possibleTypes (create them with $ hops graphql introspect). It also takes care of cache rehydration to pass cached data from a server-side request to the client-side.

In case you need to configure a different Apollo cache you can pass an instantiated cache to the render options.

Read more about Apollo caches here: https://www.apollographql.com/docs/react/caching/cache-configuration/

import possibleTypes from 'hops-react-apollo-preset/fragmentTypes.json';

export default render(<MyApp />, {
  graphql: {
    cache: new InMemoryCache({
      possibleTypes,
    }),
  },
});

Mixin Hooks API

Caution: Please be aware that the mixin hooks are not part of the SemVer API contract. This means that hook methods and signatures can change even in minor releases. Therefore it's up to you to make sure that all hooks that you are using in your own mixins still adhere to the new implementation after an upgrade of a Hops packages.

getApolloLink(): ApolloLink (override) runtime/browser/server

Hook to return a custom ApolloLink.

Useful when the link needs access to the current request object, which only exists in the mixin context.

Beware that link passed as render option takes precedence.

getApolloCache(): ApolloCache (override) runtime/browser/server

Hook to return a custom ApolloCache.

canPrefetchOnServer(): boolean (sequence) server

This is a hook that can be used to customize the behavior of when Hops can prefetch data during server-side rendering. E.g. execute GraphQL queries during initial render. If any function of this sequence returns false it prevents server fetching for this request.

By default it returns whatever is configured in the allowServerSideDataFetching preset option.

In case you need more control over the server-side rendering you can implement this method and provide your own implementation that decides if data should be prefetched during server-side rendering.