apollo-link-http

What is apollo-link-http?

The apollo-link-http package is used to connect Apollo Client to a GraphQL server over HTTP. It provides a standard way to send GraphQL queries and mutations to a server, handle responses, and manage errors.

What are apollo-link-http's main functionalities?

Basic HTTP Link

This code demonstrates how to create a basic HTTP link to connect to a GraphQL server using the apollo-link-http package. The `createHttpLink` function is used to specify the URI of the GraphQL server, and the link is then used to configure the Apollo Client.

const { createHttpLink } = require('apollo-link-http');
const { ApolloClient, InMemoryCache } = require('@apollo/client');

const httpLink = createHttpLink({
  uri: 'https://example.com/graphql',
});

const client = new ApolloClient({
  link: httpLink,
  cache: new InMemoryCache(),
});

Setting HTTP Headers

This code demonstrates how to set HTTP headers, such as an authorization token, for each request. The `setContext` function from `apollo-link-context` is used to modify the headers before the request is sent.

const { createHttpLink } = require('apollo-link-http');
const { ApolloClient, InMemoryCache } = require('@apollo/client');
const { setContext } = require('apollo-link-context');

const httpLink = createHttpLink({
  uri: 'https://example.com/graphql',
});

const authLink = setContext((_, { headers }) => {
  return {
    headers: {
      ...headers,
      authorization: localStorage.getItem('token') || '',
    }
  };
});

const client = new ApolloClient({
  link: authLink.concat(httpLink),
  cache: new InMemoryCache(),
});

Error Handling

This code demonstrates how to handle errors in GraphQL requests. The `onError` function from `apollo-link-error` is used to log GraphQL and network errors.

const { createHttpLink } = require('apollo-link-http');
const { ApolloClient, InMemoryCache } = require('@apollo/client');
const { onError } = require('apollo-link-error');

const httpLink = createHttpLink({
  uri: 'https://example.com/graphql',
});

const errorLink = onError(({ graphQLErrors, networkError }) => {
  if (graphQLErrors) {
    graphQLErrors.forEach(({ message, locations, path }) => {
      console.log(`GraphQL error: ${message}`);
    });
  }
  if (networkError) {
    console.log(`Network error: ${networkError}`);
  }
});

const client = new ApolloClient({
  link: errorLink.concat(httpLink),
  cache: new InMemoryCache(),
});

Other packages similar to apollo-link-http

apollo-client

Apollo Client is a comprehensive state management library for JavaScript that enables you to manage both local and remote data with GraphQL. It includes functionalities for connecting to a GraphQL server, caching, and error handling, similar to apollo-link-http, but with a broader scope.

relay

Relay is a JavaScript framework for building data-driven React applications. It is similar to apollo-link-http in that it connects to a GraphQL server, but it also includes advanced features like data fetching, caching, and state management, optimized for performance.

urql

urql is a highly customizable and versatile GraphQL client for React. It provides similar functionalities to apollo-link-http, such as connecting to a GraphQL server and handling queries and mutations, but it is designed to be more lightweight and modular.

README

The README file is missing