graphql-http

graphql-http

Simple, pluggable, zero-dependency, GraphQL over HTTP Protocol compliant server and client.

Need subscriptions? Try graphql-ws or graphql-sse instead!

Getting started

Install

yarn add graphql-http

Create a GraphQL schema

import { GraphQLSchema, GraphQLObjectType, GraphQLString } from 'graphql';

/**
 * Construct a GraphQL schema and define the necessary resolvers.
 *
 * type Query {
 *   hello: String
 * }
 */
const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'Query',
    fields: {
      hello: {
        type: GraphQLString,
        resolve: () => 'world',
      },
    },
  }),
});

Start the server

With http

import http from 'http';
import { createHandler } from 'graphql-http';
import { schema } from './previous-step';

// Create the GraphQL over HTTP handler
const handler = createHandler({ schema });

// Create a HTTP server using the handler on `/graphql`
const server = http.createServer(async (req, res) => {
  if (!req.url.startsWith('/graphql')) {
    return res.writeHead(404).end();
  }

  try {
    const [body, init] = await handler({
      url: req.url,
      method: req.method,
      headers: req.headers,
      body: await new Promise((resolve) => {
        let body = '';
        req.on('data', (chunk) => (body += chunk));
        req.on('end', () => resolve(body));
      }),
      raw: req,
    });
    res.writeHead(init.status, init.statusText, init.headers).end(body);
  } catch (err) {
    res.writeHead(500).end(err.message);
  }
});

server.listen(4000);
console.log('Listening to port 4000');

With http2

Browsers might complain about self-signed SSL/TLS certificates. Help can be found on StackOverflow.

$ openssl req -x509 -newkey rsa:2048 -nodes -sha256 -subj '/CN=localhost' \
  -keyout localhost-privkey.pem -out localhost-cert.pem

import fs from 'fs';
import http2 from 'http2';
import { createHandler } from 'graphql-http';
import { schema } from './previous-step';

// Create the GraphQL over HTTP handler
const handler = createHandler({ schema });

// Create a HTTP/2 server using the handler on `/graphql`
const server = http2.createSecureServer(
  {
    key: fs.readFileSync('localhost-privkey.pem'),
    cert: fs.readFileSync('localhost-cert.pem'),
  },
  async (req, res) => {
    if (!req.url.startsWith('/graphql')) {
      return res.writeHead(404).end();
    }

    try {
      const [body, init] = await handler({
        url: req.url,
        method: req.method,
        headers: req.headers,
        body: await new Promise((resolve) => {
          let body = '';
          req.on('data', (chunk) => (body += chunk));
          req.on('end', () => resolve(body));
        }),
        raw: req,
      });
      res.writeHead(init.status, init.statusText, init.headers).end(body);
    } catch (err) {
      res.writeHead(500).end(err.message);
    }
  },
);

server.listen(4000);
console.log('Listening to port 4000');

With express

import express from 'express'; // yarn add express
import { createHandler } from 'graphql-http';
import { schema } from './previous-step';

// Create the GraphQL over HTTP handler
const handler = createHandler({ schema });

// Create an express app serving all methods on `/graphql`
const app = express();
app.use('/graphql', async (req, res) => {
  try {
    const [body, init] = await handler({
      url: req.url,
      method: req.method,
      headers: req.headers,
      body: await new Promise((resolve) => {
        let body = '';
        req.on('data', (chunk) => (body += chunk));
        req.on('end', () => resolve(body));
      }),
      raw: req,
    });
    res.writeHead(init.status, init.statusText, init.headers).end(body);
  } catch (err) {
    res.writeHead(500).end(err.message);
  }
});

app.listen(4000);
console.log('Listening to port 4000');

With fastify

import Fastify from 'fastify'; // yarn add fastify
import { createHandler } from 'graphql-http';
import { schema } from './previous-step';

// Create the GraphQL over HTTP handler
const handler = createHandler({ schema });

// Create a fastify instance serving all methods on `/graphql`
const fastify = Fastify();
fastify.all('/graphql', async (req, res) => {
  try {
    const [body, init] = await handler({
      url: req.url,
      method: req.method,
      headers: req.headers,
      body: await new Promise((resolve) => {
        let body = '';
        req.on('data', (chunk) => (body += chunk));
        req.on('end', () => resolve(body));
      }),
      raw: req,
    });
    res.writeHead(init.status, init.statusText, init.headers).end(body);
  } catch (err) {
    res.writeHead(500).end(err.message);
  }
});

fastify.listen(4000);
console.log('Listening to port 4000');

With Deno

import { serve } from 'https://deno.land/std@0.151.0/http/server.ts';
import { createHandler } from 'https://esm.sh/graphql-http';
import { schema } from './previous-step';

// Create the GraphQL over HTTP handler
const handler = createHandler<Request>({ schema });

// Start serving on `/graphql` using the handler
await serve(
  async (req: Request) => {
    const [path, _search] = req.url.split('?');
    if (!path.endsWith('/graphql')) {
      return new Response(null, { status: 404, statusText: 'Not Found' });
    }

    const headers: Record<string, string> = {};
    req.headers.forEach((value, key) => (headers[key] = value));
    const [body, init] = await handler({
      url: req.url,
      method: req.method,
      headers,
      body: await req.text(),
      raw: req,
    });
    return new Response(body, init);
  },
  {
    port: 4000,
  },
);

// Listening to port 4000

Use the client

import { createClient } from 'graphql-http';

const client = createClient({
  url: 'http://localhost:4000/graphql',
});

(async () => {
  let cancel = () => {
    /* abort the request if it is in-flight */
  };

  const result = await new Promise((resolve, reject) => {
    let result;
    cancel = client.subscribe(
      {
        query: '{ hello }',
      },
      {
        next: (data) => (result = data),
        error: reject,
        complete: () => resolve(result),
      },
    );
  });

  expect(result).toEqual({ hello: 'world' });
})();

Recipes

🔗 Client usage with Promise

import { ExecutionResult } from 'graphql';
import { createClient, RequestParams } from 'graphql-http';
import { getSession } from './my-auth';

const client = createClient({
  url: 'http://hey.there:4000/graphql',
  headers: async () => {
    const session = await getSession();
    if (session) {
      return {
        Authorization: `Bearer ${session.token}`,
      };
    }
  },
});

function execute<Data, Extensions>(
  params: RequestParams,
): [request: Promise<ExecutionResult<Data, Extensions>>, cancel: () => void] {
  let cancel!: () => void;
  const request = new Promise<ExecutionResult<Data, Extensions>>(
    (resolve, reject) => {
      let result: ExecutionResult<Data, Extensions>;
      cancel = client.subscribe<Data, Extensions>(params, {
        next: (data) => (result = data),
        error: reject,
        complete: () => resolve(result),
      });
    },
  );
  return [request, cancel];
}

(async () => {
  const [request, cancel] = execute({
    query: '{ hello }',
  });

  // just an example, not a real function
  onUserLeavePage(() => {
    cancel();
  });

  const result = await request;

  expect(result).toBe({ data: { hello: 'world' } });
})();

🔗 Client usage with Observable

import { Observable } from 'relay-runtime';
// or
import { Observable } from '@apollo/client/core';
// or
import { Observable } from 'rxjs';
// or
import Observable from 'zen-observable';
// or any other lib which implements Observables as per the ECMAScript proposal: https://github.com/tc39/proposal-observable
import { createClient } from 'graphql-http';
import { getSession } from './my-auth';

const client = createClient({
  url: 'http://graphql.loves:4000/observables',
  headers: async () => {
    const session = await getSession();
    if (session) {
      return {
        Authorization: `Bearer ${session.token}`,
      };
    }
  },
});

const observable = new Observable((observer) =>
  client.subscribe({ query: '{ hello }' }, observer),
);

const subscription = observable.subscribe({
  next: (result) => {
    expect(result).toBe({ data: { hello: 'world' } });
  },
});

// unsubscribe will cancel the request if it is pending
subscription.unsubscribe();

🔗 Client usage with Relay

import { GraphQLError } from 'graphql';
import {
  Network,
  Observable,
  RequestParameters,
  Variables,
} from 'relay-runtime';
import { createClient } from 'graphql-http';
import { getSession } from './my-auth';

const client = createClient({
  url: 'http://i.love:4000/graphql',
  headers: async () => {
    const session = await getSession();
    if (session) {
      return {
        Authorization: `Bearer ${session.token}`,
      };
    }
  },
});

function fetch(operation: RequestParameters, variables: Variables) {
  return Observable.create((sink) => {
    if (!operation.text) {
      return sink.error(new Error('Operation text cannot be empty'));
    }
    return client.subscribe(
      {
        operationName: operation.name,
        query: operation.text,
        variables,
      },
      sink,
    );
  });
}

export const network = Network.create(fetch);

🔗 Client usage with Apollo

import {
  ApolloLink,
  Operation,
  FetchResult,
  Observable,
} from '@apollo/client/core';
import { print, GraphQLError } from 'graphql';
import { createClient, ClientOptions, Client } from 'graphql-http';
import { getSession } from './my-auth';

class HTTPLink extends ApolloLink {
  private client: Client;

  constructor(options: ClientOptions) {
    super();
    this.client = createClient(options);
  }

  public request(operation: Operation): Observable<FetchResult> {
    return new Observable((sink) => {
      return this.client.subscribe<FetchResult>(
        { ...operation, query: print(operation.query) },
        {
          next: sink.next.bind(sink),
          complete: sink.complete.bind(sink),
          error: sink.error.bind(sink),
        },
      );
    });
  }
}

const link = new HTTPLink({
  url: 'http://where.is:4000/graphql',
  headers: async () => {
    const session = await getSession();
    if (session) {
      return {
        Authorization: `Bearer ${session.token}`,
      };
    }
  },
});

🔗 Client usage with request retries

import { createClient, NetworkError } from 'graphql-http';

const client = createClient({
  url: 'http://unstable.service:4000/graphql',
  shouldRetry: async (err: NetworkError, retries: number) => {
    if (retries > 3) {
      // max 3 retries and then report service down
      return false;
    }

    // try again when service unavailable, could be temporary
    if (err.response?.status === 503) {
      // wait one second (you can alternatively time the promise resolution to your preference)
      await new Promise((resolve) => setTimeout(resolve, 1000));
      return true;
    }

    // otherwise report error immediately
    return false;
  },
});

🔗 Client usage in browser

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>GraphQL over HTTP</title>
    <script
      type="text/javascript"
      src="https://unpkg.com/graphql-http/umd/graphql-http.min.js"
    ></script>
  </head>
  <body>
    <script type="text/javascript">
      const client = graphqlHttp.createClient({
        url: 'http://umdfor.the:4000/win/graphql',
      });

      // consider other recipes for usage inspiration
    </script>
  </body>
</html>

🔗 Client usage in Node

const fetch = require('node-fetch'); // yarn add node-fetch
const { AbortController } = require('node-abort-controller'); // (node < v15) yarn add node-abort-controller
const { createClient } = require('graphql-http');

const client = createClient({
  url: 'http://no.browser:4000/graphql',
  fetchFn: fetch,
  abortControllerImpl: AbortController, // node < v15
});

// consider other recipes for usage inspiration

🔗 Client usage in Deno

import { createClient } from 'graphql-http';

const client = createClient({
  url: 'http://deno.earth:4000/graphql',
});

// consider other recipes for usage inspiration

🔗 Server handler usage with authentication

Authenticate the user within graphql-http during GraphQL execution context assembly. This is a approach is less safe compared to early authentication (see early authentication in Node) because some GraphQL preparations or operations are executed even if the user is not unauthorized.

import { createHandler } from 'graphql-http';
import {
  schema,
  getUserFromCookies,
  getUserFromAuthorizationHeader,
} from './my-graphql';

const handler = createHandler({
  schema,
  context: async (req) => {
    // process token, authenticate user and attach it to your graphql context
    const userId = await getUserFromCookies(req.headers.cookie);
    // or
    const userId = await getUserFromAuthorizationHeader(
      req.headers.authorization,
    );

    // respond with 401 if the user was not authenticated
    if (!userId) {
      return [null, { status: 401, statusText: 'Unauthorized' }];
    }

    // otherwise attach the user to the graphql context
    return { userId };
  },
});

🔗 Server handler usage with custom context value

import { createHandler } from 'graphql-http';
import { schema, getDynamicContext } from './my-graphql';

const handler = createHandler({
  schema,
  context: async (req, args) => {
    return getDynamicContext(req, args);
  },
  // or static context by supplying the value direcly
});

🔗 Server handler usage with custom execution arguments

import { parse } from 'graphql';
import { createHandler } from 'graphql-http';
import { getSchemaForRequest, myValidationRules } from './my-graphql';

const handler = createHandler({
  onSubscribe: async (req, params) => {
    const schema = await getSchemaForRequest(req);

    const args = {
      schema,
      operationName: params.operationName,
      document: parse(params.query),
      variableValues: params.variables,
    };

    return args;
  },
});

🔗 Server handler usage in Node with early authentication (recommended)

Authenticate the user early, before reaching graphql-http. This is the recommended approach because no GraphQL preparations or operations are executed if the user is not authorized.

import { createHandler } from 'graphql-http';
import {
  schema,
  getUserFromCookies,
  getUserFromAuthorizationHeader,
} from './my-graphql';

const handler = createHandler({
  schema,
  context: async (req) => {
    // user is authenticated early (see below), simply attach it to the graphql context
    return { userId: req.raw.userId };
  },
});

const server = http.createServer(async (req, res) => {
  if (!req.url.startsWith('/graphql')) {
    return res.writeHead(404).end();
  }

  try {
    // process token, authenticate user and attach it to the request
    req.userId = await getUserFromCookies(req.headers.cookie);
    // or
    req.userId = await getUserFromAuthorizationHeader(
      req.headers.authorization,
    );

    // respond with 401 if the user was not authenticated
    if (!req.userId) {
      return res.writeHead(401, 'Unauthorized').end();
    }

    const [body, init] = await handler({
      url: req.url,
      method: req.method,
      headers: req.headers,
      body: await new Promise((resolve) => {
        let body = '';
        req.on('data', (chunk) => (body += chunk));
        req.on('end', () => resolve(body));
      }),
      raw: req,
    });
    res.writeHead(init.status, init.statusText, init.headers).end(body);
  } catch (err) {
    res.writeHead(500).end(err.message);
  }
});

server.listen(4000);
console.log('Listening to port 4000');

Documentation

Check the docs folder out for TypeDoc generated documentation.

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