feat(handler): Server and environment agnostic handler

[enisdenjo]

Breaking changes

• Core of graphql-sse is now server agnostic and as such offers a handler that implements a generic request/response model
• Handler does not await for whole operation to complete anymore. Only the processing part (parsing, validating and executing)
• GraphQL context is now typed
• Hook arguments have been changed, they're not providing the Node native req/res anymore - they instead provide the generic request/response
• onSubscribe hook can now return an execution result too (useful for caching for example)
• Throwing in onNext and onComplete hooks will bubble the error to the returned iterator

Migration

Even though the core of graphql-sse is now completely server agnostic, there are adapters to ease the integration with existing solutions. Migrating is actually not a headache!

Beware that the adapters don't handle internal errors, it's your responsibility to take care of that and behave accordingly.

http

import http from 'http';
- import { createHandler } from 'graphql-sse';
+ import { createHandler } from 'graphql-sse/lib/use/http';

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

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

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

http2

import fs from 'fs';
import http2 from 'http2';
- import { createHandler } from 'graphql-sse';
+ import { createHandler } from 'graphql-sse/lib/use/http2';

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

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

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

express

import express from 'express'; // yarn add express
- import { createHandler } from 'graphql-sse';
+ import { createHandler } from 'graphql-sse/lib/use/express';

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

// Create an express app
const app = express();

// Serve all methods on `/graphql/stream`
app.use('/graphql/stream', handler);

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

fastify

import Fastify from 'fastify'; // yarn add fastify
- import { createHandler } from 'graphql-sse';
+ import { createHandler } from 'graphql-sse/lib/use/fastify';

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

// Create a fastify app
const fastify = Fastify();

// Serve all methods on `/graphql/stream`
fastify.all('/graphql/stream', handler);

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

TODO

• use/fetch adapter
• use/http adapter
• use/http2 adapter
• use/express adapter
• use/fastify adapter
• Update documentation
• Migration steps

[enisdenjo]

🎉 This PR is included in version 2.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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