graphql-helix

import express from 'express'; import { buildSchema } from 'graphql'; import { getGraphQLParameters, processRequest, renderGraphiQL, shouldRenderGraphiQL, } from 'graphql-helix'; const schema = buildSchema(` type Query { hello: String } type Subscription { greeting: String } `); const rootValue = { hello: () => 'Hello GraphQL Helix!', greeting: async function* () { for (const hi of ['Hi', 'Bonjour', 'Hola', 'Ciao']) { yield { greeting: hi }; await new Promise(resolve => setTimeout(resolve, 500)); } }, }; const app = express(); app.use(express.json()); app.use('/graphql', async (req, res) => { const request = { body: req.body, headers: req.headers, method: req.method, query: req.query, }; if (shouldRenderGraphiQL(request)) { res.send(renderGraphiQL()); } else { const { operationName, query, variables } = getGraphQLParameters(request); const result = await processRequest({ operationName, query, variables, request, schema, contextFactory: () => ({ request }), rootValue, }); if (result.type === 'RESPONSE') { result.headers.forEach(({ name, value }) => res.setHeader(name, value)); res.status(result.status); res.json(result.payload); } else if (result.type === 'MULTIPART_RESPONSE') { res.writeHead(200, { Connection: 'keep-alive', 'Content-Type': 'multipart/mixed; boundary="-"', 'Transfer-Encoding': 'chunked', }); req.on('close', () => { result.unsubscribe(); }); res.write('---'); for await (const chunk of result.subscribe()) { res.write(`\r\n${JSON.stringify(chunk)}\r\n---`); } res.end(); } else if (result.type === 'PUSH') { res.writeHead(200, { 'Content-Type': 'text/event-stream', Connection: 'keep-alive', 'Cache-Control': 'no-cache', }); req.on('close', () => { result.unsubscribe(); }); for await (const event of result.subscribe()) { res.write(`data: ${JSON.stringify(event)}\n\n`); } } } }); app.listen(4000, () => console.log('GraphQL server running on http://localhost:4000/graphql'));