v5.2.0

5.2.0 (2021-06-21)

Features

• server: Optional onPing and onPong message type listeners (f36066f)

Server usage with ws and subprotocol pings and pongs

import ws from 'ws'; // yarn add ws
import { makeServer, stringifyMessage, MessageType, CloseCode } from 'graphql-ws';
import { schema } from './my-graphql-schema';

// make
const server = makeServer({ schema });

// create websocket server
const wsServer = new ws.Server({
  port: 4000,
  path: '/graphql',
});

// implement
wsServer.on('connection', (socket, request) => {
  // subprotocol pinger because WS level ping/pongs might not be available
  let pinger, pongWait;
  function ping() {
    if (socket.readyState === socket.OPEN) {
      // send the subprotocol level ping message
      socket.send(stringifyMessage({ type: MessageType.Ping }));

      // wait for the pong for 6 seconds and then terminate
      pongWait = setTimeout(() => {
        clearInterval(pinger);
        socket.close();
      }, 6_000);
    }
  }

  // ping the client on an interval every 12 seconds
  pinger = setInterval(() => ping(), 12_000);

  // a new socket opened, let graphql-ws take over
  const closed = server.opened(
    {
      protocol: socket.protocol, // will be validated
      send: (data) => socket.send(data),
      close: (code, reason) => socket.close(code, reason),
      onMessage: (cb) =>
        socket.on('message', async (event) => {
          try {
            // wait for the the operation to complete
            // - if init message, waits for connect
            // - if query/mutation, waits for result
            // - if subscription, waits for complete
            await cb(event.toString());
          } catch (err) {
            // all errors that could be thrown during the
            // execution of operations will be caught here
            socket.close(CloseCode.InternalServerError, err.message);
          }
        }),
      // pong received, clear termination timeout
      onPong: () => clearTimeout(pongWait),
    },
    // pass values to the `extra` field in the context
    { socket, request },
  );

  // notify server that the socket closed and stop the pinger
  socket.once('close', (code, reason) => {
    clearTimeout(pongWait);
    clearInterval(pinger);
    closed(code, reason);
  });
});