npm:@ojshua/zmq-request

README

zeromq REQ with renewed socket and Promise response

This package wraps a REQ socket from the zeromq package.

Reusing the same REQ socket for repeating requests in an async environment (Node.js) is not easy, as 0MQ requires to read the reply before sending a new one.

This package opens a new socket, sends the request, waits for the reply, closes the socket and resolves the Promise.

const
  log = console.log,
  Request = require('zmq-request'),
  zmq = require('zeromq');

// minimal echo server
rep = zmq.socket('rep').bindSync('tcp://*:3000');
rep.on('message', raw => rep.send(raw));

const request = new Request({ port: 3000 });
request
  .send({ ok: true })
  .then(log)   // { ok: true }
  .catch(log)
  .then(() => rep.close())

Multiple parallel requests

const
  log = console.log,
  Request = require('zmq-request'),
  zmq = require('zeromq');

// minimal echo server
rep = zmq.socket('rep').bindSync('tcp://*:3000');
rep.on('message', raw => rep.send(raw));

const request = new Request({ port: 3000 });
Promise.all([
  request.send({ data: 1 }),
  request.send({ data: 2 }),
  request.send({ data: 3 }),
  request.send({ data: 4 }),
  request.send({ data: 5 })
])
  .then(log)  // [ { data: 1 }, { data: 2 }, { data: 3 }, { data: 4 }, { data: 5 } ]
  .catch(log)
  .then(() => rep.close());

Usage no npm install needed!

README