Initial commit

controllers/longpolling.controller.js

@@ -0,0 +1,109 @@
+const services = require('../services')
+const events = require('events');
+const random_bytes = require('random-bytes');
+
+const emitter = new events.EventEmitter();
+
+const { longpolling } = services
+
+const poll_server_timeout = 20000;
+const poll_client_timeout = 60000;
+
+poll_request_event_identifier = function (id) { return ('poll-request-' + id).toLowerCase(); }
+poll_response_event_identifier = function (qid) { return ('poll-response-' + qid).toLowerCase(); }
+
+poll_request = function (method, action, id, device, data, callback) {
+  function request_listener(message) {
+    ///// Stop timeout
+    clearTimeout(timeout);
+    callback(null, message);
+  };
+
+  ///// Create object
+  object = {
+    method: method,
+    nsip: device || '',
+    action: action || '/',
+    data: JSON.stringify(data).replace(/"/g, "'") || '{}',
+    qid: random_bytes.sync(16).toString('hex')
+  };
+
+  ///// Wait long polling to open
+  emitter.emit(poll_request_event_identifier(id), object);
+
+  ///// Start timeout
+  var timeout = setTimeout(() => {
+    ///// Remove listener
+    emitter.removeListener(poll_response_event_identifier(object.qid), request_listener);
+
+    ///// Send timeout
+    console.log(id + ' did not long poll (' + object.qid + ')');
+    callback('timeout', null);
+  }, poll_client_timeout);
+
+  ///// Listen for event
+  emitter.once(poll_response_event_identifier(object.qid), request_listener);
+}
+
+const postPeriodic = async (req, res, next) => {
+  function listener(message) {
+    ///// Stop timeout
+    clearTimeout(timeout);
+
+    ///// Send response
+    res.send(message);
+  };
+
+  ///// Start timeout
+  var timeout = setTimeout(() => {
+    ///// Remove listener
+    emitter.removeListener(poll_request_event_identifier(req.params.id), listener);
+
+    ///// Send timeout
+    res.sendStatus(408);
+    console.log('Sending timeout to client ' + req.ip + ' (' + req.params.id + ')');
+  }, poll_server_timeout);
+
+  ///// Listen for event
+  emitter.once(poll_request_event_identifier(req.params.id), listener);
+}
+
+const postResponse = async (req, res, next) => {
+  ///// Emit event to client
+  emitter.emit(poll_response_event_identifier(req.params.qid), req.body);
+
+  ///// Response OK
+  res.sendStatus(200);
+}
+
+const getModuleRequest = async (req, res, next) => {
+  ///// Emit event to server
+  url_encoded = req.query;
+  poll_request(req.method, req.params.route, req.params.id, req.params.module, url_encoded, (error, body) => {
+    if (error) { res.send(error); }
+    else { res.send(body); }
+  });
+
+  req.on("close", function () {
+    console.log("Request cancelled by client");
+  });
+}
+
+const postModuleRequest = async (req, res, next) => {
+  ///// Emit event to server
+  poll_request(req.method, req.params.route, req.params.id, req.params.module, req.body, (error, body) => {
+    if (error) { res.send(error); }
+    else { res.send(body); }
+  });
+
+  req.on("close", function () {
+    console.log("Request cancelled by client");
+  });
+}
+
+module.exports = {
+  postPeriodic,
+  postResponse,
+  getModuleRequest,
+  postModuleRequest
+}