MQTT over TCP as an optional transport

You want to:

• report a bug
• request a feature

Status quo

"Transport" only supports ['polling', 'websocket']

Expected implementation

"Transport" supports ['polling', 'websocket', 'mqtt']

Rationale

When developing mobile apps (aka non-web), MQTT over TCP performs much better than HTTP (polling, websocket, or MQTT over websocket), however, like the adoption of websocket, MQTT over TCP might be stopped by firewall. In an ideal scenario, app developers should not care about the transportation, but focus on the logic. Transportation layer should gracefully chooses the best method, given the conditions. Ref https://www.quora.com/Is-MQTT-better-than-HTTP-for-mobile-app-iOS-Android-etc-client-server-communication

Other information:

• If this issue is approved, I can research how to optionally use https://github.com/mqttjs/MQTT.js as one of the transport method, e.g ['polling', 'websocket', require('mqtt-engine')]

Start by reviewing Socket.IO's existing polling and websocket transport handling, then examine how MQTT.js could be integrated as an optional transport. Done means transport selection can include MQTT over TCP without breaking the existing polling or websocket options, with the relevant behavior covered by tests.