WebRTC Signalling Server for Real-Time Robot Control

Overview of Project

This repository is part of the Online Robot Remote Control project where users can log in to a website to remotely control one of any number of robots in a fleet from the comfort of their homes using WebRTC.

This repository contains the Signalling Server, which handles signalling for webRTC connection requests from a client on a device to a remotely controlled robot. This involves managing the offers and answers sent between the frontend instances and the available robots. It also managed the queueing of the users as they wait for their turn to control a robot.

Other Repositories

• Frontend
• Robot Control

Setup for Full Signalling Server

• Install nodejs
• Setup TURN server using coTURN with the following instructions.
  • This is needed by webRTC to go through firewalls. Both the client frontend and robot need to know the IP:port for this server
• Run the script using the node server.js command

Setup for Local Testing

• Only requires running the script using node server.js

Function Reference

robotLoginHandler(data, connection)

Use When a robot switches on, it sends a connection request that triggers this function. The function saves the robot information in an object/map called connectedRobots with the key as the robot name and the value being the robot connection object. It also appends a joinedGame parameter to the connection object to signify which game this robot is available to clients under.

Parameters data: Object of format:

{ 
    type: "robot-login", 
    name: <RobotNameString>,        // Unique identifier for robot
    joinedGame: "<GameNameString>   // Which game this robot will be available under
}

connection: The robot connection object returned by WebSocket

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userLoginHandler(data, connection)

Use When a client logs into the frontend from their browser, this function is called. It stores the client data in an object/map called connectedUsers with the key as the user name and the value being the user connection object. This data is later used by other functions to link up a robot and client together in a webRTC stream. It also performs a check if a user has entered a duplicate username as another user already connected.

Parameters data: Object of format:

{ 
    type: "user-login",     
    name: <UserNameString>, // Unique identifier for user (previously entered by user in frontend)
}

connection: The user connection object returned by WebSocket

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The other functions follow the same design pattern as above, where they are called from a single switch/case statement depending on what query the user has entered.