Controldev Websocket

A websocket-based proxy for controldev commands, and associated javascript to read the data from the Gamepad API and send it there.

Task

This component just have one task, called Task, which is the websocket server. The server receives a JSON message and tries to build a controldev/RawCommand to send over raw_command port.

Also, the first message sent by the websocket client should be handshake with a JSON containing just a test_message with the original command inside it like:

{
    "test_message": {
        "buttons": { ... },
        "axes": { ... },
        "time": 123 // time in ms
    }
}

In addition, the task has a statistics port sending controldev_websocket/Statistics with received and errors fields counting incoming messages and failures to build a controldev/RawCommand with it.

Connection messages

When opening the websocket connection your client will be at the pending state. The state will advance to controlling only after the handshake message. It is valid to remember that the server stores only one pending and one controlling connection. Everytime a new connection is made this server will return a message informing if stole the connection from someone else or if it is new. Also, everytime a connection is closed because other stole it a message might be sent to the client before informing that it lost the connection. The messages have a "peer" field indicating the id of the other related client.

The message is as follows:

• When just created and no one was pending:

  {
      connection_state: {
          state: "new"
      }
  }
  

• When just created and other was pending:

  {
      connection_state: {
          state: "stolen",
          peer: "pending connection"
      }
  }
  

• When pending and other was created:

  {
      connection_state: {
          state: "lost",
          peer: "pending connection"
      }
  }
  

• When goes to controlling and other was there:

  {
      connection_state: {
          state: "stolen",
          peer: "$OTHER_ID"
      }
  }
  

• When is controlling and a pending steal it:

  {
      connection_state: {
          state: "lost",
          peer: "$PENDING_ID"
      }
  }
  

Configuration

The Task has 3 properties:

• port: Is the server port, default to 58000.
• axis_map: Is the axis mapping from WebSocket axes to RawCommand.axisValue. Type is a vector of controldev_websocket/Mapping.
• button_map: Is the button mapping from WebSocket buttons to RawCommand.buttonValue. Type is a vector of controldev_websocket/ButtonMapping.

The default configuration used in the example is:

--- name:default

axis_map:
  - index: 0
    type: Axis
  - index: 1
    type: Axis
  - index: 6
    type: Button
  - index: 2
    type: Axis
  - index: 3
    type: Axis
  - index: 7
    type: Button

button_map:
  - index: 0
    type: Button
    threshold: 0.5
  - index: 1
    type: Button
    threshold: 0.5
  - index: 2
    type: Button
    threshold: 0.5
  - index: 3
    type: Button
    threshold: 0.5
  - index: 4
    type: Button
    threshold: 0.5
  - index: 5
    type: Button
    threshold: 0.5
  - index: 8
    type: Button
    threshold: 0.5
  - index: 9
    type: Button
    threshold: 0.5
  - index: 10
    type: Button
    threshold: 0.5
  - index: 11
    type: Button
    threshold: 0.5
  - index: 12
    type: Button
    threshold: 0.5
  - index: 13
    type: Button
    threshold: 0.5
  - index: 14
    type: Button
    threshold: 0.5

To help figuring out the configuration and axis mappings, you can open examples/gamepad.html in your browser. Note that browsers nowadays wait for a physical button to be pressed on the gamepad before they export them to the javascript code (to avoid fingerprinting).

Usage

At the examples folder has the necessary files to run the component (server) within a bundle and a simple HTML page to run the client GamepadStream object.

Note, the GamepadStream object is defined in gamepad_stream.ts file and then the TypeScript code is 'compiled' using tsc gamepad_stream.ts command resulting the gamepad_stream.js used at the HTML file.

To run the server just inside a bundle run (you might have the config file at this bundle):

syskit run ../../drivers/orogen/controldev_websocket/examples/run.rb -c

Then, simply open the stream.html in your browser, connect a gamepad and enjoy it. To run it from another computer replace the localhost in HTML file with the server IP address.