node-haxball/examples/plugins/controlOtherPlayers.js

The most powerful and lightweight API that allows you to develop your original Haxball(www.haxball.com) host, client, and standalone applications both on node.js and browser environments and also includes every possible hack and functionality that you can

module.exports = function(API){
  const { OperationType, VariableType, ConnectionState, AllowFlags, Direction, CollisionFlags, CameraFollow, BackgroundType, GamePlayState, BanEntryType, Callback, Utils, Room, Replay, Query, Library, RoomConfig, Plugin, Renderer, Errors, Language, EventFactory, Impl } = API;

  Object.setPrototypeOf(this, Plugin.prototype);
  Plugin.call(this, "controlOtherPlayers", true, { // "controlOtherPlayers" is plugin's name, "true" means "activated just after initialization". Every plugin should have a unique name.
    version: "0.1",
    author: "abc",
    description: `This plugin lets you take control of every player in the room. This should be improved with a permission mechanism.
    Available commands: 
    - !control [id]: Take control of the player whose playerId=[id].
    - !blockControl [id] [value={0, 1}]: Block/unblock taking control of the player whose playerId=[id].`,
    allowFlags: AllowFlags.CreateRoom // We allow this plugin to be activated on CreateRoom only.
  });

  var controlSwitch = {}, controlSwitchBlocked = {}, that = this;

  this.finalize = function(){
    controlSwitch = null;
    controlSwitchBlocked = null;
  };

  var setControlledPlayer = function(byPlayerId, playerIdToBeControlled){
    if (isNaN(byPlayerId) || isNaN(playerIdToBeControlled) || controlSwitchBlocked[playerIdToBeControlled])
      return;
    /*
    if (!controlPermitted[byPlayerId]) // example for custom permission logic
      return;
    */
    if (!that.room.getPlayer(playerIdToBeControlled))
      playerIdToBeControlled = byPlayerId;
    controlSwitch[byPlayerId] = playerIdToBeControlled;
  };

  var blockControlPlayer = function(byPlayerId, playerId, value){
    if (isNaN(playerId))
      return;
    /*
    if (!blockControlPermitted[byPlayerId]) // example for custom permission logic
      return;
    */
    if (!that.room.getPlayer(playerId))
      return;
    controlSwitchBlocked[playerId] = (value == 1);
  };

  this.onOperationReceived = function(type, msg, globalFrameNo, clientFrameNo, customData){
    var playerId = msg.byId;
    var cs = controlSwitch[playerId];
    if (cs != null && !controlSwitchBlocked[playerId]) // if the player is marked to be controlled by someone else, and the player has not protected himself being controlled,
      msg.byId = cs; // this is where the magic happens: modify event's player id so that it will look like it has come from someone else.
    switch (type){
      case OperationType.SendChat:{
        /*
        var m = msg.text;
        if (m.startsWith("!")){  // custom chat logic for extra commands
        */
        if (customData?.isCommand){ // same as above 2 lines.
          var arr = customData.data; // same as var arr = m.trimEnd().split(" ");
          switch (arr[0]){
            case "!control":
              setControlledPlayer(playerId, parseInt(arr[1])); // must use original playerId to be able to take back control of your own player
              break;
            case "!blockControl":
              blockControlPlayer(playerId, parseInt(arr[1]), parseInt(arr[2])); // must use original playerId to be able to take back control of your own player
              break;
          }
          //return false; // do not block this event from being processed. it is done automatically in onAfterOperationReceived. 
        }
        break;
      }
    }
    return true;
  };

  this.onPlayerLeave = function(playerObj, reason, isBanned, byId, customData){
    // get player's id
    var id = playerObj.id;

    // free extra memory allocated
    delete controlSwitch[id];
    delete controlSwitchBlocked[id];
  };
};