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I am working in chessboard.js for creating a multyplayer chessboard using signalR. but i am having a problem in player movement.

what i am doing is sending the FEN string from client1 to client2.and Thus client2 represent that FEN string on board. Now the problem is that the player2 represent the FEN on Board but player turn is not changed by FEN. So both Player 1 and 2 move white first then black secondly.and that is not to be supposed.

i want Player1 moves from white side.His FEN is send To Player2.then Player2 will Move with Black Color (but currently player2 move with white which is error). So please help me how to change the turn of player1 or player2 forcely.

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1 Answers1

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I was struggling with the same issue when creating a similar multiplayer chess game using chessboard.js along with chess.js (the engine running the actual game rules)

The answer lies within the chess.js file that is referenced on the chessboard.js api documentation.

Line 157 of chess.js has this:

   var turn = WHITE;

If you wish to change the turn of the whole game you can simply do this:

turn = BLACK;
turn = WHITE;
turn = "w";
turn = "b";

Any of them will work. I also created a convenience function that can be more easily used by other scripts which adds setTurn() and turn() to the public API..

Convenience function to add to API for turn manipulation:


Around line 1115 of chess.js (not chessboard.js), you will find a function that starts off with:

return {
/***************************************************************************
 * PUBLIC CONSTANTS (is there a better way to do this?)
 **************************************************************************

I simply added The following to right below the comment:

turn: function() {
   return turn;
},
setTurn: function(newTurn) {
    turn = newTurn;
},

The result is that now from either any instance of chess.js (default name is game), you can simply change turns like this:

game.setTurn("b");
game.setTurn("w");

This is but one hurdle that I ran into while making a multiplayer version. The next hurdle you will likely face is going to be: what happens if a player gets disconnected or doesn't respond? How about if they inject a JS file into the page that allows them to change turns at will? These issues will be more of a pain to solve. Also look out for other types of injection attacks such as manipulation of the game FEN externally.

Good luck!

Leave comment if you want me to share my source code -- I figured out most of the issues that come up with chessboard.js as multiplayer.

mike510a
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  • hey Mike Nickaloff thanks. For your rply.yes.it will be more hepfull ,if you share your source code.. –  Apr 25 '16 at 02:55
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    The solution is Javascript using workers and websockets combined with a C++ backend to keep things in order. Which part of the code do you want? Its fairly extensive.. ... you can view the javascript front-end source code at http://chess.datafault.net/?cpu=1 (you can play with your friends too by going to http://chess.datafault.net/ and then sending them the link at the bottom) – mike510a Apr 30 '16 at 15:05
  • thanks ,. Would you tell me/Instructme/Send me sourcecode for attaching chess engine (stockfish etc.) in chess game.Actucally i had used cinnamon javascript chess engine,which is not fast as it should be..vimalraturi.ntl@gmail.com –  May 02 '16 at 02:35
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    @vimal raturi -- well if you wanted to attach a chess engine from say a 3rd party library, it would depend on what language that library was written in -- for example if it was C++ then you could have it running as a daemon natively and then use websockets to connect to the daemon from javascript whenever you wanted to have the computer make a move, at which point the C++ program running would perform the necessary calculations to formulate a move, at which point you have the daemon send the desired move back to the javascript thru that socket and then make the move. – mike510a May 09 '16 at 04:01