onspli/chess

PHP library for reading and editing FEN and PGN chess formats.

Features

FEN class

• load FEN representing chess position (standard or Shredder-FEN)
• read and modify all FEN fields
• export FEN
• read and set piece placement
• get or set piece on any square
• test position for check, mate, stalemate
• test position for fifty-move rule
• perform move in given position
• test if move is legal in given position
• list all legal moves in given position
• supports Fisher's random (Chess960)

PGN class

• load PGN representing chess game
• read and set all tag pairs (PGN headers)
• export PGN
• read and add moves
• get FEN position after any move
• supports Fisher's random (Chess960)

Installation

Install with composer:

composer require onspli/chess

Usage

Read complete auto-generated documentation or learn from the following examples.

Setup chess board to starting position and read FEN fields.

$fen = new Onspli\Chess\FEN;
echo($fen->export());
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
echo($fen->export_short());
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -
echo($fen->get_board());
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR
echo($fen->get_active_color());
// w
echo($fen->get_castling());
// KQkq
echo($fen->get_en_passant());
// -
echo($fen->get_halfmove());
// 0
echo($fen->get_fullmove());
// 1
echo($fen->preview());
/*
rnbqkbnr
pppppppp
........
........
........
........
PPPPPPPP
RNBQKBNR
*/

Initialize custom position and read FEN fields.

$fen = new Onspli\Chess\FEN('rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR b KQq c6 1 2');
echo($fen->export());
// rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR b KQq c6 1 2
echo($fen->export_short());
// rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR b KQq c6
echo($fen->get_board());
// rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR
echo($fen->get_active_color());
// b
echo($fen->get_castling());
// KQq
echo($fen->get_en_passant());
// c6
echo($fen->get_halfmove());
// 1
echo($fen->get_fullmove());
// 2
echo($fen->preview());
/*
rnbqkbnr
pp.ppppp
........
..p.....
....P...
........
PPPP.PPP
RNBQKBNR
*/

Manipulate with pieces.

$fen = new Onspli\Chess\FEN;
echo($fen->get_square('a1'));
// R
$fen->set_square('a1', '');
$fen->set_square('a3', 'R');
echo($fen->preview());
/*
rnbqkbnr
pppppppp
........
........
........
R.......
PPPPPPPP
.NBQKBNR
*/

Each of the fields can be set with the corresponding setter:

$fen = new Onspli\Chess\FEN;
echo($fen->export());
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
$fen->set_board('rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR');
$fen->set_active_color('b');
$fen->set_castling('KQq');
$fen->set_en_passant('c6');
$fen->set_halfmove(1);
$fen->set_fullmove(2);
echo($fen->export());
// rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR b KQq c6 1 2
echo($fen->preview());
/*
rnbqkbnr
pp.ppppp
........
..p.....
....P...
........
PPPP.PPP
RNBQKBNR
*/

Perform moves:

$fen = new Onspli\Chess\FEN;
echo($fen->preview());
/*
rnbqkbnr
pppppppp
........
........
........
........
PPPPPPPP
RNBQKBNR
*/
$fen->move('e4');
$fen->move('g6');
$fen->move('Nf3');
$fen->move('Nf6');
$fen->move('Bc4');
$fen->move('Bg7');
$fen->move('O-O');
$fen->move('O-O');
echo($fen->preview());
/*
rnbq.rk.
ppppppbp
.....np.
........
..B.P...
.....N..
PPPP.PPP
RNBQ.RK.
*/
echo($fen->export());
// rnbq1rk1/ppppppbp/5np1/8/2B1P3/5N2/PPPP1PPP/RNBQ1RK1 w - - 6 5

Test check, mate, stalemate:

$fen = new Onspli\Chess\FEN;
$fen->set_active_color('w');
$fen->set_board('1q5k/8/8/8/8/8/8/K7');
$fen->set_castling('-');
echo($fen->is_check() ? 'true' : 'false');
// false
echo($fen->is_stalemate() ? 'true' : 'false');
// false
echo($fen->preview());
/*
.q.....k
........
........
........
........
........
........
K.......
*/
$fen->move('Ka2');
$fen->move('Qa8');
echo($fen->is_check() ? 'true' : 'false');
// true
echo($fen->is_mate() ? 'true' : 'false');
// false
echo($fen->preview());
/*
q......k
........
........
........
........
........
K.......
........
*/

List all possible moves:

$fen = new Onspli\Chess\FEN;
$fen->move('e4');
$fen->move('g6');
echo($fen->preview());
/*
rnbqkbnr
pppppp.p
......p.
........
....P...
........
PPPP.PPP
RNBQKBNR
*/
print_r($fen->get_legal_moves());
/*
Array
(
    [0] => a4
    [1] => a3
    [2] => b4
    [3] => b3
    [4] => c4
    [5] => c3
    [6] => d4
    [7] => d3
    [8] => f4
    [9] => f3
    [10] => g4
    [11] => g3
    [12] => h4
    [13] => h3
    [14] => e5
    [15] => Nc3
    [16] => Na3
    [17] => Ne2
    [18] => Nh3
    [19] => Nf3
    [20] => Be2
    [21] => Bd3
    [22] => Bc4
    [23] => Bb5
    [24] => Ba6
    [25] => Qe2
    [26] => Qf3
    [27] => Qg4
    [28] => Qh5
    [29] => Ke2
)

*/

Load game in PGN notation and read tags and moves:

$pgn = new Onspli\Chess\PGN('[Event "Testing"] 1.Nf3 Nf6 2.c4 g6');
echo($pgn->get_tag('Event'));
// Testing
echo($pgn->get_halfmove(2));
// Nf6
echo($pgn->get_initial_halfmove_number());
// 1
echo($pgn->get_last_halfmove_number());
// 4

Record new moves, add tags and export PGN:

$pgn = new Onspli\Chess\PGN('[Event "Testing"] 1.Nf3 Nf6 2.c4 g6');
$pgn->set_tag('Site', 'Github');
$pgn->move('a4');
$pgn->move('a5');
print_r($pgn->get_tags());
/*
Array
(
    [Event] => Testing
    [Site] => Github
)

*/
echo($pgn->export_tags());
/*
[Event "Testing"]
[Site "Github"]

*/
echo($pgn->export_movetext());
// 1. Nf3 Nf6 2. c4 g6 3. a4 a5
echo($pgn->export());
/*
[Event "Testing"]
[Site "Github"]
1. Nf3 Nf6 2. c4 g6 3. a4 a5
*/

Extract position after certain move:

$pgn = new Onspli\Chess\PGN('1.Nf3 Nf6 2.c4 g6');
echo($pgn->get_current_fen());
// rnbqkb1r/pppppp1p/5np1/8/2P5/5N2/PP1PPPPP/RNBQKB1R w KQkq - 0 3
echo($pgn->get_initial_fen());
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
echo($pgn->get_fen_after_halfmove(0));
// rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
echo($pgn->get_fen_after_halfmove(2));
// rnbqkb1r/pppppppp/5n2/8/8/5N2/PPPPPPPP/RNBQKB1R w KQkq - 2 2
echo($pgn->get_fen_after_halfmove(Onspli\Chess\PGN::get_halfmove_number(1, 'b')));
// rnbqkb1r/pppppppp/5n2/8/8/5N2/PPPPPPPP/RNBQKB1R w KQkq - 2 2

FEN is returned as string by default. Passing parameter $as_object = true makes it FEN object:

$pgn = new Onspli\Chess\PGN('1.Nf3 Nf6 2.c4 g6');
echo($pgn->get_current_fen(true)->preview());
/*
rnbqkb.r
pppppp.p
.....np.
........
..P.....
.....N..
PP.PPPPP
RNBQKB.R
*/
echo($pgn->get_fen_after_halfmove(2, true)->preview());
/*
rnbqkb.r
pppppppp
.....n..
........
........
.....N..
PPPPPPPP
RNBQKB.R
*/

PGN with custom initial position:

$pgn = new Onspli\Chess\PGN('[FEN "rnbqkb1r/pppp1ppp/5n2/4p3/2P1P3/5N2/PP1P1PPP/RNBQKB1R b KQkq - 0 3"] 3... Nc6 4. Qb3');
echo($pgn->get_initial_fen());
// rnbqkb1r/pppp1ppp/5n2/4p3/2P1P3/5N2/PP1P1PPP/RNBQKB1R b KQkq - 0 3
echo($pgn->get_initial_halfmove_number());
// 6
echo($pgn->get_halfmove(6));
// Nc6