How I (ab)used php with the help of reactphp

PHP is one of the most accessible and commonly used languages in computer programming. It’s used for building websites, web applications, micro services and loads of other stuff. Normally we would not use it to control hardware. But let that be the showcase of this talk. I’ll show you how I ab(used) PHP to control hardware used during track and field competitions. It involves LED-panels, serial-to-ethernet-­convertors and the use of reactphp, an event-driven non-blocking I/O library.

Transcript

1. how I (ab)used PHP with the help of reactphp
2. Stijn Vannieuwenhuyse developer at teamleader
3. Stijn Vannieuwenhuyse track and field timer
4. Track & Field its all about precise numbers
5. Team Arctic v.z.w. team for athletics' results communication, timing, information and coordination
6. Track & Field its all about precise numbers
7. What's wrong with it? Why change?
8. Problem 1 How to integrate?
9. FT01<TR><TD> Long jump men </TD></TR> <TR> <TD CLASS="DAMP"><span class="teamflag"></span></TD> <TD CLASS="name">Lambert Romain</TD> <TD CLASS="team">DAMP</TD> </TR> <TR> <TD CLASS="attempt">A6</TD> <TD CLASS="result"> </TD> <TD CLASS="rank">Rank:&nbsp;1</TD> </TR>
10. RS232
11. Problem 2 How to connect?
12. PHP developer
13. reactphp event-driven, non-blocking I/O with PHP
14. public function run() { $this->running = true; while ($this->running) { $this->nextTickQueue->tick(); $this->futureTickQueue->tick(); $this->timers->tick(); if (!$this->running || !$this->nextTickQueue->isEmpty() || !$this->futureTickQueue->isEmpty()) { $timeout = 0; } elseif ($scheduledAt = $this->timers->getFirst()) { $timeout = $scheduledAt - $this->timers->getTime(); if ($timeout < 0) { $timeout = 0; } else { $timeout *= self::MICROSECONDS_PER_SECOND; } } elseif ($this->readStreams || $this->writeStreams) { $timeout = null; } else { break; } $this->waitForStreamActivity($timeout); } } ^ infinite loop for as long as their is stuff to do ^ callbacks queued ^ ticks - next : execute in same loop - future execute in next loop
15. composer require react/socket
16. $loop = Factory::create(); $connector = new TcpConnector($loop); $connector->create('192.168.1.93', 6000)->then( function(Stream $stream) { echo "connected", PHP_EOL; } ); $loop->run();
17. composer require react/socket-client
18. Problem 3 How to communicate?
19. C\x0d
20. TFF000000a2000700100030a012345678910\x0d
21. TRRGGBBXXXXYYYYLLLLHHHHFDDDDDDDDDD\x0d T: command name RRGGBB: hex color value XXXX: x-position in hex, starting from left YYYY: y-position in hex, starting from top LLLL: length of the text in hex HHHH: heigth of the text in hex F: font-type D: data \x0d: end marker
22. Domain Driven Design make the implicit explicit
23. interface Instruction { /** * @return string */ public function toData(); }
24. class Clear implements Instruction { public function toData() { return "C\x0d"; } }
25. class Text implements Instruction { private $data; private $x; private $y; private $height; private $length; private $colorCode; private $font; public function __construct($data, $x, $y, $height, $length, $colorCode, $font) { $this->data = $data; $this->x = $x; $this->y = $y; $this->height = $height; $this->length = $length; $this->colorCode = $colorCode; $this->font = $font; } public function toData() { return sprintf( "T%s%04X%04X%04X%04X%s%s\x0d", $this->getColor(), //returns hex string of red, green or yellow $this->x, $this->y, $this->length, $this->height, $this->font, $this->data ); } }
26. B00100028004700af0f0f0f0fff0fff0f\x0d
27. BXXXXYYYYLLLLHHHHDDDDDDDDDDD\x0d B: command name XXXX: x-position in hex, starting from left YYYY: y-position in hex, starting from top LLLL: length of the text in hex HHHH: heigth of the text in hex D: data \x0d: end marker
28. Domain Specific Language
29. . . . . . . . . . . . Y Y Y Y Y Y Y . . . . . . . . . . . . . . . . . . . Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y R R R R R R R R R R R Y . . . . . Y G G G G G G G G G G G G G G G G G G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . . . . Y . Y Y Y . Y . . . . . G . . . . . G . . . . . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . R . R R R . Y . . . Y . Y . G . G . G . G G G . G . G G G . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . R . . . R . Y . Y Y Y . Y . G . G . G . G . . . G . G . . . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . R . R R R . Y . . . Y . Y . G G G . G . G G G . G . G G G . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . R . R . . . Y . Y Y Y . Y . . . G . G . . . G . G . G . G . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . R . R R R . Y . . . . . Y . . . G . G . G G G . G . G G G . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R . . . . . Y . . . . . Y . . . . . G . . . . . G . . . . . G . Y . . . . . . . . . . . . . . . . . . . . . . . . . . Y Y Y Y Y Y Y Y Y Y Y Y . . . . . Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . . . . . . . . . . . . . . . . . . .
30. Value Objects
31. new Bitmap() new BitmapBlock() new BitmapLine()
32. Dot Matrix Fonts
33. final class AdvancedDotDigital extends Font { protected static $chars = [ "0" => "01111110\n11111111\n11000011\n11000011\n11000011\n11000011\n11000011\n11000011\n11000011\n11000011\n11111111\n01111110", "1" => "00011000\n00111000\n01111000\n11011000\n00011000\n00011000\n00011000\n00011000\n00011000\n00011000\n11111111\n11111111", "2" => "01111110\n11111111\n11000011\n00000011\n00000011\n01111111\n11111110\n11000000\n11000000\n11000000\n11111111\n11111111", "3" => "01111110\n11111111\n11000011\n00000011\n00000011\n00111110\n00111110\n00000011\n00000011\n11000011\n11111111\n01111110", "4" => "11000011\n11000011\n11000011\n11000011\n11000011\n11000011\n11111111\n11111111\n00000011\n00000011\n00000011\n00000011", "5" => "11111111\n11111111\n11000000\n11000000\n11111110\n11111111\n00000011\n00000011\n00000011\n11000011\n11111111\n01111110", "6" => "01111110\n11111111\n11000011\n11000000\n11111110\n11111111\n11000011\n11000011\n11000011\n11000011\n11111111\n01111110", "7" => "11111111\n11111111\n11000110\n00000110\n00001100\n00001100\n00011000\n00011000\n00110000\n00110000\n00110000\n00110000", "8" => "01111110\n11111111\n11000011\n11000011\n11000011\n01111110\n01111110\n11000011\n11000011\n11000011\n11111111\n01111110", "9" => "01111110\n11111111\n11000011\n11000011\n11000011\n11000011\n11111111\n01111111\n00000011\n11000011\n11111111\n01111110", "m" => "0000000000\n0000000000\n0000000000\n0000000000\n0000000000\n1111101110\n1111111111\n1100110011\n1100110011\n1100110011\n1100110011\n1100110011\n1100110011", "X" => "1100000000011\n0110000000110\n0011000001100\n0001100011000\n0000110110000\n0000011100000\n0000011100000\n0000110110000\n0001100011000\n0011000001100\n0110000000110\n1100000000011", "O" => "0000111110000\n0011111111100\n0111000001110\n0110000000110\n1100000000011\n1100000000011\n1100000000011\n1100000000011\n0110000000110\n0111000001110\n0011111111100\n0000111110000", ":" => "0000\n0000\n0110\n0110\n0000\n0000\n0000\n0000\n0110\n0110\n0000\n0000", "-" => "0000000000000\n0000000000000\n0000000000000\n0000000000000\n0000000000000\n0011111111100\n0011111111100\n0000000000000\n0000000000000\n0000000000000\n0000000000000\n0000000000000", ]; }
34. Problem 4 How to get updates?
35. inotify
36. inotify_init() : filedescriptor inotify_add_watch($fd, $path, $mask) : watchDescriptorId inotify_rm_watch($fd, $wdId) inotify_read($fd) : event[] IN_MODIFY IN_CREATE IN_ALL_EVENTS IN_OPEN ...
37. class Watcher { public function __construct($dir, LoopInterface $loop) { $fd = inotify_init(); stream_set_blocking(fd, 0); inotify_add_watch($fd, $dir, IN_MODIFY); $loop->addReadStream($fd, function($fd) { foreach(inotify_read($fd) as $events) { //process change } } ) } }
38. Problem 5 How to combine I/O?
39. interface Layout { /** * @return Instruction[] */ public function toInstructions(); }
40. class NextAthlete implements Layout { private $name; private $team; private $attempt; private $place = null; private $height = null; public function __construct($name, $team, $attempt, $place = null, $height = null) { $this->name = $name; $this->team = $team; $this->attempt = $attempt; $this->place = $place; $this->height = $height; } /** * @return Instruction[] */ public function toInstructions() { $instructions = []; $name = (new Text(strtoupper($this->name), RingMatrix::class, "Y"))->toBitmap(); $instructions[] = new Bitmap(0, 0, $name); $team = (new Text(strtoupper($this->team), SquareDotDigital::class, "R"))->toBitmap(); $instructions[] = new Bitmap(64 - $team->getLength(), 11, $team); //some other conversion from data to instructions return $instructions; } }
41. Problem 6 How to send own layouts?
42. PHP TCP server
43. $loop = Factory::create(); $server = new Server($loop); $server->on('connection', function (Connection $connection) { echo sprintf("%s came online\n", $connection->getRemoteAddress()); $connection->on('close', function(Stream $stream) use ($connection) { echo sprintf("%s went offline\n", $connection->getRemoteAddress()); }); }); $server->listen('6000', '0.0.0.0'); $loop->run();
44. Command pattern
45. { "commandName":"Nortuni.FieldScoreboardManager.Commands.ShowLayout", "payload": { "scoreBoardId": "LED01", "layoutName": "TwoLines", "data": { "line1": "TEAM", "line2": "ARCTIC" } } }
46. $loop = Factory::create(); $deviceServer = new Server($loop); $commandServer = new Server($loop); $deviceServer->on('connection', function (Connection $connection) { //do some stuff }); $commandServer->on('connection', function (Connection $connection) { $connection->on('data', function() { //parse json to command //dispatch command }) }); $deviceServer->listen('6000', '0.0.0.0'); $commandServer->listen('6001', '0.0.0.0'); $loop->run();
47. Problem 7 How to open up control?
48. $socketServer = new Server($loop); $webserver = new React\Http\Server($socketServer); $webserver->on('request', function ($request, $response) { //just like a normal controller method //$response is a writable stream }); $socket->listen(8080);
49. Problem 8 How to get current state?
50. websockets
51. composer require cboden/ratchet
52. class WebSocketConnector implements MessageComponentInterface { private $clients; public function __construct() { $this->clients = new SplObjectStorage; } public function onOpen(ConnectionInterface $connection) { $this->clients->attach($conn); } public function onClose(ConnectionInterface $connection) { $this->clients->detach($connection); } public function onError(ConnectionInterface $connection, \Exception $e) { $connection->close(); } public function onMessage(ConnectionInterface $from, $msg) { //process data } public function sendToClients($data) { foreach($this->clients as $client) { $client->send($data); } } }
53. $socketServer = new Ratchet\App('192.168.6.161', 8080, '0.0.0.0', $loop); $socketServer->route('/field', new WebSocketConnector(), ['*']);
54. var connection = null; var connect = function() { connection = new WebSocket('ws://192.168.6.10:8080/field'); connection.onopen = function() { //log or ... }; connection.onmessage = function(message) { //process message.data } connection.onclose = function() { connection = null; setTimeout(connect, 1000); }; } var dispatch = function(data) { if(connection && connection.readyState == WebSocket.OPEN) { connection.send(data); } };
55. Problem 9 How to automate?
56. { "commandName":"Nortuni.FieldScoreboardManager.Commands.ShowSlideshow", "payload": { "scoreBoardId":"LED01", "interval":"20", "screens":[ { "layoutName":"MeetingName", "data": { "line1":"PHPGENT", "line2":"MEETUP", "line3":"", "line4":"WELCOME" } }, { "layoutName":"MeetingName", "data": { "line1":"", "line2":"TEAMLEADER", "line3":"CRM", "line4":"" } } ] } }
57. timers
58. $this->timer = $this->loop->addPeriodicTimer($interval, function() { $this->showNextSlide(); });
59. it works for now
60. my experiences
61. async programming in PHP is possible
62. php is stable enough for long running processes
63. reactphp is a mature and rich library
64. I use reactphp in production
65. I shouldn't use php for this
66. Questions?
67. Stijn Vannieuwenhuyse @stijnvnh