PHP: multi-process socket TCP per acquisire dati dal GPS Tracker GPS-102 compatibile OpenGTS

multi-process php socket

multi-process php socket

Nei precedenti articoli “PHP: un socket TCP per acquisire dati dal GPS Tracker GPS-102 compatibile OpenGTS” (prima, seconda e terza parte), ho descritto come implementare un socket TCP in PHP per acquisire i dati GPS da un tracker di tipo TK-102 (e compatibili).

Lo script però era progettato per singolo processo, cioè non poteva servire più di una connessione alla volta e non era dunque in grado di gestire connessioni concorrenti.

E’ invece molto utile che un socket server di questo tipo sia in grado di gestire connessioni concorrenti in modo da prendere in carico più GPS tracker contemporaneamente. Fortunatamente il linguaggio PHP supporta la programmazione multi-processo attraverso l’utilizzo di fork(). In questo modo il processo padre chiamato in causa da una nuova connessione genera un processo figlio che condivide le variabili e le risorse e rimane libero di accettare nuove connessioni.

Ho approfittato dell’occasione di riscrivere il codice in modalità multiprocesso anche per aggiornare la connessione al database server MySQL utilizzando l’estensione mysqli al posto della originale mysql ormai deprecata nel PHP 5.5.x. Infine ho semplificato il codice togliendo il controllo sulla soglia di movimento e correggendo alcuni bug.

Un buon esempio di scrittura di socket multi-processo è consultabile qui, e da questo esempio ho adottato l’intelaiatura del codice.

Ecco il codice completo:

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#!/usr/bin/php -q
<?php
/***********************************************************************
* mstracker is developed with GPL Licence 2.0
*
* GPL License: http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
*
* Developed by : Mario Spada from an idea of Cyril Feraudet 
* at: https://github.com/feraudet/tracker/blob/master/trackerTK102
* 
* Web: http://www.spadamar.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
*    For information : spadamar@spadamar.com
***********************************************************************/
 
/***********************************************************************
  * SETTINGS
  *********************************************************************/
// Constants -----------------------------------------------------------
/* HOST                                                               */
define("IP_ADDR",'0.0.0.0'); // "0.0.0.0" = listen all ip
define("TCP_PORT",5050); // 5050
define("DEBUG", true);
/* TRACKER                                                            */
define("POLL_TIME",60); // SET POLL TIME 20,30,60,300,600 default:60 secs
define("SPEED_CONV",1.852); //From NM mile to Km
define("DFLT_MSG","tracker");
/* DATABASE                                                           */
define("DBHOST","127.0.0.1");
define("DBUSER","your_db_user");
define("DBPASS","your_db_password");
define("DBNAME","gts");
/* OTHER SETTINGS                                                     */
define("OPENGTS",true);
define("USE_SERVER_TIME",true);
// Variables -----------------------------------------------------------
$__server_listening = true;
$sendPollTime = false;
// ---------------------------------------------------------------------
/***********************************************************************
  * INIT
  *********************************************************************/
error_reporting(E_ALL);
set_time_limit(0);
ob_implicit_flush();
declare(ticks = 1);
 
$pid = become_daemon();
write_pid($pid);
 
/* nobody/nogroup, change to your host's uid/gid of the non-priv user */
change_identity(65534, 65534);
 
/* handle signals */
pcntl_signal(SIGTERM, 'sig_handler');
pcntl_signal(SIGINT, 'sig_handler');
pcntl_signal(SIGCHLD, 'sig_handler');
 
/* set default timezone */
date_default_timezone_set('Europe/Rome');
/***********************************************************************
  * Listens for requests and forks on each connection
  *********************************************************************/
server_loop();
/***********************************************************************
  * Change the identity to a non-priv user
  * @param int $uid linux user id
  * @param int $gid linux group id
  *********************************************************************/
function change_identity( $uid, $gid ) {
    if( !posix_setgid( $gid ) ) {
        $msg = "Unable to setgid to " . $gid . "!";
		writeLog($msg,true);
		exit;
    }
    if( !posix_setuid( $uid ) ) {
        $msg = "Unable to setuid to " . $uid . "!";
		writeLog($msg,true);
		exit;
    }
}
/***********************************************************************
  * Creates a server socket and listens for incoming client connections
  * @param string $address The address to listen on
  * @param int $port The port to listen on
  *********************************************************************/
function server_loop() {
    GLOBAL $__server_listening;
    if(($sock = socket_create(AF_INET, SOCK_STREAM, 0)) < 0) {
        $msg = "failed to create socket: ".socket_strerror($sock);
        writeLog($msg,true);
        exit;
    }
    if(($ret = socket_bind($sock, IP_ADDR, TCP_PORT)) < 0) {
        $msg = "failed to bind socket: ".socket_strerror($ret);
        writeLog($msg,true);
        exit;
    }
    if( ( $ret = socket_listen( $sock, 0 ) ) < 0 ) {
        $msg = "failed to listen to socket: ".socket_strerror($ret);
        writeLog($msg,true);
        exit;
    }
    socket_set_nonblock($sock);
	writeLog("waiting for clients to connect");
    while ($__server_listening) {
        $connection = @socket_accept($sock);
        if ($connection === false) {
            usleep(100);
        } elseif ($connection > 0) {
            handle_client($sock, $connection);
        } else {
			$msg = "error: ".socket_strerror($connection);
            writeLog($msg,true);
        }
    }
}
/***********************************************************************
  * Signal handler
  * @param int $sig The signal number
  *********************************************************************/
function sig_handler($sig) {
    switch($sig) {
        case SIGTERM:
        case SIGINT:
            exit;
        break;
        case SIGCHLD:
            pcntl_waitpid(-1, $status);
        break;
    }
}
/***********************************************************************
  * Handle a new client connection
  * @param $ssock resource
  * @param $csock resource
  *********************************************************************/
function handle_client($ssock, $csock) {
    GLOBAL $__server_listening;
    $pid = pcntl_fork();
    if ($pid == -1) {		
		writeLog("fork failure!",true);
		exit;        
    } elseif ($pid == 0) {
        /* child process */
		writeLog("CONNECT");
        $__server_listening = false;
        socket_close($ssock);
        interact($csock);
        socket_close($csock);
        writeLog("SOCKET CLOSE");
    } else {
        socket_close($csock);
        writeLog("SOCKET CLOSE");
    }
}
/***********************************************************************
  * Talk to client
  * @param $socket resource
  *********************************************************************/
function interact($socket) {
	global $sendPollTime;
	try {	
		$buf = "";
		socket_recv($socket, $buf, 2048, 0);
		writeLog("RECEIVED: ".$buf);
		$outData = array();
		$rec = trim($buf); // clean up input string
		$multiplePos = (substr($buf, 0, 2) == "##") ? false : true;
		$actualIMEI = (!$multiplePos) ? substr($buf, 8, 15) : substr($buf, 5, 15);  // returns IMEI
		if (!$multiplePos){
			$output = "LOAD". "\n";
			writeLog("SEND: LOAD");
			// Send intructions
			socket_write($socket, $output, strlen($output));
			if (FALSE === ($buf = socket_read($socket, 2048))) {
				throw new Exception("socket_read() failed: " . socket_strerror(socket_last_error($socket)));
			}				
			$buf = trim($buf);
			writeLog("RECEIVED: ".$buf);
			if (empty($buf)){
				 throw new Exception("Received: nothing, disconnect");
			}
			if (($sendPollTime === false)) {
				$output = "ON". "\n";
				writeLog("SEND: ON");
				socket_write($socket, $output, strlen($output));
				$output = "**,imei:".$actualIMEI."," . pollTimeString(POLL_TIME)."\n";
				socket_write($socket, $output, strlen($output));
				writeLog("SEND: ".$output);
				if (FALSE === ($buf = socket_read($socket, 2048))) {
					$sendPollTime = false;
					throw new Exception("socket_read() failed: " . socket_strerror(socket_last_error($msgsock)));
				}
				$buf = empty($buf) ? "NO DATA" : trim($buf);
				$sendPollTime = true;
			}
		}	
		$outData = explode ( "," , $buf );
		if(count($outData)>=5){
			$outDecodedData = decodeData($outData);
			if ($outDecodedData['DATA_FL'] == "F" || $outDecodedData['MSG'] !== DFLT_MSG){
                writeLog(print_r($outDecodedData,true));
				if (OPENGTS) {
					$res = updatePosOpenGTS($outDecodedData);
				} else {
					$res = updatePosGpsd($outDecodedData);
				}                
			}
		}
	} catch (Exception $e) {
		writeLog(" ".$e->getMessage(),true);
	}
 
}
/***********************************************************************
  * Become a daemon by forking and closing the parent
  *********************************************************************/
function become_daemon() {
    $pid = pcntl_fork();
    if ($pid == -1) {
        /* fork failed */
        echo "fork failure!\n";
        exit();
    } elseif ($pid) {
        /* close the parent */
        exit();
    } else {
        /* child becomes our daemon */
        posix_setsid();
        chdir('/');
        umask(0);
        return posix_getpid();
    }
}
/***********************************************************************
  * Write pid
  * @param int $pid Process ID
  *********************************************************************/
function write_pid($pid) {
	$fn = preg_replace('/\.php$/', '', __FILE__);
	$fn .= "_pid"; 
	$fp = fopen($fn, 'w');
	fwrite($fp, $pid);
	fclose($fp);	
} 
/***********************************************************************
  * Write log
  * @param string $msg Text to write
  * @param bool $is_error If is error is always written
  *********************************************************************/
function writeLog($msg,$is_error=false) {
	$msg = now()." ".$msg."\n";
	if($is_error){
		echo $msg;
	} else {
		if(DEBUG)
			echo $msg;
	}
	return true;
}
/***********************************************************************
  * Return date and time
  * *******************************************************************/
function now($secs=0){
	return date("Y-m-d H:i:s", time()+$secs);
}
/***********************************************************************
  * Check if is a valid date
  * @param $str string Date string
  * *******************************************************************/
function is_valid_date($str){
	$str = str_replace("-"," ",$str);
	$str = str_replace(":"," ",$str);
	$arrDate = explode(" ",$str);
	foreach($arrDate as $val){
		if (!is_numeric($val)){
			return false;
		}
	}
	$res = checkdate(intval($arrDate[1]),intval($arrDate[2]),intval($arrDate[0]));
	$res = $res && ($arrDate[3] >=0 && $arrDate[3] <=24);
	$res = $res && ($arrDate[4] >=0 && $arrDate[4] <=59);
	return $res;
}
/***********************************************************************
  * Compose time interval string
  * @param $sec int seconds
  * *******************************************************************/
function pollTimeString($secs){
	$secs = intval($secs);
	switch ($secs) {
		case 20:
			$res = "20s";
			break;
		case 30:
			$res = "30s";
			break;
		case 60:
			$res = "01m";
			break;
		case 300:
			$res = "05m";
			break;
		case 600:
			$res = "10m";
			break;
		default:
			$res = "01m";
	}
	return "C,".$res;
}
/***********************************************************************
  * Decode data array
  * @param $arr array Data array
  * *******************************************************************/
function decodeData($arr){
/* *********************************************************************
*   0 = imei:000000000000000	[imei]
*   1 = tracker					[Msg: help me / low battery / stockade /
* 											dt /move / speed / tracker]
*   2 = 0809231929				[acquisition time: YYMMDDhhmm +8GMT cn]
*   3 = 13554900601				[adminphone?]
*   4 = F						[Data: F - full / L - low]
*   5 = 112909.397				[Time (HHMMSS.SSS)]
*   6 = A						[A = available?]
*   7 = 2234.4669				[Latitude (DDMM.MMMM)]
*   8 = N						[Lat direction: N / S]
*   9 = 11354.3287				[Longitude (DDDMM.MMMM)]
*  10 = E						[Lon direction: E / O]
*  11 = 0.11					[speed Mph]
***********************************************************************/
	$out = array();
	$out['IMEI'] = substr($arr[0], 5, 15);
	$out['MSG'] = trim($arr[1]);
	$out['ACQUISITION_TIME'] = substr($arr[2], 0, 2)."-".
						substr($arr[2], 2, 2)."-".substr($arr[2], 4, 2).
						" ".substr($arr[2],6,2).":".substr($arr[2],8,2);
	$out['ADMINPHONE'] = trim($arr[3]);
	$out['DATA_FL'] = trim($arr[4]);
	 if ($out['DATA_FL'] === "F"){
		 $out['TIME'] = substr($arr[5], 0, 2).":" . substr($arr[5], 2, 2).":" . substr($arr[5], 4, 2); // skip milliseconds...
		 $out['AVAILABLE'] = $arr[6]==="A" ? 1 : 0;
		 $out['LAT'] = floatval(substr($arr[7], 0, 2)) +
					   floatval(substr($arr[7], 2, 7)) / 60;
		 $out['LAT'] = $arr[8]==="N" ? $out['LAT'] : -$out['LAT'];
		 $out['LON'] = floatval(substr($arr[9], 0, 3))  +
					   floatval(substr($arr[9], 3, 7)) / 60;
		 $out['LON'] = $arr[10]==="E" ? $out['LON'] : -$out['LON'];
		 $out['SPEED'] = floatval($arr[11]) * SPEED_CONV;
	}
	else {
		 $out['TIME'] = "00:00:00";
		 $out['AVAILABLE'] = 0;
		 $out['LAT'] = (float) 0;
		 $out['LON'] = (float) 0;
		 $out['SPEED'] = (float) 0;
	}
	return $out;
}
/***********************************************************************
  * Update position on OpenGTS DB
  * @param $data array Data array 
  * *******************************************************************/
function updatePosOpenGTS($data){
	$res = false;
	if (false !== ($cn = db_connect())) {
		try {
			//escape data
			clean_array($cn,$data);		
			$sql = "SELECT imeiNumber FROM Device WHERE imeiNumber = '{$data['IMEI']}' AND isActive;";
			writeLog($sql);
			if ($result = $cn->query($sql)) {
				if ($result->num_rows == 1) {
					$result->close();
					$rawData = implode(",",$data);
					if (USE_SERVER_TIME) {
						$acq_time = now(-POLL_TIME);
					} else {
						$date = new DateTime($data['ACQUISITION_TIME']);
						$data['ACQUISITION_TIME'] = $date->format('Y-m-d H:i:s');
						$exactDate = substr($data['ACQUISITION_TIME'],0,10)." ".$data['TIME'];
						$acq_time = is_valid_date($exactDate) ? $exactDate : now(-POLL_TIME);
					}				
$sql = <<<STR
START TRANSACTION;
	UPDATE Device SET lastValidLatitude = {$data['LAT']}, lastValidLongitude = {$data['LON']}, lastGPSTimestamp = UNIX_TIMESTAMP('{$acq_time}'), lastUpdateTime = UNIX_TIMESTAMP(NOW()) WHERE imeiNumber = RIGHT(CONCAT('000000000000000', '{$data['IMEI']}'), 15);
	SELECT @accountID := accountID, @deviceID := deviceID FROM Device WHERE imeiNumber = RIGHT(CONCAT('000000000000000', '{$data['IMEI']}'), 15);
	INSERT INTO EventData (accountID, deviceID, timestamp, statusCode, latitude, longitude, speedKPH, heading, altitude, rawData, creationTime, address)
	VALUES (@accountID, @deviceID, UNIX_TIMESTAMP('{$acq_time}'), 0, {$data['LAT']}, {$data['LON']}, {$data['SPEED']}, 0, 0, '{$rawData}', UNIX_TIMESTAMP(NOW()), '');
COMMIT;
STR;
					writeLog($sql);
					$res = $cn->multi_query($sql);
					while ($cn->next_result()) {;} // flush multi_queries
				} else {
					writeLog("Invalid IMEI or device is not active!");
					$result->close();
				}
			}			     
		} catch (Exception $e) {
			writeLog(" ".$e->getMessage(),true);
		}
		db_close($cn);
	}
	return $res;
}
/***********************************************************************
  * Update position on Gpsd DB 
  * @param $data array Data array
  * *******************************************************************/
function updatePosGpsd($data) {
	$res = false;
	if (false !== ($cn = db_connect())) {
		try {
			//escape data
			clean_array($cn,$data);
			$sql = "SELECT imeiNumber FROM devices WHERE imeiNumber = '{$data['IMEI']}';";
			writeLog($sql);
			if ($result = $cn->query($sql)) {			
				if ($result->num_rows == 1) {
					if (USE_SERVER_TIME) {
						$acq_time = now(-POLL_TIME);
					} else {
						$date = new DateTime($data['ACQUISITION_TIME']);						
						$data['ACQUISITION_TIME'] = $date->format('Y-m-d H:i:s');
						$exactDate = substr($data['ACQUISITION_TIME'],0,10)." ".$data['TIME'];
						$acq_time = is_valid_date($exactDate) ? $exactDate : now(-POLL_TIME);
					}
$sql = <<<STR
START TRANSACTION;
	SELECT @deviceID := devices.id FROM devices WHERE imeiNumber = '{$data['IMEI']}';
	INSERT INTO positions (msg,timestamp,acq_time,track_time,is_valid,latitude,longitude,speedKPH,course,device_id) 
	VALUES ('{$data['MSG']}',UNIX_TIMESTAMP(NOW()),'{$acq_time}','{$data['TIME']}',{$data['AVAILABLE']},{$data['LAT']},{$data['LON']},{$data['SPEED']},0,@deviceID);
COMMIT;
STR;
					writeLog($sql);
					$res = $cn->multi_query($sql);
					while ($cn->next_result()) {;} // flush multi_queries
				} else {
					writeLog("Invalid IMEI!");
					$result->close();									
				}
			}		
		} catch (Exception $e) {
			writeLog(" ".$e->getMessage(),true);
		}				
		db_close($cn);
	}
	return $res;
}
/***********************************************************************
  * Clean data array 
  * *******************************************************************/
function clean_array($cn,&$data) {
	foreach ($data as $key => $val) {
		$data[$key] = mysqli_real_escape_string($cn,$val);
	}
} 
/***********************************************************************
  * Connect to DB 
  * *******************************************************************/
function db_connect() {
	$link = mysqli_connect(DBHOST, DBUSER, DBPASS, DBNAME);
	if (!$link) {
		writeLog( "Error: Unable to connect to MySQL.",true);
		return false;
	}
	return	$link;
}
/***********************************************************************
  * Disconnect from DB
  * @param $link resource mysqli connection 
  * *******************************************************************/
function db_close($link) {
	return mysqli_close($link);
}
?>

Per i settaggi vale quanto riportato nell’articolo: PHP: un socket TCP per acquisire dati dal GPS Tracker GPS-102 compatibile OpenGTS (seconda parte)

Riferimenti:

 

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