Accessing PHP variable from static function

Question

I am getting error in below code, cause am not able to access $log in static function Log which gets initialized in _construct.

class Logger extends Singleton{

    protected function __construct() {
        if(!class_exists("Log")) {
            include '/usr/php/Log.php';
        }
        $MONITORING_LOGFILE = "/var/log/Monitoring.log";

        ini_set('error_log', 'syslog');
        openlog($MONITORING_LOGFILE, LOG_NDELAY, LOG_LOCAL0);
        $log = Log::singleton('syslog', LOG_LOCAL0, $MONITORING_LOGFILE, array('lineFormat' => ' %{message}'), PEAR_LOG_DEBUG);
    }


    public static function Log($message){
        $log->err($message);
    }
}

Ok, I modified the above code

class Logger extends Singleton{
    private $log;

    protected function __construct() {
        if(!class_exists("Log")) {
            include '/usr/php/Log.php';
        }
        $MONITORING_LOGFILE = "/var/log/Monitoring.log";

        ini_set('error_log', 'syslog');
        openlog($MONITORING_LOGFILE, LOG_NDELAY, LOG_LOCAL0);
        $this->log = Log::singleton('syslog', LOG_LOCAL0, $MONITORING_LOGFILE, array('lineFormat' => ' %{message}'), PEAR_LOG_DEBUG);
    }


    public function Log($message){
        $this->log->err($message);
    }
}

and now its working fine .... just want to confirm if initializng like this is ok in Singleton pattern?

The constructor is not called if you just invoke Logger::Log statically. You need to retrieve the singleton instance of Logger from inside Log(). And you need to save $log in the constructor, or it's just a local variable that will get lost. — LSerni
– LSerni, Commented Feb 2, 2015 at 7:02

Kheshav Sewnundun · Accepted Answer · 2015-02-02 08:18:27Z

1

To be able to access the $log variable trough a static function you need to have a reference of it:

class Logger extends Singleton{
    private static $log; //static instance of Log::singleton
    protected function __construct() {
        if(!class_exists("Log")) {
            include '/usr/php/Log.php';
        }
        $MONITORING_LOGFILE = "/var/log/Monitoring.log";

        ini_set('error_log', 'syslog');
        openlog($MONITORING_LOGFILE, LOG_NDELAY, LOG_LOCAL0);
        self::$log = Log::singleton('syslog', LOG_LOCAL0, $MONITORING_LOGFILE, array('lineFormat' => ' %{message}'), PEAR_LOG_DEBUG);
    }

    //static method
    public static function Log($message){
        self::$log->err($message);
    }
}

To create your instance of the class Logger and access the static Log function you can do the following:

$mylog = new Logger();
$mylog::Log("Your text here");

answered Feb 2, 2015 at 8:18

Kheshav Sewnundun

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1 Comment

Sonal Over a year ago

Thanks Kheshav. I cannot create an object of Logger as its extending Singleton pattern. I accessed it as Logger::getInstance()->Log("Message"); The above code works fine.

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