使用__get或类似方法访问Array类型的类成员变量

Question

Previously a class which I'm now rebuilding had a member variable $settings which was an array of settings, strangely enough.

class MyClass {
    public $settings = array();

    public function __construct() {
        if( empty( $this->settings ) ) {
            $this->settings = require( 'settings.php' ); // e.g. return array('setting1'=>4);
        }
    }
}

These settings were accessed by $object->settings['keyname'];

The means by which these keys are accessed has been moved into a method now. However, the application itself is riddled with calls to $object->settings['keyname']. I was wondering is there a way which I can catch any calls to the $settings member variable and return it using the new function.

I've looked at __get($name) but $name only contains settings rather than the array key which I need. What I'd need to pass would be the keyname to the my $object->get() method.

The reason I want to do this is so that I can trigger errors in a log file showing me where the deprecated calls to $object->settings[] are without breaking the application. Obviously setting $setting to private would give me lots of fatal errors and I could work through but there are multiple developers working on this codebase which I'd prefer not to break. If I could implement this as a temporary solution it'd help.

I realise there are repositories etc which we could use so that I could work on it separately and check it in afterwards but I'm looking for a quick, temporary solution as we're porting our codebase to Git soonish.

Answer 1

Totally possible:

<?php
class Logger {
    public function log( $name, $backtrace ) {
        /**
         * $name is the name of the array index that was called on
         * MyClass->settings( ). $backtrace contains an array in which
         * you can find and determine which file has accessed that index,
         * and on which line.
         */
        $last = array_shift( $backtrace );
        $message = sprintf( "Setting '%s' was called by file '%s' on line %d",
            $name,
            $last['file'],
            $last['line']
        );

        echo $message;  

    }
}

class MyClass {
    protected $settings;

    public function __construct( ) {
        $this->settings = new Settings( new Logger( ), array( 'foo' => 'bar' ) );
    }

    public function __get( $name ) {
        if( $name === 'settings' ) {
            return $this->settings;
        }
    }
}

class Settings extends ArrayObject {
    protected $logger;
    protected $settings;
    public function __construct( Logger $logger, array $settings ) {
        $this->logger = $logger;
        parent::__construct( $settings );
    }

    public function offsetGet( $name ) {
        $backtrace = debug_backtrace( );
        $this->logger->log( $name, $backtrace );
        return parent::offsetGet( $name );
    }
}

$myClass = new MyClass( );
echo $myClass->settings['foo'] . "
";

Sure, it's hackish, and you probably don't want to keep this in your codebase, but for logging deprecated uses, it might be extremely helpful. Just log for a set period of time, and then replace the $this->settings = new Settings( ) with $this->settings = array( ).

By the way, the output of that exact code is the following:

berry@berry-pc:~/Desktop% php foo.php
Setting 'foo' was called by file '/home/berry/Desktop/foo.php' on line 53
bar