How to retrieve method of a class in anonymous function?

Question

How to retrieve method of a class in anonymous function? Does another opportunity exist to solve this?

Task: I need to upload a image from remote path and change it to local path.

Code:

    $pattern = '/<img src=(.*?jpg|gif|png).*?>/m';

    $uploadImage = function($image)
    {
        $this->uploadPictures();
    };

    function image_replace($matches) use ($uploadImage)
    {
        // как обычно: $matches[0] -  полное вхождение шаблона
        // $matches[1] - вхождение первой подмаски,
        // заключенной в круглые скобки, и так далее...
        $uploadImage($matches[1]);

        return $matches[1].($matches[2]+1);
    }

    preg_replace_callback(
        $pattern,
        "image_replace",
        $text);

@sinaneker Comment is not relevant to the problem. It just explains what $match contains. — Leri
– Leri, Commented Jul 5, 2013 at 9:40
@korvinko It seems that $this is used out of the scope. Can you update how that class looks? — Leri
– Leri, Commented Jul 5, 2013 at 9:41

deceze · Accepted Answer · 2013-07-05 09:47:05Z

1

$pattern = '/<img src=(.*?jpg|gif|png).*?>/m';

$uploadImage = function ($image) {
    $this->uploadPictures();
};

$image_replace = function ($matches) use ($uploadImage) {
    $uploadImage($matches[1]);
    return $matches[1].($matches[2]+1);
};

preg_replace_callback($pattern, $image_replace, $text);

or

$pattern = '/<img src=(.*?jpg|gif|png).*?>/m';

$image_replace = function ($matches) {
    $this->uploadPictures($matches[1]);
    return $matches[1].($matches[2]+1);
};

preg_replace_callback($pattern, $image_replace, $text);

or

$pattern = '/<img src=(.*?jpg|gif|png).*?>/m';

preg_replace_callback($pattern, function ($matches) {
    $this->uploadPictures($matches[1]);
    return $matches[1].($matches[2]+1);
}, $text);

answered Jul 5, 2013 at 9:47

deceze♦

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Comments

DevZer0 · Accepted Answer · 2013-07-05 09:40:49Z

0

You can pass the class object to the anonymous function

$uploadImage = function($image, $this)
{
    $this->uploadPictures();
};

answered Jul 5, 2013 at 9:40

DevZer0

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Comments

rr- · Accepted Answer · 2013-07-05 09:56:56Z

From PHP 5.4 $this can be used in anonymous functions (see changelog here).

Thus, code such as this:

<?php
class A
{
    public function test()
    {
        $f = function()
        {
            return $this->callback();
        };
        return $f();
    }

    public function callback()
    {
        return 'test';
    }
}

$a = new A();
echo $a->test();

is perfectly valid from 5.4 on.

In PHP 5.3 you could achieve the same thing using use operator:

public function test()
{
    $_this = &$this;
    $f = function() use (&$_this)
    {
        return $_this->callback();
    };
    return $f();
}

Prior to PHP 5.3, you could avoid using use keyword through usage of function arguments:

public function test()
{
    $f = function($_this)
    {
        return $_this->callback();
    };
    return $f($this);
}

Finally, when it comes to static methods, you could also make use of __CLASS__ constant.

public function test()
{
    $f = function()
    {
        return call_user_func(array(__CLASS__, 'callback'));
    };
    return $f();
}

...although it's quite ugly.

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