Colin O’Dell introduced a PHP library called Indentation, that can be utilized to detect and manipulate the indentation of files and strings.

Installation

You can install this package via composer:

composer require --dev colinodell/indentation

Usage

Detecting the indentation of a string or file

use ColinODell\Indentation\Indentation;

$indentation = Indentation::detect(file_get_contents('composer.json'));

assert($indentation->getAmount() === 4);
assert($indentation->getType() === Indentation::TYPE_SPACE);
assert((string)$indentation === '    ');

Changing the indentation of a string or file

use ColinODell\Indentation\Indentation;

$composerJson = file_get_contents('composer.json');
$composerJson = Indentation::change($composerJson, new Indentation(1, Indentation::TYPE_TAB));
file_put_contents('composer.json', $composerJson);

Adding leading indentation to all lines

Need to add indent all lines by some amount?

use ColinODell\Indentation\Indentation;

$codeExample = file_get_contents('file.php');
$indented = Indentation::indent($codeExample, new Indentation(4, Indentation::TYPE_SPACE));

Now you can embed the indented code into a Markdown document!

Removing leading indentation from all lines

Imagine you have a file where every line is indented by at least 4 spaces:

    /**
     * Just a silly example
     */
    class Cat extends Animal
    {
        // ...
    }

You can trim that leading indentation while preserving the nested indentation with the unindent() method:

use ColinODell\Indentation\Indentation;

$contents = file_get_contents('Cat.php');
$trimmed = Indentation::unindent($contents);
file_put_contents('Cat.php', $trimmed);

Giving you:

/**
 * Just a silly example
 */
class Cat extends Animal
{
    // ...
}

Note how the leading 4 spaces are removed but all other indentation (like in the docblock and method body) is preserved.

For more details about this package, you can visit Github