Add FILTER_VALIDATE_STRLEN for UTF-8 string length validation

[masakielastic]

Description

I would like to propose a new filter validator FILTER_VALIDATE_STRLEN that validates the length of a UTF-8 string.

The length is counted in Unicode code points. Grapheme clusters are not considered.

The validator supports min_len and max_len options and does not depend on the mbstring extension.

A prototype implementation is provided in the accompanying pull request.

$options = [
    'options' => [
        'max_len' => 2,
        'default' => 'error',
    ],
];

var_dump(
    filter_var('🐘🐘🐘', FILTER_VALIDATE_STRLEN, $options)
);

[iluuu1994]

Hi @masakielastic. New functionality requires a discussion on the mailing list and likely an RFC. Please proceed accordingly if you'd like to see this progress.

[masakielastic]

Thanks for the guidance.

I have requested PHP wiki write access via the internals mailing list
and am preparing the RFC.

I will share the RFC once it is published.

Thanks!

[masakielastic]

The RFC has been published on the wiki:

https://wiki.php.net/rfc/filter_validate_strlen

Thank you @iluuu1994 for granting me wiki access.

[youkidearitai]

Please see: https://wiki.php.net/rfc/howto

[iluuu1994]

@masakielastic Thanks for taking initiative. The next step will be to announce the RFC on the mailing list, as described in https://wiki.php.net/rfc/howto.

[github-actions]

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