Add maxbytes: validation rule

[valerio-bozzolan]

Current situation: Laravel already has the max: validation rule, which is good to count human characters (multi-byte).

https://laravel.com/framework/docs/12.x/validation#rule-max

Problem: sometime computers have limitations in bytes, not characters 🤓 For example the MariaDB TEXT field supports 65535 bytes, which really cannot be validated with max:65535 characters.

→ Proposal: a new maxbytes: validation rule 🎉

(This is a follow-up of this merge request: https://gitlab.com/ItalianLinuxSociety/ilsmanager/-/merge_requests/242#note_4161297378 by ValentinNikolaev)

[shaedrich]

Does that mean, you are also in favor of related rules:

• maxgraphemes
• maxcodepoints
• maxutf16be
• maxcesu8

or does it make more sense to add them as flags?

[shaedrich]

I thought of something like

public function rules(): array
{
    return [
        'foo' => ['string:graphenes', 'max:65535'],
        'bar' => ['string:bytes', 'max:65535'],
        'baz' => ['string:codepoints', 'max:65535'],
    ];
}

[valerio-bozzolan]

Cute! Do we already have a similar rule?

[shaedrich]

Yes and no. Semantically, 'integer:strict' is similar, yet, technically it's a bit different, since with 'integer:strict', the strict flag is only applied to the integer rule itself, while string:bytes would initialize a string rule with the bytes flag, which would be applied to the following, string-specific rules, similar to how \Illuminate\Support\Stringable works. So maybe, this would only work as a non-\Stringable rule with its own passes() method:

public function rules(): array
{
    return [
        'foo' => [Rule::string()->as('graphenes')->max(65535)],
        'bar' => [Rule::string()->as('bytes')->max(65535)],
        'baz' => [Rule::string()->as('codepoints')->max(65535)],
    ];
}

[valerio-bozzolan]

Is any other "as(string)" already available? If yes, sounds good!

[shaedrich]

Not in that form, but there are rules where you can add flags like Rule::ip()->version(4) or Rule::distinct()->strict()->ignoreCase() or Rule::email()->rfcCompliant(strict: false)->validateMxRecord()->preventSpoofing(). So, this would be an intuitive fluent API for artisans. Implementation-wise, then String rule would need to be changed from being Stringable to providing its own passes() method, but for the user it would feel the same, so no friction here.

diff

<?php

namespace Illuminate\Validation\Rules;

use Illuminate\Support\Arr;
use Illuminate\Support\Traits\Conditionable;
- use Stringable;

- class StringRule implements Stringable
+ class StringRule
{
    // …

-   /**
-    * Convert the rule to a validation string.
-    */
-   public function __toString(): string
-   {
-       return implode('|', array_unique($this->constraints));
-   }
+   public function max(int $max): self
+   {
+       $this->max = $max;
+
+       return $this;
+   }
+
+   public function as(StringType $as): self
+   {
+       $this->as = $as;
+
+       return $this;
+   }
+
+   /**
+    * {@inheritDoc}
+    */
+   public function passes(): bool
+   {
+       // existing string-specific rules
+       if ($this->max !== null) {
+           $strlen = match ($this->as) {
+               StringType::Graphemes => grapheme_strlen(...),
+               StringType::Bytes => strlen(...),
+               StringType::Characters => mb_strlen(...),
+               StringType::CodePoints => iconv_strlen(...),
+           };
+           if ($strlen($this->value) > $this->max) {
+               return false;
+           }
+       }
+   }

    // …
}