Laravel regex validation for empty string

Question

I have the following validation,
it should match string with letters,numbers,dashes. And empty input should also be valid.
The normal string validation is ok, but I can not make it match "empty" input.

'letter_code' => 'regex:/^[A-Za-z0-9\-]*$/'

letter_code format is invalid

tests:
"C14" // valid
"3.14" // "format is invalid", as expected
"-" // valid
"" // "format is invalid", NOT expected

Is this in a validator? What exactly are you trying to do? Do you want to allow and empty string or make sure it’s not empty? — tptcat
– tptcat, Commented Oct 15, 2017 at 13:44
does 'letter_code' => 'regex:/^[A-Za-z0-9\-]*$/|min:0' work? — Tomalak
– Tomalak, Commented Oct 15, 2017 at 13:48

Sebastian · Accepted Answer · 2018-02-08 10:44:11Z

11

I just found out in laracasts forum, that there is a nullable rule.
You can read about it in the official docs.

Without the nullable rule empty strings are considered invalid if there is a regex rule as well.

answered Feb 8, 2018 at 10:44

Sebastian

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2 Comments

Brian Over a year ago

This is actually the correct answer as compared to the one with more up votes at this time.

Tom Groot Over a year ago

To add to this: in Laravel the ConvertEmptyStringsToNull middleware parses empty strings to null. Without the nullable rule, nulls are considered invalid.

Bostjan · Accepted Answer · 2017-10-15 14:04:13Z

If you don't add required as additional validator empty string must pass

Here is phpunit test:

/** @test */
public function letterCode()
{
    $trans = new \Illuminate\Translation\Translator(
        new \Illuminate\Translation\ArrayLoader, 'en'
    );

    $regex = 'regex:/^[A-Za-z0-9\-]*$/';

    $v = new Validator($trans, ['x' => 'C14'], ['x' => $regex]);
    $this->assertTrue($v->passes());

    $v = new Validator($trans, ['x' => '3.14'], ['x' => $regex]);
    $this->assertFalse($v->passes());

    $v = new Validator($trans, ['x' => '-'], ['x' => $regex]);
    $this->assertTrue($v->passes());

    $v = new Validator($trans, ['x' => ''], ['x' => $regex]);
    $this->assertTrue($v->passes());
}

This is tested with Laravel 5.5

Hefaz · Accepted Answer · 2020-07-22 17:55:06Z

1

I was facing the same problem in Laravel 7.x using GraphQL Types. I needed something similar to this in a field called phone or nothig (empty string). So I did something like this:

'phone' => [
        'name' => 'phone',
        'type' => Type::string(),
        'rules' => ['regex:/^[A-Za-z0-9\-]*$/','nullable']

Here, phone is the name of the field you want to enter text into, and rules is what we define as regex, or NULL.

Hope this helps someone!

answered Jul 22, 2020 at 17:55

Hefaz

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