PHPerKaigi 2024

Random\Randomizer::getBytesFromString

(PHP 8 >= 8.3.0)

Random\Randomizer::getBytesFromStringGet random bytes from a source string

Description

public Random\Randomizer::getBytesFromString(string $string, int $length): string

Generates a string containing uniformly selected random bytes from the input string with the requested length.

The chance for a byte to be selected is proportional to its share of the input string. If each byte occurs the same amount of times, each byte is equally likely to be selected.

Liste de paramètres

string

The chaîne de caractères from which the returned bytes are selected.

length

The length of the random chaîne de caractères that should be returned in bytes; must be 1 or greater.

Valeurs de retour

A chaîne de caractères containing the requested number of random bytes taken from the input string.

Erreurs / Exceptions

Exemples

Exemple #1 Random\Randomizer::getBytesFromString() example

<?php
$randomizer
= new \Random\Randomizer();

printf(
"%s.example.com",
$randomizer->getBytesFromString('abcdefghijklmnopqrstuvwxyz0123456789', 16)
);
?>

Résultat de l'exemple ci-dessus est similaire à :

3zsw04eiubcf82jd.example.com

Exemple #2 Generate a random code for multi-factor authentication

<?php
// The Secure engine is the default, but we make it explicit, because
// multi-factor codes are security sensitive.
$randomizer = new \Random\Randomizer(new \Random\Engine\Secure());

echo
implode('-', str_split($randomizer->getBytesFromString('0123456789', 20), 5));
?>

Résultat de l'exemple ci-dessus est similaire à :

11551-80418-27047-42075

Exemple #3 Select from a string with a non-uniform distribution

<?php
$randomizer
= new \Random\Randomizer();

echo
$randomizer->getBytesFromString('aaaaabcdef', 20);
?>

Résultat de l'exemple ci-dessus est similaire à :

fddacbeaaeaaacaaaaca

Voir aussi

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