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Faker#

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Faker is a PHP library that generates fake data for you. Whether you need to bootstrap your database, create good-looking XML documents, fill-in your persistence to stress test it, or anonymize data taken from a production service, Faker is for you.

It's heavily inspired by Perl's Data::Faker, and by Ruby's Faker.

Installation#

Faker requires PHP >= 7.1.

composer require fakerphp/faker

Basic Usage#

Autoloading#

Faker supports both PSR-0 as PSR-4 autoloaders.

// when installed via composer
require_once 'vendor/autoload.php';

You can also load Fakers shipped PSR-0 autoloader

// load Faker autoloader
require_once '/path/to/Faker/src/autoload.php';

alternatively, you can use any other PSR-4 compliant autoloader

Create fake data#

Use Faker\Factory::create() to create and initialize a faker generator, which can generate data by calling methods named after the type of data you want.

require_once 'vendor/autoload.php';

// use the factory to create a Faker\Generator instance
$faker = Faker\Factory::create();
// generate data by calling methods
echo $faker->name();
// 'Vince Sporer'
echo $faker->email();
// 'walter.sophia@hotmail.com'
echo $faker->text();
// 'Numquam ut mollitia at consequuntur inventore dolorem.'

Each call to $faker->name() yields a different (random) result. This is because Faker uses __call() magic, and forwards Faker\Generator->$method() calls to Faker\Generator->format($method, $attributes).

for ($i = 0; $i < 3; $i++) {
    echo $faker->name() . "\n";
}

// 'Cyrus Boyle'
// 'Alena Cummerata'
// 'Orlo Bergstrom'

Modifiers#

Faker provides three special providers, unique(), optional(), and valid(), to be called before any provider.

// unique() forces providers to return unique values
$values = [];
for ($i = 0; $i < 10; $i++) {
    // get a random digit, but always a new one, to avoid duplicates
    $values []= $faker->unique()->randomDigit();
}
print_r($values); // [4, 1, 8, 5, 0, 2, 6, 9, 7, 3]

// providers with a limited range will throw an exception when no new unique value can be generated
$values = [];
try {
    for ($i = 0; $i < 10; $i++) {
        $values []= $faker->unique()->randomDigitNotNull();
    }
} catch (\OverflowException $e) {
    echo "There are only 9 unique digits not null, Faker can't generate 10 of them!";
}

// you can reset the unique modifier for all providers by passing true as first argument
$faker->unique($reset = true)->randomDigitNotNull(); // will not throw OverflowException since unique() was reset
// tip: unique() keeps one array of values per provider

// optional() sometimes bypasses the provider to return a default value instead (which defaults to NULL)
$values = [];
for ($i = 0; $i < 10; $i++) {
    // get a random digit, but also null sometimes
    $values []= $faker->optional()->randomDigit();
}
print_r($values); // [1, 4, null, 9, 5, null, null, 4, 6, null]

// optional() accepts a weight argument to specify the probability of receiving the default value.
// 0 will always return the default value; 1.0 will always return the provider. Default weight is 0.5 (50% chance).
// Please note that the weight can be provided as float (0 / 1.0) or int (0 / 100)

// As float
$faker->optional($weight = 0.1)->randomDigit(); // 90% chance of NULL
$faker->optional($weight = 0.9)->randomDigit(); // 10% chance of NULL

// As int
$faker->optional($weight = 10)->randomDigit; // 90% chance of NULL
$faker->optional($weight = 100)->randomDigit; // 0% chance of NULL

// optional() accepts a default argument to specify the default value to return.
// Defaults to NULL.
$faker->optional($weight = 0.5, $default = false)->randomDigit(); // 50% chance of FALSE
$faker->optional($weight = 0.9, $default = 'abc')->word(); // 10% chance of 'abc'

// valid() only accepts valid values according to the passed validator functions
$values = [];
$evenValidator = function($digit) {
    return $digit % 2 === 0;
};
for ($i = 0; $i < 10; $i++) {
    $values []= $faker->valid($evenValidator)->randomDigit();
}
print_r($values); // [0, 4, 8, 4, 2, 6, 0, 8, 8, 6]

// just like unique(), valid() throws an overflow exception when it can't generate a valid value
$values = [];
try {
    $faker->valid($evenValidator)->randomElement([1, 3, 5, 7, 9]);
} catch (\OverflowException $e) {
    echo "Can't pick an even number in that set!";
}

If you would like to use a modifier with a value not generated by Faker, use the passthrough() method. passthrough() simply returns whatever value it was given.

$faker->optional()->passthrough(mt_rand(5, 15));

Localization#

Faker\Factory can take a locale as an argument, to return localized data. If no localized provider is found, the factory falls back to the default locale (en_US).

// create a French faker
$faker = Faker\Factory::create('fr_FR');
for ($i = 0; $i < 3; $i++) {
    echo $faker->name() . "\n";
}

// Luce du Coulon
// Auguste Dupont
// Roger Le Voisin

You can check available Faker locales in the source code, under the Provider directory. The localization of Faker is an ongoing process, for which we need your help. Don't hesitate to create localized providers to your own locale and submit a PR!

Seeding the Generator#

You may want to always get the same generated data - for instance when using Faker for unit testing purposes. The generator offers a seed() method, which seeds the random number generator. Calling the same script twice with the same seed produces the same results.

$faker = Faker\Factory::create();
$faker->seed(1234);

echo $faker->name(); // 'Jess Mraz I';
Tip

DateTime formatters won't reproduce the same fake data if you don't fix the $max value:

// even when seeded, this line will return different results because $max varies
$faker->dateTime(); // equivalent to $faker->dateTime($max = 'now')
// make sure you fix the $max parameter
$faker->dateTime('2014-02-25 08:37:17'); // will return always the same date when seeded
Tip

Formatters won't reproduce the same fake data if you use the rand() php function. Use $faker or mt_rand() instead:

// bad
$faker->realText(rand(10, 20));
// good
$faker->realText($faker->numberBetween(10, 20));

Faker Internals: Understanding Providers#

A Faker\Generator alone can't do much generation. It needs Faker\Provider objects to delegate the data generation to them. Faker\Factory::create() actually creates a Faker\Generator bundled with the default providers. Here is what happens under the hood:

$faker = new Faker\Generator();
$faker->addProvider(new Faker\Provider\en_US\Person($faker));
$faker->addProvider(new Faker\Provider\en_US\Address($faker));
$faker->addProvider(new Faker\Provider\en_US\PhoneNumber($faker));
$faker->addProvider(new Faker\Provider\en_US\Company($faker));
$faker->addProvider(new Faker\Provider\Lorem($faker));
$faker->addProvider(new Faker\Provider\Internet($faker));

Whenever you try to access a property on the $faker object, the generator looks for a method with the same name in all the providers attached to it. For instance, calling $faker->name triggers a call to Faker\Provider\Person::name(). And since Faker starts with the last provider, you can easily override existing formatters: just add a provider containing methods named after the formatters you want to override.

That means that you can easily add your own providers to a Faker\Generator instance. A provider is usually a class extending \Faker\Provider\Base. This parent class allows you to use methods like lexify() or randomNumber(); it also gives you access to formatters of other providers, through the protected $generator property. The new formatters are the public methods of the provider class.

Here is an example provider for populating Book data:

namespace Faker\Provider;

class Book extends \Faker\Provider\Base
{
  public function title($nbWords = 5)
  {
    $sentence = $this->generator->sentence($nbWords);
    return substr($sentence, 0, strlen($sentence) - 1);
  }

  public function ISBN()
  {
    return $this->generator->ean13();
  }
}

To register this provider, just add a new instance of \Faker\Provider\Book to an existing generator:

$faker->addProvider(new \Faker\Provider\Book($faker));

Now you can use the two new formatters like any other Faker formatter:

$book = new Book();
$book->setTitle($faker->title());
$book->setISBN($faker->ISBN());
$book->setSummary($faker->text());
$book->setPrice($faker->randomNumber(2));
Tip

A provider can also be a Plain Old PHP Object. In that case, all the public methods of the provider become available to the generator.

Language specific formatters#

Supported locales can be found under the "Locales" header on the left.

Misnamed locales#

Current name Correct name
at_AT de_AT
zh_CN zh_Hans_CN
zh_TW zh_Hant_TW

Source: https://www.localeplanet.com/icu/

License#

Faker is released under the MIT License. See the bundled LICENSE file for details.