customizing-data-generation.md

Customizing Data Generation

1. Faker Data
   1. Localized Fake Data
   2. Random data
   3. Default Providers
      1. Identity
      2. Current
      3. Cast
2. Custom Faker Data Providers

Faker Data

Alice integrates with the Faker library. Using <foo()> you can call Faker data providers to generate random data. Check the list of Faker providers.

Let's turn our static bob user into a randomized entry:

Nelmio\Entity\User:
    user{1..10}:
        username: '<username()>'
        fullname: '<firstName()> <lastName()>'
        birthDate: '<date_create()>'
        email: '<email()>'
        favoriteNumber: '<numberBetween(1, 200)>'

As you see in the last line, you can also pass arguments to those just as if you were calling a function.

Random data

The underlying Faker library is using a seed for its data generators which if set (this is the default) will ensure you will get the same data between two loadings.

If you wish to generate different data on each loading, you can reset the seed by overriding the getSeed() method when using the NativeLoader or the the parameter nelmio_alice.seed if you are using Symfony.

Localized Fake Data

Faker can create localized data for addresses, phone numbers and so on. You can set the default locale to use by configuring the locale value used by Faker generator. With NativeLoader, this can be done by overriding the createFakerGenerator() method. In Symfony, override the nelmio_alice.faker.generator service.

Additionally, you can mix locales by adding a locale prefix to the faker key, i.e. <fr_FR:phoneNumber()> or <de_DE:firstName()>.

Default Providers

Alice default Faker provider can be found in AliceProvider.

Identity

Alice includes a default identity provider, <identity()>, that evaluates whatever is passed to it and returns the evaluated value. As a result, you can use it to do arithmetic operations such as <identity(1 * 2)> or use PHP expressions like <identity(new \DateTimeImmutable('2016-09-16'))>.

The identity function supports still references and variables so you can still do <identity($favoriteNumber * @user1->favoriteNumber)>. The value of current, usually used with <current()>, is accessible via the $current variable.

Some syntactic sugar is provided for this as well, and <($whatever)> is an alias for <identity($whatever)>.

Current

Returns the current value in the context of a collection:

stdClass:
    dummy{1..2}:
        currentValue: <current()> # is equivalent to '$current'

Cast

The cast method was added at some point, but you should use PHP internals like intval or boolval instead:

stdClass:
    dummy{1..2}:
        intval: <intval("1")>
        boolval: <boolval(1)>

Custom Faker Data Providers

Sometimes you need more than what Faker and Alice provide you natively. For that, you can register a custom Faker Provider class:

<?php

namespace App\Faker\Provider;

use Faker\Provider\Base as BaseProvider;

final class JobProvider extends BaseProvider
{
   /**
    * Sources: {@link http://siliconvalleyjobtitlegenerator.tumblr.com/}
    *
    * @var array List of job titles.
    */
   const TITLE_PROVIDER = [
       'firstname' => [
           'Audience Recognition',
           'Big Data',
           'Bitcoin',
           '...',
           'Video Experience',
           'Wearables',
           'Webinar',
       ],
       'lastname' => [
           'Advocate',
           'Amplifier',
           'Architect',
           '...',
           'Warlock',
           'Watchman',
           'Wizard',
       ],
       'fullname' => [
           'Conductor of Datafication',
           'Crowd-Funder-in-Residence',
           'Quantified-Self-in-Residence',
           '...',
           'Tech-Svengali-in-Residence',
           'Tech-Wizard-in-Residence',
           'Thought-Leader-in-Residence',
       ],
   ];

   /**
    * Sources: {@link http://sos.uhrs.indiana.edu/Job_Code_Title_Abbreviation_List.htm}
    *
    * @var array List of job abbreviations.
    */
   const ABBREVIATION_PROVIDER = [
       'ABATE',
       'ACAD',
       'ACCT',
       '...',
       'WCTR',
       'WSTRN',
       'WKR',
   ];

   /**
    * @return string Random job title.
    */
   public function jobTitle()
   {
       $names = [
           sprintf(
               '%s %s',
               self::randomElement(self::TITLE_PROVIDER['firstname']),
               self::randomElement(self::TITLE_PROVIDER['lastname'])
           ),
           self::randomElement(self::TITLE_PROVIDER['fullname']),
       ];

       return self::randomElement($names);
   }

   /**
    * @return string Random job abbreviation title
    */
   public function jobAbbreviation()
   {
       return self::randomElement(self::ABBREVIATION_PROVIDER);
   }
}

Then you can add it to the Faker Generator used by Alice by either overriding the NativeLoader::createFakerGenerator() method.

If you are using Symfony, custom Faker providers are registered by adding the tag nelmio_alice.faker.provider to the services. Note that this is automatically done if your service extends Faker\Provider\Base and have autoconfigure and autowire enabled:

# config/services.yaml

services:
    _defaults:
        autowire: true
        autoconfigure: true

    App\Faker\Provider\JobProvider: ~

or:

# config/services.yaml

services:
    App\Faker\Provider\JobProvider:
        arguments:
            - '@Faker\Generator'
        tags: [ { name: nelmio_alice.faker.provider } ]

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