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Krak Validation

The Krak Validation library is a functional and simple approach and interface to validation. It was made out of the need a validation library with a simple interface and configuration. Other leading validators like Respect, Zend, or Symfony have a lot of complexity in their API and adding an actual validator will require adding several classes in some instances.

Krak Validation changes all of this by taking a functional approach to validation where every validator is just a function or instance of Krak\Validation\Validator. This design lends itself easily for extending, custom validators, and decorators. It comes bundled with a Krak\Validation\Kernel which manages validators to provide a simple, fluent, and customizable interface for utilizing validators.

• Installation
• Usage
• Validators
  • Violations
  • Throwing Violations
• Validation Packages
  • Creating a Validation Package
• Core Validation Package
• Doctrine Validation Package
• API

Installation

Install with composer at krak/validation

Usage

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Validators

A validator can be a Krak\Validation\Validator, or any callable that accepts a value and returns null on success and a violation on failure.

Validators implement the following signature:

The second parameter can typically be left out, but is used to pass additional information into the validator. A good example is a PSR Container so that dependencies can be lazy loaded at time of actual validation.

Violations

Creating violations is easy with the violate or violations function. For most validators, you'll simply be creating one violation.

In some cases, one validator can return multiple violations. In that case, we just use the violations to create a violation collection. You can checkout the Krak\Validation\Validators\collection validator to see how to create a violation collection.

Throwing Violations

Once you have a violation or a violation collection, you can optionally throw them as exceptions to be handled upstream.

Asserting Data

A very common practice is using the Validation Kernel to make and validate domain data and then throw a ViolationException if any violations occur. This can be done simply via the assert method.

You can then easily catch the ViolationException upstream and format the violation into readable errors:

Validation Packages

Validation Packages are simple extensions to the Validation\Kernel that register validators and messages into the system.

Creating a Validation Package

To create a validation package, you need to extend the ValidationPackage interface.

From there, you can configure the validation kernel any which way you need.

Typically, you'll just use the validators, messages, and aliases methods to add keyed validations and corresponding methods or aliases.

An example Validation Package would look like:

The validators would be defined in different files like so:

Core Validation Package

The Core Validation package defines a bunch of the normal useful validators.

all

Validates an array with the given validator. If any element in the array fails the validation, a violation will be returned.

Definition: Krak\Validation\Validators\forAll($validator)

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alpha

Wraps the ctype_alpha function and validates a string to verify only alpha characteres.

Definition: Krak\Validation\Validators\alpha()

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alpha_num

Wraps the ctype_alnum function and validates a string to make sure it's alpha numeric.

Definition: Krak\Validation\Validators\alphaNum()

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array

Verifies that the value is an array using is_array.

Definition: Krak\Validation\Validators\typeArray()

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between

Validates a value's size is between two values inclusively.

Definition: Krak\Validation\Validators\between($min, $max)

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boolean

Validates a value is a boolean. true, false, "0", "1", 0, 1 are all instances of boolean.

Definition: Krak\Validation\Validators\typeBoolean()

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date

Validates a string is a valid date using strototime. Anything that strtotime accepts is accepted here.

Definition: Krak\Validation\Validators\date()

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digits

Validates a string is of type digits using the ctype_digits function.

Definition: Krak\Validation\Validators\digits()

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double

Validates a value is a double using is_double.

Definition: Krak\Validation\Validators\double()

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email

Validates that a string matches an email regex.

Definition: Krak\Validation\Validators\regexEmail()

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exists

Alias of required.

float

Validates a value is a float using is_float.

Definition: Krak\Validation\Validators\float()

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in

Validates if a values is within a given array.

Definition: Krak\Validation\Validators\inArray

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integer

Validates that a value is an integer.

Definition: Krak\Validation\Validators\typeInteger()

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length

Validates that a value's size is exactly the given length.

Definition: Krak\Validation\Validators\length($size)

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max

Validates that a value's size is less than or equal to a given max.

Definition: Krak\Validation\Validators\max($max)

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min

Validates that a value's size is greater than or equal to a given min.

Definition: Krak\Validation\Validators\min($min)

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null

Validates that a value's type is null.

Definition: Krak\Validation\Validators\typeNull()

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nullable

Validates that a type is null or not. This is typically used in a chain of validators and will stop validation if the value is null or let the validation continue on else.

Definition: Krak\Validation\Validators\nullable()

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number

Validates that a given value is either a float, double, or integer. This is not the same as is_numeric.

Definition: Krak\Validation\Validators\number()

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numeric

Validates that a given value is numeric using the is_numeric function.

Definition: Krak\Validation\Validators\typeNumeric()

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optional

Validates that a keyed array is optional and is not required to be present in the array. This validator only make sense within the context of a collection.

Definition: Krak\Validation\Validators\optional()

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regex

Validates that a given value is either a float, double, or integer. This is not the same as is_numeric.

Definition: Krak\Validation\Validators\regexMatch($regex, $exclude = false)

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Note defining a regex via the string can be tricky because of how the validation rule parser will validate |, :, and ,. You'll almost always want to call use actual validator itself.

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regex_exclude

Exactly like regex except it matches that the value excludes the specific regular expression.

Definition: Krak\Validation\Validators\regexExclude($regex)

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Note defining a regex via the string can be tricky because of how the validation rule parser will validate |, :, and ,. You'll almost always want to call use actual validator itself.

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required

Validates that a given value is required in a collection. This validator only makes sense within the context of a collection.

Definition: Krak\Validation\Validators\required()

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string

Validates that a given value is a string.

Definition: Krak\Validation\Validators\typeString()

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Doctrine Validation Package

The Doctrine Validation Package defines doctrine related validators.

To enable the doctrine package, you can do the following:

doctrine_all_exist

Validates that a set of strings or integers all exist in a given table.

Definition: class Krak\Validation\Validators\Doctrine\AllExist($table_name, $field = 'id', $type = 'int')

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doctrine_entities

Validates that a a set of ORM Entities exist from a unique key. The given entity name is joined with the doctrine.model_prefix if one is given.

Definition: class Krak\Validation\Validators\Doctrine\Entities($entity_name, $field = 'id')

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doctrine_entity

Validates that an entity exists in the db with the given value.

Definition: class Krak\Validation\Validators\Doctrine\Entity($entity_name, $field = 'id')

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doctrine_exists

Validates that a given value exists in a table in a certain field.

Definition: class Krak\Validation\Validators\Doctrine\Exists($table_name, $field = 'id')

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doctrine_unique

Validates that a given value is unique and doesn't exist in a table in a field.

Definition: class Krak\Validation\Validators\Doctrine\Unique($table_name, $field = 'id')

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doctrine_unique_entity

Validates that a given value exists in a table in a certain field.

Definition: class Krak\Validation\Validators\Doctrine\UniqueEntity($entity_name, $field = 'id')

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API

All of the following are defined in the Krak\Validation\Validators namespace.

collection($validators, $err_on_extra = true)

Validates a map of validators with attribute names mapping to other validators. $err_on_extra is a flag that will determine whether or not to validate if extra fields are in the input array.

This function will return either a Violation, ViolationCollection, or null depending on the input value.

toSize($value)

Gets the size of a variable. If string, it returns the string length. If array, it returns the count, else it assumes numeric and returns the value itself.