Validator is a nifty form validation library with a small footprint.

Brought to you by the fine folks at KRDS.

Table of contents

• Validating a form

  • Setting validation rules

    • For a single field
    • For multiple fields
      • 'and' rule
      • 'or' rule
      • Break

  • Running the validation

  • Pushing errors manually

  • Full example

• Localization

• Field related functions

  • Getting the error
  • Pushing an error manually
  • Clearing the error
  • Knowing whether the validation passed

• Validation rules

  • Built-in rules
    • Alphanumeric
    • Boolean
    • Date
    • DateHour
    • DependsOn
    • Digits
    • Email
    • Float
    • GreaterThan
    • InArray
    • IsEmpty
    • LengthGreaterThan
    • LengthLowerThan
    • LowerThan
    • NotEmpty
    • Required
    • Unchanged
  • Custom rules
    • Closure
    • Custom function
    • PHP function

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Validating a form

To validate a form, you’ll have define its validation rules first then run the validation.

Start by instantiating a Validator object:

$validator = new Validator;

The methods below can be chained to $validator.

Setting validation rules

A validation rule checks a field against an expected type, format, value, …
The list of rules available is given in Rules section below.

For a single field

First, choose the field you want to apply the rules on:

$validator->field('field_name');

Then, add one or more rules:

$validator->rule(new \Validation\Required);
          ->rule(new \Validation\Email);

For multiple fields

A same rule can be applied to multiple fields. It is called a global rule.
It is useful to avoid repeating the same rule, for example in the case of several fields are required.

A global rule will be applied to each field until calling endGlobalRule function.

There are two type of rules: 'and' and 'or'.

'and' rule

An 'and' rule is applied to each field added after declaring it.
It is the default type of rule.

$validator->globalRule($rule);

'or' rule

An 'or' rule will pass if at least one of the fields added after declaring it passes it.
It is typically used with \Validation\Required, when at least one of X fields must be filled (for example, at least the user landline or mobile phone number).

$validator->globalRule($rule, Validator::OPERATOR_OR, $message);

$message is a required property. It is the user-facing message that will be returned if none of the fields pass the rule.

Break

To end the latest global rule declared:

$validator->endGlobalRule();

Running the validation

To run the validation:

$validator->run($fields);
// returns `true` if the validation passed, `false` otherwise.

$fields is an a list of field name => value, such as $_POST.
This method will return true if the validation passed, false otherwise.

To get the errors messages:

$validator->getErrors();

/* Returns an array:

[
  "field_name" => "Error message",
  "field_name" => "Error message",
  "field_name" => "Error message",
  "_common" => [
    "Common error message",
    "Common error message"
  ]
]

_common errors are errors that apply to the whole form.
*/

Full example

The following examples validates a simple user information form.

$validator = new Validator;

$validator->globalRule(new \Validation\Required)

              ->globalRule(new \Validation\LengthGreaterThan(3))
                  ->field('firstname')
                  ->field('lastname')
              ->endGlobalRule()

              ->field('email')
                  ->rule(new \Validation\Email)

              ->field('dob')
                  ->rule(new \Validation\Dob)

          ->endGlobalRule();

if( ! $validator->run($_POST))
  print_r($validator->getErrors());

Localization

Language files are located in lang/ folder. To choose a language for error messages:

\Validation\i18n::setLanguage($language);

The following languages are currently supported:

• en: English (default)
• fr: French

Field related functions

Getting the error

Returns the error for a field as a FieldError object.
Use $error->getMessage() to get the error message.

If no error, returns null.

$error	=	$validator->field('field_name')->getError();
echo $error->getMessage();

Pushing an error manually

In some case, you might need to push some error messages manually.

• Push an error for a field:

  $validator->field('field_name')->error('MyField error message');

• Push an error related to the whole form:

  $validator->globalError('Global error message');

Clearing the error

Clear the error of a field and set it as if the validation passed.

$validator->field('field_name')->clearError();

Knowing whether the validation passed

To know whether a field has been given and passed the validation.

$validator->field('field_name')->ok();

// return `true` if the field is NOT missing and the validation passed, `false` otherwise.

Validation rules

Validation rules are executed only if the field is present (that means, given on the array, it might be empty).

• If a field equals null, it is considered missing;
• if a field equals "null" (as a string), it is considered empty.
  This is typically useful if you are using any kind of API console which removes the empty fields before making the call.

Built-in rules

Alphanumeric

Validates an alphanumeric string.

Boolean

Validates a boolean value.

Can be: true / false / 1 / 0 / "1" / "0" / ""

Date

Validates a date in YYYY-MM-DD HH:MM format.

DateHour

Validates a date + hour in YYYY-MM-DD HH:MM format.

DependsOn

This validation rule has to be placed at the top of the rules declaration for a field. It will block the other validation rules in the stack if another field is missing of invalid.

This validation rule won’t generate an error message by default in case of failure. It can be shown anyway if $displayable param of Validator::run is set to true`.

new \Validation\DependsOn($field)

• $field is the name of the field it depends on

Digits

Validates a field made of digits only.

Can be either of type string or int.

Email

Validates an email address.

Float

Validates a float value.

Can be either of type string or int.
The decimal separator can be either a point (.) or a comma (,).

GreaterThan

Validates a value greater than another value. Can validate numbers or dates.

new \Validation\GreaterThan($number[, $type])

• $number is the number that should be the lowest
• $type can be set to \Validation\GreaterThan::TYPE_DATE to compare dates

InArray

Validates a value part of a pre-defined list.

new \Validation\InArray($list[, $ignore_case = false])

• $list: List of values the validated value should belong to
• $ignore_case: If true, the case will be ignored for searching through the array

IsEmpty

Validates a required but empty field.

LengthGreaterThan

Validates a length greater than a given length.

new \Validation\LengthGreaterThan($length)

• $length: Length for which the field must be greater than.

LengthLowerThan

Validates a length lower than a given length.

new \Validation\LengthLowerThan($length)

• $length: Length for which the field must be lower than.

LowerThan

Validates a value lower than another value. Can validate numbers or dates.

new \Validation\LowerThan($number[, $type = \Validation\GreaterThan::TYPE_NUMBER])

• $number is the number that should be the greatest
• $type can be set to \Validation\GreaterThan::TYPE_DATE` to compare dates

NotEmpty

Validates a required and non-empty field.

Required

Validates a required field.

Unchanged

Validates that the value has not been changed.

new \Validation\Unchanged($reference)

• $reference is the reference value to be checked against

Custom rules

You can give custom rules to validate a field.

Closure

$validator->rule(function($value, $values, $validator) {

  /**
   * Remove the parameters you won’t use
   * (typically, only $value is interesting)
   **/
 
  if(isUsernameTaken($value))
    throw new Exception('This username is already taken. Please choose another one.');

});

• $value is the value checked
• $valuesis the list of all the values
• $validator is the Validator object

Custom function

Public static function:

$validator->rule('CustomValidation::ruleName');

// Will call: CustomValidation::ruleName($value)

PHP function

A PHP function that takes a single parameter can be given.
The validation will fail if the function returns a “falsy” value (empty, 0, false, null, …).

$validator->rule('is_scalar');

// Will call: is_scalar($value)