02-feature-guide.md

Feature Guide

Namespace import

Respect\Validation is namespaced, but you can make your life easier by importing a single class into your context:

use Respect\Validation\Validator as v;

Simple validation

The Hello World validator is something like this:

$number = 123;
v::numericVal()->validate($number); // true

Chained validation

It is possible to use validators in a chain. Sample below validates a string containing numbers and letters, no whitespace and length between 1 and 15.

$usernameValidator = v::alnum()->noWhitespace()->length(1, 15);
$usernameValidator->validate('alganet'); // true

Validating object properties

Given this simple object:

$user = new stdClass;
$user->name = 'Alexandre';
$user->birthdate = '1987-07-01';

Is possible to validate its properties in a single chain:

$userValidator = v::property('name', v::stringType()->length(1, 32))
                  ->property('birthdate', v::date()->minAge(18));

$userValidator->validate($user); // true

Validating array keys is also possible using v::key()

Note that we used v::stringType() and v::dateTime() in the beginning of the validator. Although is not mandatory, it is a good practice to use the type of the validated object as the first node in the chain.

Validating array keys and values

Validating array keys into another array is also possible using Key.

If we got the array below:

$data = [
    'parentKey' => [
        'field1' => 'value1',
        'field2' => 'value2'
        'field3' => true,
    ]
];

Using the next combination of rules, we can validate child keys.

v::key(
    'parentKey',
    v::key('field1', v::stringType())
        ->key('field2', v::stringType())
        ->key('field3', v::boolType())
    )
    ->assert($data); // You can also use check() or validate()

Input optional

On oldest versions of Respect\Validation all validators treat input as optional and accept an empty string input as valid. Even though a useful feature that caused a lot of troubles for our team and neither was an obvious behavior. Also there was some people who likes to accept null as optional value, not only an empty string.

For that reason all rules are mandatory now but if you want to treat a value as optional you can use v::optional() rule:

v::alpha()->validate(''); // false input required
v::alpha()->validate(null); // false input required

v::optional(v::alpha())->validate(''); // true
v::optional(v::alpha())->validate(null); // true

By optional we consider null or an empty string ('').

See more on Optional.

Negating rules

You can use the v::not() to negate any rule:

v::not(v::intVal())->validate(10); // false, input must not be integer

Validator reuse

Once created, you can reuse your validator anywhere. Remember $usernameValidator?

$usernameValidator->validate('respect');            //true
$usernameValidator->validate('alexandre gaigalas'); // false
$usernameValidator->validate('#$%');                //false

Exception types

• Respect\Validation\Exceptions\Exception:
  • All exceptions implement this interface;
• Respect\Validation\Exceptions\ValidationException:
  • Implements the Respect\Validation\Exceptions\Exception interface
  • Thrown when the check() fails
  • All validation exceptions extend this class
  • Available methods:
    • getMessage();
    • updateMode($mode);
    • updateTemplate($template);
• Respect\Validation\Exceptions\NestedValidationException:
  • Extends the Respect\Validation\Exceptions\ValidationException class
  • Usually thrown when the assert() fails
  • Available methods:
    • getFullMessage();
    • getMessages();

Informative exceptions

When something goes wrong, Validation can tell you exactly what's going on. For this, we use the assert() method instead of validate():

use Respect\Validation\Exceptions\NestedValidationException;

try {
    $usernameValidator->assert('really messed up screen#name');
} catch(NestedValidationException $exception) {
   echo $exception->getFullMessage();
}

The printed message is exactly this, as a nested Markdown list:

- All of the required rules must pass for "really messed up screen#name"
  - "really messed up screen#name" must contain only letters (a-z) and digits (0-9)
  - "really messed up screen#name" must not contain whitespace
  - "really messed up screen#name" must have a length between 1 and 15

Getting all messages as an array

If you want to get all the messages as an array you can use getMessages() for that. The getMessages() method returns an array with all the messages.

try {
    $usernameValidator->assert('really messed up screen#name');
} catch(NestedValidationException $exception) {
    print_r($exception->getMessages());
}

The getMessages() returns an array in which the keys are the name of the validators, or its reference in case you are using Key or Property rule:

Array
(
    [alnum] => "really messed up screen#name" must contain only letters (a-z) and digits (0-9)
    [noWhitespace] => "really messed up screen#name" must not contain whitespace
    [length] => "really messed up screen#name" must have a length between 1 and 15
)

Custom messages

Getting messages as an array is fine, but sometimes you need to customize them in order to present them to the user. This is possible using the getMessages() method as well by passing the templates as an argument:

try {
    $usernameValidator->assert('really messed up screen#name', [
        'alnum' => '{{name}} must contain only letters and digits',
        'noWhitespace' => '{{name}} cannot contain spaces',
        'length' => '{{name}} must not have more than 15 chars',
    ]);
} catch(NestedValidationException $exception) {
    print_r($exception->getMessages());
}

For all messages, the {{name}} variable is available for templates. If you do not define a name it uses the input to replace this placeholder.

The result of the code above will be:

Array
(
    [alnum] => "really messed up screen#name" must contain only letters and digits
    [noWhitespace] => "really messed up screen#name" cannot contain spaces
    [length] => "really messed up screen#name" must not have more than 15 chars
)

Note that getMessage() will only return a message when the specific validation in the chain fails.

Validator name

On v::property() and v::key(), {{name}} is the property/key name. For others, is the same as the input. You can customize a validator name using:

v::dateTime('Y-m-d')->between('1980-02-02', 'now')->setName('Member Since');

Validation methods

We've seen validate() that returns true or false and assert() that throws a complete validation report. There is also a check() method that returns an Exception only with the first error found:

use Respect\Validation\Exceptions\ValidationException;

try {
    $usernameValidator->check('really messed up screen#name');
} catch(ValidationException $exception) {
    echo $exception->getMessage();
}

Message:

"really messed up screen#name" must contain only letters (a-z) and digits (0-9)