Validation::Class - Powerful Data Validation Framework

version 7.900059

use Validation::Class::Simple::Streamer;

my  $params = {username => 'admin', password => 's3cret'};
my  $input  = Validation::Class::Simple::Streamer->new(params => $params);

# check username parameter
$input->check('username')->required->between('5-255');
$input->filters([qw/trim strip/]);

# check password parameter
$input->check('password')->required->between('5-255')->min_symbols(1);
$input->filters([qw/trim strip/]);

# run validate
$input->validate or die $input->errors_to_string;

Validation::Class is a scalable data validation library with interfaces for applications of all sizes. The most common usage of Validation::Class is to transform class namespaces into data validation domains where consistency and reuse are primary concerns. Validation::Class provides an extensible framework for defining reusable data validation rules. It ships with a complete set of pre-defined validations and filters referred to as "directives".

The core feature-set consist of self-validating methods, validation profiles, reusable validation rules and templates, pre and post input filtering, class inheritance, automatic array handling, and extensibility (e.g. overriding default error messages, creating custom validators, creating custom input filters and much more). Validation::Class promotes DRY (don't repeat yourself) code. The main benefit in using Validation::Class is that the architecture is designed to increase the consistency of data input handling. The following is a more traditional usage of Validation::Class, using the DSL to construct a validator class:

package MyApp::Person;

use Validation::Class;

# data validation template
mixin basic     => {
    required    => 1,
    max_length  => 255,
    filters     => [qw/trim strip/]
};

# data validation rules for the username parameter
field username  => {
    mixin       => 'basic',
    min_length  => 5
};

# data validation rules for the password parameter
field password  => {
    mixin       => 'basic',
    min_length  => 5,
    min_symbols => 1
};

package main;

my $person = MyApp::Person->new(username => 'admin', password => 'secr3t');

# validate rules on the person object
unless ($person->validates) {
    # handle the failures
    warn $person->errors_to_string;
}

1;

If you are looking for a simple in-line data validation module built using the same tenets and principles as Validation::Class, please review Validation::Class::Simple or Validation::Class::Simple::Streamer. If you are new to Validation::Class, or would like more information on the underpinnings of this library and how it views and approaches data validation, please review Validation::Class::Whitepaper. Please review the "GUIDED-TOUR" in Validation::Class::Cookbook for a detailed step-by-step look into how Validation::Class works.

The adopt keyword (or adt) copies configuration and functionality from other Validation::Class classes. The adopt keyword takes three arguments, the name of the class to be introspected, and the configuration type and name to be recreated. Basically, anything you can configure using a Validation::Class keyword can be adopted into other classes using this keyword with the exception of coderefs registered using the build keyword. Please note! If you are adopting a field declaration which has an associated mixin directive defined on the target class, you must adopt the mixin explicitly if you wish it's values to be interpolated.

package MyApp::Exployee;

use Validate::Class;
use MyApp::Person;

adopt MyApp::Person, mixin   => 'basic';
adopt MyApp::Person, field   => 'first_name';
adopt MyApp::Person, field   => 'last_name';
adopt MyApp::Person, profile => 'has_fullname';

1;

The attribute keyword (or has) registers a class attribute, i.e. it creates an accessor (getter and setter) on the class. Attribute declaration is flexible and only requires an attribute name to be configured. Additionally, the attribute keyword can takes two arguments, the attribute's name and a scalar or coderef to be used as it's default value.

package MyApp::Person;

use Validate::Class;

attribute 'first_name' => 'Peter';
attribute 'last_name'  => 'Venkman';
attribute 'full_name'  => sub {
    join ', ', $_[0]->last_name, $_[0]->first_name
};

attribute 'email_address';

1;

The build keyword (or bld) registers a coderef to be run at instantiation much in the same way the common BUILD routine is used in modern OO frameworks.

package MyApp::Person;

use Validation::Class;

build sub {

    my ($self, $args) = @_;

    # run after instantiation in the order defined

};

1;

The build keyword takes one argument, a coderef which is passed the instantiated class object.

The directive keyword (or dir) registers custom validator directives to be used in your field definitions. Please note that custom directives can only be used with field definitions. This is a means of extending the list of directives per instance. See the list of core directives, Validation::Class::Directives, or review Validation::Class::Directive for insight into creating your own CPAN installable directives.

package MyApp::Person;

use Validate::Class;

# define a custom class-level directive
directive 'blacklisted' => sub {

    my ($self, $field, $param) = @_;

    if (defined $field->{blacklisted} && defined $param) {
        if ($field->{required} || $param) {
            if (exists_in_blacklist($field->{blacklisted}, $param)) {
                my $handle = $field->label || $field->name;
                $field->errors->add("$handle has been blacklisted");
                return 0;
            }
        }
    }

    return 1;

};

field 'email_address' => {
    blacklisted => '/path/to/blacklist'
    email => 1,
};

1;

The directive keyword takes two arguments, the name of the directive and a coderef which will be used to validate the associated field. The coderef is passed four ordered parameters; a directive object, the class prototype object, the current field object, and the matching parameter's value. The validator (coderef) is evaluated by its return value as well as whether it altered any error containers.

The document keyword (or doc) registers a data matching profile which can be used to validate heiarchal data. It will store a hashref with pre-define path matching rules for the data structures you wish to validate. The "path matching rules", which use a specialized object notation, referred to as the document notation, can be thought of as a kind-of simplified regular expression which is executed against the flattened data structure. The following are a few general use-cases:

package MyApp::Person;

use Validation::Class;

field  'string' => {
    mixin => [':str']
};

# given this JSON data structure
{
    "id": "1234-A",
    "name": {
        "first_name" : "Bob",
        "last_name"  : "Smith",
     },
    "title": "CIO",
    "friends" : [],
}

# select id to validate against the string rule
document 'foobar'  =>
    { 'id' => 'string' };

# select name -> first_name/last_name to validate against the string rule
document 'foobar'  =>
    {'name.first_name' => 'string', 'name.last_name' => 'string'};

# or
document 'foobar'  =>
    {'name.*_name' => 'string'};

# select each element in friends to validate against the string rule
document 'foobar'  =>
    { 'friends.@'  => 'string' };

# or select an element of a hashref in each element in friends to validate
# against the string rule
document 'foobar'  =>
    { '[email protected]' => 'string' };

The document declaration's keys should follow the aforementioned document notation schema and it's values should be strings which correspond to the names of fields (or other document declarations) that will be used to preform the data validation. It is possible to combine document declarations to validate hierarchical data that contains data structures matching one or more document patterns. The following is an example of what that might look like.

package MyApp::Person;

use Validation::Class;

# data validation rule
field  'name' => {
    mixin      => [':str'],
    pattern    => qr/^[A-Za-z ]+$/,
    max_length => 20,
};

# data validation map / document notation schema
document 'friend' => {
    'name' => 'name'
};

# data validation map / document notation schema
document 'person' => {
    'name' => 'name',
    'friends.@' => 'friend'
};

package main;

my $data = {
    "name"   => "Anita Campbell-Green",
    "friends" => [
        { "name" => "Horace" },
        { "name" => "Skinner" },
        { "name" => "Alonzo" },
        { "name" => "Frederick" },
    ],
};

my $person = MyApp::Person->new;

unless ($person->validate_document(person => $data)) {
    warn $person->errors_to_string if $person->error_count;
}

1;

Alternatively, the following is a more verbose data validation class using traditional styling and configuration.

package MyApp::Person;

use Validation::Class;

field  'id' => {
    mixin      => [':str'],
    filters    => ['numeric'],
    max_length => 2,
};

field  'name' => {
    mixin      => [':str'],
    pattern    => qr/^[A-Za-z ]+$/,
    max_length => 20,
};

field  'rating' => {
    mixin      => [':str'],
    pattern    => qr/^\-?\d+$/,
};

field  'tag' => {
    mixin      => [':str'],
    pattern    => qr/^(?!evil)\w+/,
    max_length => 20,
};

document 'person' => {
    'id'                             => 'id',
    'name'                           => 'name',
    'company.name'                   => 'name',
    'company.supervisor.name'        => 'name',
    'company.supervisor.rating.@.*'  => 'rating',
    'company.tags.@'                 => 'name'
};

package main;

my $data = {
    "id"      => "1234-ABC",
    "name"    => "Anita Campbell-Green",
    "title"   => "Designer",
    "company" => {
        "name"       => "House of de Vil",
        "supervisor" => {
            "name"   => "Cruella de Vil",
            "rating" => [
                {   "support"  => -9,
                    "guidance" => -9
                }
            ]
        },
        "tags" => [
            "evil",
            "cruelty",
            "dogs"
        ]
    },
};

my $person = MyApp::Person->new;

unless ($person->validate_document(person => $data)) {
    warn $person->errors_to_string if $person->error_count;
}

1;

Additionally, the following is yet another way to validate a document by passing the document specification directly instead of by name.

package MyApp::Person;

use Validation::Class;

package main;

my $data = {
    "id"      => "1234-ABC",
    "name"    => "Anita Campbell-Green",
    "title"   => "Designer",
    "company" => {
        "name"       => "House of de Vil",
        "supervisor" => {
            "name"   => "Cruella de Vil",
            "rating" => [
                {   "support"  => -9,
                    "guidance" => -9
                }
            ]
        },
        "tags" => [
            "evil",
            "cruelty",
            "dogs"
        ]
    },
};

my $spec = {
    'id'                            => { max_length => 2 },
    'name'                          => { mixin      => ':str' },
    'company.name'                  => { mixin      => ':str' },
    'company.supervisor.name'       => { mixin      => ':str' },
    'company.supervisor.rating.@.*' => { pattern    => qr/^(?!evil)\w+/ },
    'company.tags.@'                => { max_length => 20 },
};

my $person = MyApp::Person->new;

unless ($person->validate_document($spec => $data)) {
    warn $person->errors_to_string if $person->error_count;
}

1;

The ensure keyword (or ens) is used to convert a pre-existing method into an auto-validating method. The auto-validating method will be registered and function as if it was created using the method keyword. The original pre-existing method will be overridden with a modified version which performs the pre and/or post validation routines.

package MyApp::Person;

use Validation::Class;

sub register {
    ...
}

ensure register => {
    input  => ['name', '+email', 'username', '+password', '+password2'],
    output => ['+id'], # optional output validation, dies on failure
};

package main;

my $person = MyApp::Person->new(params => $params);

if ($person->register) {
    # handle the successful registration
}

1;

The ensure keyword takes two arguments, the name of the method to be overridden and a hashref of required key/value pairs. The hashref may have an input key (e.g. input, input_document, input_profile, or input_method). The `input` key (specifically) must have a value which must be either an arrayref of fields to be validated, or a scalar value which matches (a validation profile or auto-validating method name). The hashref may also have an output key (e.g. output, output_document, output_profile, or output_method). The `output` key (specifically) must have a value which must be either an arrayref of fields to be validated, or a scalar value which matches (a validation profile or auto-validating method name). Whether and what the method returns is yours to decide. The method will return undefined if validation fails. The ensure keyword wraps and functions much in the same way as the method keyword.

The field keyword (or fld) registers a data validation rule for reuse and validation in code. The field name should correspond with the parameter name expected to be passed to your validation class or validated against.

package MyApp::Person;

use Validation::Class;

field 'username' => {
    required   => 1,
    min_length => 1,
    max_length => 255
};

The field keyword takes two arguments, the field name and a hashref of key/values pairs known as directives. For more information on pre-defined directives, please review the "list of core directives".

The field keyword also creates accessors which provide easy access to the field's corresponding parameter value(s). Accessors will be created using the field's name as a label having any special characters replaced with an underscore.

# accessor will be created as send_reminders
field 'send-reminders' => {
    length => 1
};

Please note that prefixing field names with a double plus-symbol instructs the register to merge your declaration with any pre-existing declarations within the same scope (e.g. fields imported via loading roles), whereas prefixing field names with a single plus-symbol instructs the register to overwrite any pre-existing declarations.

package MyApp::Person;

use Validation::Class;

set role => 'MyApp::User';

# append existing field and overwrite directives
field '++email_address' => {
    required => 1
};

# redefine existing field
field '+login' => {
    required => 1
};

1;

The filter keyword (or flt) registers custom filters to be used in your field definitions. It is a means of extending the pre-existing filters declared by the "filters directive" before instantiation.

package MyApp::Person;

use Validate::Class;

filter 'flatten' => sub {
    $_[0] =~ s/[\t\r\n]+/ /g;
    return $_[0];
};

field 'biography' => {
    filters => ['trim', 'strip', 'flatten']
};

1;

The filter keyword takes two arguments, the name of the filter and a coderef which will be used to filter the value the associated field. The coderef is passed the value of the field and that value MUST be operated on directly. The coderef should also return the transformed value.

The load keyword (or set), which can also be used as a class method, provides options for extending the current class by declaring roles, requirements, etc.

The process of applying roles, requirement, and other settings to the current class mainly involves introspecting the namespace's methods and merging relevant parts of the prototype configuration.

The `classes` (or class) option uses Module::Find to load all child classes (in-all-subdirectories) for convenient access through the "class" in Validation::Class::Prototype method, and when introspecting a larger application. This option accepts an arrayref or single argument.

package MyApp;

use Validation::Class;

load classes => ['MyApp::Domain1', 'MyApp::Domain2'];

package main;

my $app = MyApp->new;

my $person = $app->class('person'); # return a new MyApp::Person object

1;

package MyApp::User;

use Validate::Class;

load requirements => 'activate';

package MyApp::Person;

use Validation::Class;

load role => 'MyApp::User';

sub activate {}

1;

The `requirements` (or required) option is used to ensure that if/when the class is used as a role the calling class has specific pre-existing methods. This option accepts an arrayref or single argument.

package MyApp::User;

use Validate::Class;

load requirements => ['activate', 'deactivate'];

1;

package MyApp::Person;

use Validation::Class;

load role => 'MyApp::User';

1;

The `roles` (or role) option is used to load and inherit functionality from other validation classes. These classes should be used and thought-of as roles although they can also be fully-functioning validation classes. This option accepts an arrayref or single argument.

package MyApp::Person;

use Validation::Class;

load roles => ['MyApp::User', 'MyApp::Visitor'];

1;

The message keyword (or msg) registers a class-level error message template that will be used in place of the error message defined in the corresponding directive class if defined. Error messages can also be overridden at the individual field-level as well. See the Validation::Class::Directive::Messages for instructions on how to override error messages at the field-level.

package MyApp::Person;

use Validation::Class;

field email_address => {
    required   => 1,
    min_length => 3,
    messages   => {
        # field-level error message override
        min_length => '%s is not even close to being a valid email address'
    }
};

# class-level error message overrides
message required   => '%s is needed to proceed';
message min_length => '%s needs more characters';

1;

The message keyword takes two arguments, the name of the directive whose error message you wish to override and a string which will be used to as a template which is feed to sprintf to format the message.

The method keyword (or mth) is used to register an auto-validating method. Similar to method signatures, an auto-validating method can leverage pre-existing validation rules and profiles to ensure a method has the required pre/post-conditions and data necessary for execution.

package MyApp::Person;

use Validation::Class;

method 'register' => {

    input  => ['name', '+email', 'username', '+password', '+password2'],
    output => ['+id'], # optional output validation, dies on failure
    using  => sub {

        my ($self, @args) = @_;

        # do something registrationy
        $self->id(...); # set the ID field for output validation

        return $self;

    }

};

package main;

my $person = MyApp::Person->new(params => $params);

if ($person->register) {

    # handle the successful registration

}

1;

The method keyword takes two arguments, the name of the method to be created and a hashref of required key/value pairs. The hashref may have a `using` key whose value is the coderef to be executed upon successful validation. The `using` key is only optional when a pre-existing subroutine has the same name or the method being declared prefixed with a dash or dash-process-dash. The following are valid subroutine names to be called by the method declaration in absence of a `using` key. Please note, unlike the ensure keyword, any pre-existing subroutines will not be wrapped-and-replaced and can be executed without validation if called directly.

sub _name {
    ...
}

sub _process_name {
    ...
}

The hashref may have an input key (e.g. input, input_document, input_profile, or input_method). The `input` key (specifically) must have a value which must be either an arrayref of fields to be validated, or a scalar value which matches (a validation profile or auto-validating method name), which will be used to perform data validation before the aforementioned coderef has been executed. Whether and what the method returns is yours to decide. The method will return undefined if validation fails.

# alternate usage

method 'registration' => {
    input  => ['name', '+email', 'username', '+password', '+password2'],
    output => ['+id'], # optional output validation, dies on failure
};

sub _process_registration {
    my ($self, @args) = @_;
        $self->id(...); # set the ID field for output validation
    return $self;
}

Optionally the hashref may also have an output key (e.g. output, output_document, output_profile, or output_method). The `output` key (specifically) must have a value which must be either an arrayref of fields to be validated, or a scalar value which matches (a validation profile or auto-validating method name), which will be used to perform data validation after the aforementioned coderef has been executed.

Please note that output validation failure will cause the program to die, the premise behind this decision is based on the assumption that given successfully validated input a routine's output should be predictable and if an error occurs it is most-likely a program error as opposed to a user error.

See the ignore_failure and report_failure attributes on the prototype to control how method validation failures are handled.

The mixin keyword (or mxn) registers a validation rule template that can be applied (or "mixed-in") to any field by specifying the mixin directive. Mixin directives are processed first so existing field directives will override any directives created by the mixin directive.

package MyApp::Person;

use Validation::Class;

mixin 'boilerplate' => {
    required   => 1,
    min_length => 1,
    max_length => 255
};

field 'username' => {
    # min_length, max_length, .. required will be overridden
    mixin    => 'boilerplate',
    required => 0
};

Since version 7.900015, all classes are automatically configured with the following default mixins for the sake of convenience:

mixin ':flg' => {
    required   => 1,
    min_length => 1,
    filters    => [qw/trim strip numeric/],
    between    => [0, 1]
};

mixin ':num' => {
    required   => 1,
    min_length => 1,
    filters    => [qw/trim strip numeric/]
};

mixin ':str' => {
    required   => 1,
    min_length => 1,
    filters    => [qw/trim strip/]
};

Please note that the aforementioned mixin names are prefixed with a semi-colon but are treated as an exception to the rule. Prefixing mixin names with a double plus-symbol instructs the register to merge your declaration with any pre-existing declarations within the same scope (e.g. mixins imported via loading roles), whereas prefixing mixin names with a single plus-symbol instructs the register to overwrite any pre-existing declarations.

package MyApp::Moderator;

use Validation::Class;

set role => 'MyApp::Person';

# overwrite and append existing mixin
mixin '++boilerplate' => {
    min_symbols => 1
};

# redefine existing mixin
mixin '+username' => {
    required => 1
};

1;

The mixin keyword takes two arguments, the mixin name and a hashref of key/values pairs known as directives.

The profile keyword (or pro) registers a validation profile (coderef) which as in the traditional use of the term is a sequence of validation routines that validates data relevant to a specific action.

package MyApp::Person;

use Validation::Class;

profile 'check_email' => sub {

    my ($self, @args) = @_;

    if ($self->email_exists) {
        my $email = $self->fields->get('email');
        $email->errors->add('Email already exists');
        return 0;
    }

    return 1;

};

package main;

my $user = MyApp::Person->new(params => $params);

unless ($user->validate_profile('check_email')) {
    # handle failures
}

1;

The profile keyword takes two arguments, a profile name and coderef which will be used to execute a sequence of actions for validation purposes.

The new method instantiates a new class object, it performs a series of actions (magic) required for the class to function properly, and for that reason, this method should never be overridden. Use the build keyword for hooking into the instantiation process.

In the event a foreign (pre-existing) `new` method is detected, an `initialize_validator` method will be injected into the class containing the code (magic) necessary to normalize your environment.

package MyApp::Person;

use Validation::Class;

# hook
build sub {

    my ($self, @args) = @_; # on instantiation

};

sub new {

    # rolled my own
    my $self = bless {}, shift;

    # execute magic
    $self->initialize_validator;

}

1;

The prototype method (or proto) returns an instance of the associated class prototype. The class prototype is responsible for manipulating and validating the data model (the class). It is not likely that you'll need to access this method directly, see Validation::Class::Prototype.

package MyApp::Person;

use Validation::Class;

package main;

my $person = MyApp::Person->new;

my $prototype = $person->prototype;

1;

Validation::Class mostly provides sugar functions for modeling your data validation requirements. Each class you create is associated with a prototype class which provides the data validation engine and keeps your class namespace free from pollution, please see Validation::Class::Prototype for more information on specific methods and attributes. Validation::Class injects a few proxy methods into your class which are basically aliases to the corresponding prototype class methods, however it is possible to access the prototype directly using the proto/prototype methods.

$self->class;

See "class" in Validation::Class::Prototype for full documentation.

$self->clear_queue;

See "clear_queue" in Validation::Class::Prototype for full documentation.

$self->error_count;

See "error_count" in Validation::Class::Prototype for full documentation.

$self->error_fields;

See "error_fields" in Validation::Class::Prototype for full documentation.

$self->errors;

See "errors" in Validation::Class::Prototype for full documentation.

$self->errors_to_string;

See "errors_to_string" in Validation::Class::Prototype for full documentation.

$self->get_errors;

See "get_errors" in Validation::Class::Prototype for full documentation.

$self->get_fields;

See "get_fields" in Validation::Class::Prototype for full documentation.

$self->get_hash;

See "get_hash" in Validation::Class::Prototype for full documentation.

$self->get_params;

See "get_params" in Validation::Class::Prototype for full documentation.

$self->get_values;

See "get_values" in Validation::Class::Prototype for full documentation.

$self->fields;

See "fields" in Validation::Class::Prototype for full documentation.

$self->filtering;

See "filtering" in Validation::Class::Prototype for full documentation.

$self->ignore_failure;

See "ignore_failure" in Validation::Class::Prototype for full documentation.

$self->ignore_intervention;

See "ignore_intervention" in Validation::Class::Prototype for full documentation.

$self->ignore_unknown;

See "ignore_unknown" in Validation::Class::Prototype for full documentation.

$self->is_valid;

See "is_valid" in Validation::Class::Prototype for full documentation.

$self->param;

See "param" in Validation::Class::Prototype for full documentation.

$self->params;

See "params" in Validation::Class::Prototype for full documentation.

$self->plugin;

See "plugin" in Validation::Class::Prototype for full documentation.

$self->queue;

See "queue" in Validation::Class::Prototype for full documentation.

$self->report_failure;

See "report_failure" in Validation::Class::Prototype for full documentation.

$self->report_unknown;

See "report_unknown" in Validation::Class::Prototype for full documentation.

$self->reset_errors;

See "reset_errors" in Validation::Class::Prototype for full documentation.

$self->reset_fields;

See "reset_fields" in Validation::Class::Prototype for full documentation.

$self->reset_params;

See "reset_params" in Validation::Class::Prototype for full documentation.

$self->set_errors;

See "set_errors" in Validation::Class::Prototype for full documentation.

$self->set_fields;

See "set_fields" in Validation::Class::Prototype for full documentation.

$self->set_params;

See "set_params" in Validation::Class::Prototype for full documentation.

$self->set_method;

See "set_method" in Validation::Class::Prototype for full documentation.

$self->stash;

See "stash" in Validation::Class::Prototype for full documentation.

$self->validate;

See "validate" in Validation::Class::Prototype for full documentation.

$self->validate_document;

See "validate_document" in Validation::Class::Prototype for full documentation.

$self->validate_method;

See "validate_method" in Validation::Class::Prototype for full documentation.

$self->validate_profile;

See "validate_profile" in Validation::Class::Prototype for full documentation.

Validation::Class is stable, its feature-set is complete, and is currently in maintenance-only mode, i.e. Validation::Class will only be updated with minor enhancements and bug fixes. However, the lessons learned will be incorporated into a compelete rewrite uploaded under the namespace Validation::Interface. The Validation::Interface fork is designed to have a much simpler API with less options and better execution, focused on validating hierarchical data as its primarily objective.

Validation::Class does NOT provide method modifiers but can be easily extended with Class::Method::Modifiers.

before foo => sub { ... };

See "before method(s) => sub { ... }" in Class::Method::Modifiers for full documentation.

around foo => sub { ... };

See "around method(s) => sub { ... }" in Class::Method::Modifiers for full documentation.

after foo => sub { ... };

See "after method(s) => sub { ... }" in Class::Method::Modifiers for full documentation.

Validation::Class does not validate blessed objects. If you need a means for validating object types you should use a modern object system like Moo, Mouse, or Moose. Alternatively, you could use decoupled object validators like Type::Tiny, Params::Validate or Specio.

Al Newkirk [email protected]

This software is copyright (c) 2011 by Al Newkirk.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.