NAME
Validation::Class - Powerful Data Validation Framework
VERSION
version 7.900004
SYNOPSIS
package MyApp::Person;
use Validation::Class;
# a data validation template
mixin basic => {
required => 1,
max_length => 255,
filters => [qw/trim strip/]
};
# data validation rules for the login parameter
field login => {
mixin => 'basic',
min_length => 5
};
# data validation rules for the password parameter
field password => {
mixin => 'basic',
min_length => 5,
min_symbols => 1
};
# ... elsewhere in your application
my $person = MyApp::Person->new(login => 'admin', password => 'secr3t');
unless ($person->validates) {
# handle the failures
}
1;
DESCRIPTION
Validation::Class is a robust data validation framework which aims
provide an extensible framework for developing clean yet sophisticated
data validation objects. 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).
QUICKSTART
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.
RATIONALE
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.
KEYWORDS
attribute
The attribute keyword (or has) registers a class attribute. This is only
a minimalistic variant of what you may have encountered in other object
systems.
package MyApp::Person;
use Validate::Class;
attribute 'first_name' => 'Peter';
attribute 'last_name' => 'Venkman';
attribute 'full_name' => sub {
my ($self) = @_;
return join ', ', $self->last_name, $self->first_name;
};
1;
The attribute keyword takes two arguments, the attribute name and a
constant or coderef that will be used as its default value.
build
The build keyword (or bld) registers a coderef to be run at
instantiation much in the same way the common BUILD routine is used in
modern OO frameworks.
package MyApp::Person;
use Validation::Class;
build sub {
my ($self, $args) = @_;
# run after instantiation in the order declared
};
The build keyword takes one argument, a coderef which is passed the
instantiated class object.
directive
The directive keyword (or dir) registers custom validator directives to
be used in your field definitions. It is a means of extending the core
field directives before instantiation. Please see
Validation::Class::Directive for insight into creating your own
installable directives.
package MyApp::Directives;
use Validation::Class 'directive';
use Data::Validate::Email;
directive 'isa_email_address' => sub {
my ($self, $proto, $field, $param) = @_;
my $validator = Data::Validate::Email->new;
unless ($validator->is_email($param)) {
my $handle = $field->label || $field->name;
$field->errors->add("$handle must be a valid email address");
return 0;
}
return 1;
};
package MyApp::Person;
use Validate::Class;
use MyApp::Directives;
field 'email_address' => {
isa_email_address => 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.
field
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.
package MyApp::Person;
use Validation::Class;
field 'login' => {
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.
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
};
Protip: Field directives are used to validate scalar and array data.
Don't use fields to store and validate objects. Please see the *has*
keyword instead or use an object system with type constraints like
Moose.
filter
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 Validation::Class::Directive::Filters before
instantiation.
package MyApp::Directives;
use Validation::Class;
filter 'flatten' => sub {
$_[0] =~ s/[\t\r\n]+/ /g;
return $_[0];
};
package MyApp::Person;
use Validate::Class;
use MyApp::Directives;
field 'biography' => {
filters => ['trim', '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.
load
The load keyword (or set), which can also be used as a class method,
provides options for extending the current class by declaring roles,
plugins, etc.
The process of applying roles to the current class mainly involves
copying the subject's methods and prototype configuration.
package MyApp::Person;
use Validation::Class;
load role => 'MyApp::User';
1;
The `classes` (or class) option, can be a constant or arrayref and uses
Module::Find to load all child classes (in-all-subdirectories) for
convenient access through the "class" in Validation::Class::Prototype
method.
Existing parameters and configuration options are passed to the child
class constructor. All attributes can be easily overwritten using the
attribute's accessors on the child class. These child classes are often
referred to as relatives. This option accepts a constant or an arrayref
of constants.
package MyApp;
use Validation::Class;
# load all child classes
load classes => [__PACKAGE__];
package main;
my $app = MyApp->new;
my $person = $app->class('person'); # return a new MyApp::Person object
1;
The `roles` (or role) option is used to load and inherit functionality
from other validation classes. These classes should be used and
thought-of as roles although they can also be fully-functioning
validation classes. This option accepts a constant or an arrayref of
constants.
package MyApp::Person;
use Validation::Class;
load roles => ['MyApp::User', 'MyApp::Visitor'];
1;
message
The message keyword (or msg) registers a class-level error message
template that will be used in place of the error message defined in the
corresponding directive class if defined. Error messages can also be
overriden at the individual field-level as well. See the
Validation::Class::Directive::Messages for instructions on how to
override error messages at the field-level.
package MyApp::Person;
use Validation::Class;
field email_address => {
required => 1,
min_length => 3,
messages => {
# field-level error message override
min_length => '%s is not even close to being a valid email address'
}
};
# class-level error message overrides
message required => '%s is needed to proceed';
message min_length => '%s needs more characters';
1;
The message keyword takes two arguments, the name of the directive whose
error message you wish to override and a string which will be used to as
a template which is feed to sprintf to format the message.
method
The method keyword (or mth) is used to register an auto-validating
method. Similar to method signatures, an auto-validating method can
leverage pre-existing validation rules and profiles to ensure a method
has the required data necessary for execution.
package MyApp::Person;
use Validation::Class;
method 'register' => {
input => ['name', '+email', 'login', '+password', '+password2'],
output => ['+id'], # optional output validation, dies on failure
using => sub {
my ($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 must have
an `input` key whose value is either an arrayref of fields to be
validated, or a constant value which matches a validation profile name.
The hashref must also have a `using` key whose value is a coderef which
will be executed upon successfully validating the input. Whether and
what the method returns is yours to decide.
Optionally the required hashref can have an `output` key whose value is
either an arrayref of fields to be validated, or a constant value which
matches a validation profile 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 switch to control how method
input validation failures are handled.
mixin
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
};
# min_length, max_length, but not required
field 'login' => {
mixin => 'boilerplate',
required => 0
};
The mixin keyword takes two arguments, the mixin name and a hashref of
key/values pairs known as directives.
profile
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
}
The profile keyword takes two arguments, a profile name and coderef
which will be used to execute a sequence of actions for validation
purposes.
METHODS
new
The new method instantiates a new class object, it performs a series of
actions (magic) required for the class 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 `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;
}
prototype
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;
PROXY METHODS
class
$self->class;
See "class" in Validation::Class::Prototype for full documentation.
clear_queue
$self->clear_queue;
See "clear_queue" in Validation::Class::Prototype for full
documentation.
error_count
$self->error_count;
See "error_count" in Validation::Class::Prototype for full
documentation.
error_fields
$self->error_fields;
See "error_fields" in Validation::Class::Prototype for full
documentation.
errors
$self->errors;
See "errors" in Validation::Class::Prototype for full documentation.
head2 errors_to_string
$self->errors_to_string;
See "errors_to_string" in Validation::Class::Prototype for full
documentation.
get_errors
$self->get_errors;
See "get_errors" in Validation::Class::Prototype for full documentation.
get_fields
$self->get_fields;
See "get_fields" in Validation::Class::Prototype for full documentation.
get_params
$self->get_params;
See "get_params" in Validation::Class::Prototype for full documentation.
fields
$self->fields;
See "fields" in Validation::Class::Prototype for full documentation.
filtering
$self->filtering;
See "filtering" in Validation::Class::Prototype for full documentation.
ignore_failure
$self->ignore_failure;
See "ignore_failure" in Validation::Class::Prototype for full
documentation.
ignore_unknown
$self->ignore_unknown;
See "ignore_unknown" in Validation::Class::Prototype for full
documentation.
param
$self->param;
See "param" in Validation::Class::Prototype for full documentation.
params
$self->params;
See "params" in Validation::Class::Prototype for full documentation.
queue
$self->queue;
See "queue" in Validation::Class::Prototype for full documentation.
report_failure
$self->report_failure;
See "report_failure" in Validation::Class::Prototype for full
documentation.
report_unknown
$self->report_unknown;
See "report_unknown" in Validation::Class::Prototype for full
documentation.
reset_errors
$self->reset_errors;
See "reset_errors" in Validation::Class::Prototype for full
documentation.
reset_fields
$self->reset_fields;
See "reset_fields" in Validation::Class::Prototype for full
documentation.
reset_params
$self->reset_params;
See "reset_params" in Validation::Class::Prototype for full
documentation.
set_errors
$self->set_errors;
See "set_errors" in Validation::Class::Prototype for full documentation.
set_fields
$self->set_fields;
See "set_fields" in Validation::Class::Prototype for full documentation.
set_params
$self->set_params;
See "set_params" in Validation::Class::Prototype for full documentation.
set_method
$self->set_method;
See "set_method" in Validation::Class::Prototype for full documentation.
stash
$self->stash;
See "stash" in Validation::Class::Prototype for full documentation.
validate
$self->validate;
See "validate" in Validation::Class::Prototype for full documentation.
validate_method
$self->validate_method;
See "validate_method" in Validation::Class::Prototype for full
documentation.
validate_profile
$self->validate_profile;
See "validate_profile" in Validation::Class::Prototype for full
documentation.
VALIDATE BY PROXY
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.
EXTENDING VALIDATION::CLASS
Validation::Class does NOT provide method modifiers but can be easily
extended with Class::Method::Modifiers.
before
before foo => sub { ... };
See "before method(s) => sub { ... }" in Class::Method::Modifiers for
full documentation.
around
around foo => sub { ... };
See "around method(s) => sub { ... }" in Class::Method::Modifiers for
full documentation.
after
after foo => sub { ... };
See "after method(s) => sub { ... }" in Class::Method::Modifiers for
full documentation.
SEE ALSO
If you have simple data validation needs, please review:
Validation::Class::Simple
Additionally you may want to look elsewhere for your data validation
needs so the following is a list of other validation
libraries/frameworks you might be interested in. If I've missed a really
cool new validation library please let me know.
HTML::FormHandler
This library seems to be the defacto standard for designing Moose
classes with HTML-centric data validation rules.
Data::Verifier
This library is a great approach towards adding robust validation
logic to your existing Moose-based codebase.
Validate::Tiny
This library is nice for simple use-cases, it has virtually no
dependencies and solid test coverage.
AUTHOR
Al Newkirk <anewkirk@ana.io>
COPYRIGHT AND LICENSE
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.