NAME
Dancer2::Plugin::FormValidator - neat and easy to start form validation plugin for Dancer2.
VERSION
version 0.90
SYNOPSIS
### If you need a simple and easy validation in your project,
### then this module is what you need.
use Dancer2;
use Dancer2::Plugin::FormValidator;
### First create form validation profile class.
package RegisterForm {
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::Profile';
### Here you need to declare fields => validators.
sub profile {
return {
username => [ qw(required alpha_num length_min:4 length_max:32) ],
email => [ qw(required email length_max:127) ],
password => [ qw(required length_max:40) ],
password_cnf => [ qw(required same:password) ],
confirm => [ qw(required accepted) ],
};
}
}
### Now you can use it in your Dancer2 project.
post '/form' => sub {
if (validate profile => RegisterForm->new) {
my $valid_hash_ref = validated;
save_user_input($valid_hash_ref);
redirect '/success_page';
}
redirect '/form';
};The html result could be like:
DESCRIPTION
This is micro-framework that provides validation in your Dancer2 application. It consists of dsl's keywords: validate, validated, errors. It has a set of built-in validators that can be extended by compatible modules (extensions). Also proved runtime switching between languages, so you can show proper error messages to users.
This module has a minimal set of dependencies and does not require the mandatory use of DBIc or Moose.
Uses simple and declarative approach to validate forms.
Validator
First, you need to create class which will implements at least one main role: Dancer2::Plugin::FormValidator::Role::Profile.
This role requires profile method which should return a HashRef Data::FormValidator accepts:
package RegisterForm
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::Profile';
sub profile {
return {
username => [ qw(required alpha_num_ascii length_min:4 length_max:32) ],
email => [ qw(required email length_max:127) ],
password => [ qw(required length_max:40) ],
password_cnf => [ qw(required same:password) ],
confirm => [ qw(required accepted) ],
};
};Profile method
Profile method should always return a HashRef[ArrayRef] where keys are input fields names and values are ArrayRef with list of validators.
Application
Then you need to set basic configuration:
use Dancer2;
set plugins => {
FormValidator => {
session => {
namespace => '_form_validator' # This is required field
},
},
};Now you can validate POST parameters in your controller:
use Dancer2;
use Dancer2::Plugin::FormValidator;
use RegisterForm;
post '/register' => sub {
if (my $valid_hash_ref = validate profile => RegisterForm->new) {
if (login($valid_hash_ref)) {
redirect '/success_page';
}
}
redirect '/register';
};
get '/register' => sub {
template 'app/register' => {
title => 'Register page',
};
};Template
In you template you have access to: $errors - this is HashRef[ArrayRef] with fields names as keys and error messages values and $old - contains old input values.
Template app/register:
<div class="w-3/4 max-w-md bg-white shadow-lg py-4 px-6">
<form method="post" action="/register">
<div class="py-2">
<label class="block font-normal text-gray-400" for="name">
Name
</label>
<input
type="text"
id="name"
name="name"
value="<: $old[name] :>"
class="border border-2 w-full h-5 px-4 py-5 mt-1 rounded-md
hover:outline-none focus:outline-none focus:ring-1 focus:ring-indigo-100"
>
<: for $errors[name] -> $error { :>
<small class="pl-1 text-red-400"><: $error :></small>
<: } :>
</div>
<div class="py-2">
<label class="block font-normal text-gray-400" for="email">
Name
</label>
<input
type="text"
id="email"
name="email"
value="<: $old[email] :>"
class="border border-2 w-full h-5 px-4 py-5 mt-1 rounded-md
hover:outline-none focus:outline-none focus:ring-1 focus:ring-indigo-100"
>
<: for $errors[email] -> $error { :>
<small class="pl-1 text-red-400"><: $error :></small>
<: } :>
<!-- Other fields -->
...
...
...
<!-- Other fields end -->
</div>
<button
type="submit"
class="mt-4 bg-sky-600 text-white py-2 px-6 rounded-md hover:bg-sky-700"
>
Register
</button>
</form>
</div>CONFIGURATION
...
plugins:
FormValidator:
session:
namespace: '_form_validator' # this is required
messages:
language: en # this is default
ucfirst: 1 # this is default
validators:
required:
en: %s is needed from config # custom en message
de: %s ist erforderlich # custom de message
...
extensions:
dbic:
provider: Dancer2::Plugin::FormValidator::Extension::DBIC
...
...session
namespace
Session storage key where this module stores data, like: errors or old vars.
messages
language
Default language for error messages.
ucfirst
Apply ucfirst function to messages or not.
validators
Key => values, where key is validator name and value is messages dictionary for different languages.
extensions
Key => values, where key is extension short name and values is its configuration.
DSL KEYWORDS
validate
validate(Hash $params): HashRef|undefAccept arguments as hash:
(
profile => Object implementing Dancer2::Plugin::FormValidator::Role::Profile # required
input => HashRef of values to validate, default is body_parameters->as_hashref_mixed
lang => Accepts two-lettered language id, default is 'en'
)Profile is required, input and lang is optional.
Returns valid input HashRef if validation succeed, otherwise returns undef.
### You can use HashRef returned from validate.
if (my $valid_hash_ref = validate profile => RegisterForm->new) {
# Success, data is valid.
}
### Or more declarative approach with validated keyword.
if (validate profile => RegisterForm->new) {
# Success, data is valid.
my $valid_hash_ref = validated;
# Do some operations...
}
else {
# Error, data is invalid.
my $errors = errors; # errors keyword returns error messages.
# Redirect or show errors...
}validated
validated(): HashRef|undefNo arguments. Returns valid input HashRef if validate succeed. Undef value will be returned after first call within one validation process.
my $valid_hash_ref = validated;errors
errors(): HashRefNo arguments. Returns HashRef[ArrayRef] if validation failed.
my $errors_hash_multi = errors;Validators
accepted
accepted(): BoolValidates that field exists and one of the listed: (yes on 1).
field => [ qw(accepted) ]alpha
alpha(String $encoding = 'a'): BoolValidate that string only contain of alphabetic symbols. By default encoding is ascii, i.e /^[[:alpha:]]+$/a.
field => [ qw(alpha) ]To set encoding to unicode you need to pass 'u' argument:
field => [ qw(alpha:u) ]Then the validation rule will be /^[[:alpha:]]+$/.
alpha_num
alpha_num(String $encoding = 'a'): BoolValidate that string only contain of alphabetic symbols, underscore and numbers 0-9. By default encoding is ascii, i.e. /^\w+$/a.
field => [ qw(alpha_num) ]To set encoding to unicode you need to pass 'u' argument:
field => [ qw(alpha_num:u) ]Rule will be /^\w+$/.
email(): BoolValidate that field is valid email(rfc822).
field => [ qw(email) ]email_dns
email_dns(): BoolValidate that field is valid email(rfc822) and dns exists.
field => [ qw(email_dns) ]enum
enum(Array @values): BoolValidate that field is one of listed values.
field => [ qw(enum:value1,value2) ]integer
integer(): BoolValidate that field is integer.
field => [ qw(integer) ]length_max
length_max(Int $num): BoolValidate that string length <= num.
field => [ qw(length_max:32) ]length_min
length_min(Int $num): BoolValidate that string length >= num.
field => [ qw(length_max:4) ]max
max(Int $num): BoolValidate that field is number <= num.
field => [ qw(max:32) ]min
min(Int $num): BoolValidate that field is number >= num.
field => [ qw(min:4) ]numeric
numeric(): BoolValidate that field is number.
field => [ qw(numeric) ]required
required(): BoolValidate that field exists and not empty string.
field => [ qw(required) ]same
same(String $field_name): boolValidate that field is exact value as another.
field_1 => [ qw(required) ]
field_2 => [ qw(required same:field_1) ]CUSTOM MESSAGES
To define custom error messages for fields/validators your Validator should implement Role: Dancer2::Plugin::FormValidator::Role::ProfileHasMessages.
package Validator {
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::ProfileHasMessages';
sub profile {
return {
name => [qw(required)],
email => [qw(required email)],
};
}
sub messages {
return {
name => {
required => {
en => 'Specify your %s',
},
},
email => {
required => {
en => '%s is needed',
},
email => {
en => '%s please use valid email',
}
}
};
}
}EXTENSIONS
Writing custom extensions
You can extend the set of validators by writing extensions:
package Extension {
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::Extension';
sub validators {
return {
is_true => 'IsTrue', # Full class name
email => 'Email', # Full class name
restrict => 'Restrict', # Full class name
}
}
}Extension should implement Role: Dancer2::Plugin::FormValidator::Role::Extension.
Hint: you could reassign built-in validator with your custom one.
Custom validators:
package IsTrue {
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::Validator';
sub message {
return {
en => '%s is not a true value',
};
}
sub validate {
my ($self, $field, $input) = @_;
if (exists $input->{$field}) {
if ($input->{$field} == 1) {
return 1;
}
else {
return 0;
}
}
return 1;
}
}Validator should implement Role: Dancer2::Plugin::FormValidator::Role::Validator.
Config:
set plugins => {
FormValidator => {
session => {
namespace => '_form_validator'
},
extensions => {
extension => {
provider => 'Extension',
}
}
},
};Extensions modules
There is a set of ready-made extensions available on cpan:
Dancer2::Plugin::FormValidator::Extension::Password - for validating passwords.
Dancer2::Plugin::FormValidator::Extension::DBIC - for checking fields existence in table rows.
ROLES
Dancer2::Plugin::FormValidator::Role::Profile - for profile classes.
Dancer2::Plugin::FormValidator::Role::HasMessages - for classes, that implements custom error messages.
Dancer2::Plugin::FormValidator::Role::ProfileHasMessages - brings together Profile and HasMassages.
Dancer2::Plugin::FormValidator::Role::Extension - for extension classes.
Dancer2::Plugin::FormValidator::Role::Validator - for custom validators.
HINTS
If you don't want to create separated classes for your validation logic, you could create one base class and reuse it in your project.
### Validator class
package Validator {
use Moo;
with 'Dancer2::Plugin::FormValidator::Role::Profile';
has profile_hash => (
is => 'ro',
required => 1,
);
sub profile {
return $_[0]->profile_hash;
}
}
### Application
use Dancer2
my $validator = Validator->new(profile_hash =>
{
email => [qw(required email)],
}
);
post '/subscribe' => sub {
if (not validate profile => $validator) {
to_json errors;
}
};BUGS AND LIMITATIONS
If you find one, please let me know.
SOURCE CODE REPOSITORY
https://github.com/AlexP007/dancer2-plugin-formvalidator.
AUTHOR
Alexander Panteleev <alexpan at cpan dot org>.
LICENSE AND COPYRIGHT
This software is copyright (c) 2022 by Alexander Panteleev. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.