Dancer2::Plugin::FormValidator - neat and easy to start form validation plugin for Dancer2.
version 1.02
### If you need a simple and easy validation in your project, ### 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:
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.
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 should always return a HashRef[ArrayRef] where keys are input fields names and values are ArrayRef with list of validators.
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', }; };
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"> Email </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>
... 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 storage key where this module stores data, like: errors or old vars.
Default language for error messages.
Apply ucfirst function to messages or not.
Key => values, where key is validator name and value is messages dictionary for different languages.
Key => values, where key is extension short name and values is its configuration.
validate(Hash %args): HashRef|undef
Accept 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(): HashRef|undef
No 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(): HashRef
No arguments. Returns HashRef[ArrayRef] if validation failed.
my $errors_hash_multi = errors;
accepted(): Bool
Validates that field exists and one of the listed: (yes on 1).
field => [ qw(accepted) ]
alpha(Str $encoding = 'a'): Bool
Validate that string only contain of alphabetic symbols. By default encoding is ascii, i.e /^[[:alpha:]]+$/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(Str $encoding = 'a'): Bool
Validate that string only contain of alphabetic symbols, underscore and numbers 0-9. By default encoding is ascii, i.e. /^\w+$/a.
field => [ qw(alpha_num) ]
field => [ qw(alpha_num:u) ]
Rule will be /^\w+$/.
boolean(): Bool
Validate that field is 0 or 1 scalar value.
field => [ qw(boolean) ]
email(): Bool
Validate that field is valid email(rfc822).
field => [ qw(email) ]
email_dns(): Bool
Validate that field is valid email(rfc822) and dns exists.
field => [ qw(email_dns) ]
enum(Array @values): Bool
Validate that field is one of listed values.
field => [ qw(enum:value1,value2) ]
integer(): Bool
Validate that field is integer.
field => [ qw(integer) ]
length_max(Int $num): Bool
Validate that string length <= num.
field => [ qw(length_max:32) ]
length_min(Int $num): Bool
Validate that string length >= num.
field => [ qw(length_max:4) ]
max(Int $num): Bool
Validate that field is number <= num.
field => [ qw(max:32) ]
min(Int $num): Bool
Validate that field is number >= num.
field => [ qw(min:4) ]
numeric(): Bool
Validate that field is number.
field => [ qw(numeric) ]
required(): Bool
Validate that field exists and not empty string.
field => [ qw(required) ]
required_with(Str $field_name): Bool
Validate that field exists and not empty string if another field is exists and not empty.
field_1 => [ qw(required) ] field_2 => [ qw(required_with:field_1) ]
same(Str $field_name): Bool
Validate that field is exact value as another.
field_1 => [ qw(required) ] field_2 => [ qw(required same:field_1) ]
To define custom error messages for fields/validators your Validator should implement Role: Dancer2::Plugin::FormValidator::Role::ProfileHasMessages.
package Validator { use Moo; with 'Dancer2::Plugin::FormValidator::Role::ProfileHasMessages'; sub profile { return { name => [qw(required)], email => [qw(required email)], }; } sub messages { return { name => { required => { en => 'Specify your %s', }, }, email => { required => { en => '%s is needed', }, email => { en => '%s please use valid email', } } }; } }
There is hook_before method available, which allows your Profile object to make decisions depending on the input data. You could use it with Moo around modifier:
around hook_before => sub { my ($orig, $self, $profile, $input) = @_; # If there is specific input value. if ($input->{name} eq 'Secret') { # Delete all validators for field 'surname'. delete $profile->{surname}; } return $orig->($self, $profile, $input); };
You can extend the set of validators by writing extensions:
package Extension { use Moo; with 'Dancer2::Plugin::FormValidator::Role::Extension'; sub validators { return { is_true => 'IsTrue', # Full class name email => 'Email', # Full class name restrict => 'Restrict', # Full class name } } }
Extension should implement Role: Dancer2::Plugin::FormValidator::Role::Extension.
Hint: you could reassign built-in validator with your custom one.
Custom validators:
package IsTrue { use Moo; with 'Dancer2::Plugin::FormValidator::Role::Validator'; sub message { return { en => '%s is not a true value', }; } sub validate { my ($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', } } }, };
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.
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.
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; } };
If you find one, please let me know.
https://github.com/AlexP007/dancer2-plugin-formvalidator.
Alexander Panteleev <alexpan at cpan dot org>.
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.
To install Dancer2::Plugin::FormValidator, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Dancer2::Plugin::FormValidator
CPAN shell
perl -MCPAN -e shell install Dancer2::Plugin::FormValidator
For more information on module installation, please visit the detailed CPAN module installation guide.