NAME
HTML::FormHandler - form handler written in Moose
SYNOPSIS
Note: This package no longer includes the DBIC model. If you intend to use HTML::FormHandler::Model::DBIC, please install that package separately.
An example of a form class:
package MyApp::Form::User;
use HTML::FormHandler::Moose;
extends 'HTML::FormHandler::Model::DBIC';
has '+item_class' => ( default => 'User' );
has_field 'name' => ( type => 'Text' );
has_field 'age' => ( type => 'PosInteger', apply => [ 'MinimumAge' ] );
has_field 'birthdate' => ( type => 'DateTime' );
has_field 'hobbies' => ( type => 'Multiple' );
has_field 'address' => ( type => 'Text' );
has_field 'city' => ( type => 'Text' );
has_field 'state' => ( type => 'Select' );
has_field 'email' => ( type => 'Email' );
has '+dependency' => ( default => sub {
[ ['address', 'city', 'state'], ]
}
);
subtype 'MinimumAge'
=> as 'Int'
=> where { $_ > 13 }
=> message { "You are not old enough to register" };
no HTML::FormHandler::Moose;
1;An example of a Catalyst controller that uses an HTML::FormHandler form to update a 'Book' record:
package MyApp::Controller::Book;
BEGIN {
use Moose;
extends 'Catalyst::Controller';
}
use MyApp::Form::Book;
sub book_base : Chained PathPart('book') CaptureArgs(0)
{
my ( $self, $c ) = @_;
# setup
}
sub item : Chained('book_base') PathPart('') CaptureArgs(1)
{
my ( $self, $c, $book_id ) = @_;
$c->stash( book => $c->model('DB::Book')->find($book_id) );
}
sub edit : Chained('item') PathPart('edit') Args(0)
{
my ( $self, $c ) = @_;
my $form = MyApp::Form::Book->new;
$c->stash( form => $form, template => 'book/form.tt' );
return unless $form->process( item => $c->stash->{book},
params => $c->req->parameters );
$c->res->redirect( $c->uri_for('list') );
}The example above creates the form dynamically on each request. You can also use a Moose attribute for the form.
has 'form' => ( isa => 'MyApp::Form::Book', is => 'ro',
default => sub { MyApp::Form::Book->new } );A dynamic form may be created in a controller using the field_list attribute to set fields:
my $form = HTML::FormHandler->new(
item => $user,
field_list => [
first_name => 'Text',
last_name => 'Text'
],
);DESCRIPTION
HTML::FormHandler allows you to define HTML form fields and validators. It can be used for both database and non-database forms, and will automatically update or create rows in a database. It can also be used to process structured data that doesn't come from an HTML form.
One of its goals is to keep the controller interface as simple as possible, and to minimize the duplication of code. In most cases, interfacing your controller to your form is only a few lines of code.
With FormHandler you'll never spend hours trying to figure out how to make a simple HTML change that would take one minute by hand. Because you CAN do it by hand. Or you can automate HTML generation as much as you want, with template widgets or pure Perl rendering classes, and stay completely in control of what, where, and how much is done automatically.
You can split the pieces of your forms up into logical parts and compose complete forms from FormHandler classes, roles, fields, collections of validations, transformations and Moose type constraints. You can write custom methods to process forms, add any attribute you like, use Moose method modifiers. FormHandler forms are Perl classes, so there's a lot of flexibility in what you can do.
HTML::FormHandler does not (yet) provide a complex HTML generating facility, but a simple, straightforward rendering role is provided by HTML::FormHandler::Render::Simple, which will output HTML formatted strings for a field or a form. HTML::FormHandler::Render::Table will display the form using an HTML table layout. There are also sample Template Toolkit widget files, documented at HTML::FormHandler::Manual::Templates.
The typical application for FormHandler would be in a Catalyst, DBIx::Class, Template Toolkit web application, but use is not limited to that. FormHandler can be used in any Perl application.
More Formhandler documentation and a tutorial can be found in the manual at HTML::FormHandler::Manual.
ATTRIBUTES and METHODS
Creating a form with 'new'
The new constructor takes name/value pairs:
MyForm->new(
item => $item,
init_object => { name => 'Your name here', username => 'choose' }
);No attributes are required on new. The form's fields will be built from the form definitions. If no initial data object has been provided, the form will be empty. Most attributes can be set on either 'new' or 'process'. The common attributes to be passed in to the constructor for a database form are either item_id and schema or item:
item_id - database row primary key
item - database row object
schema - (for DBIC) the DBIx::Class schemaThe following are occasionally passed in, but are more often set in the form class:
item_class - source name of row
dependency - (see dependency)
field_list - and array of field definitions
init_object - a hashref or object to provide initial valuesExamples of creating a form object with new:
my $form = MyApp::Form::User->new;
# database form using a row object
my $form = MyApp::Form::Member->new( item => $row );
# a dynamic form (no form class has been defined)
my $form = HTML::FormHandler::Model::DBIC->new(
item_id => $id,
item_class => 'User',
schema => $schema,
field_list => [
name => 'Text',
active => 'Boolean',
],
);See the model class for more information about the 'item', 'item_id', 'item_class', and schema (for the DBIC model). HTML::FormHandler::Model::DBIC.
FormHandler forms are handled in two steps: 1) create with 'new', 2) handle with 'process'. FormHandler doesn't care whether most parameters are set on new or process or update, but a 'field_list' argument must be passed in on 'new' since the fields are built at construction time.
Processing the form
process
Call the 'process' method on your form to perform validation and update. A database form must have either an item (row object) or a schema, item_id (row primary key), and item_class (usually set in the form). A non-database form requires only parameters.
$form->process( item => $book, params => $c->req->parameters );
$form->process( item_id => $item_id,
schema => $schema, params => $c->req->parameters );
$form->process( params => $c->req->parameters );This process method returns the 'validated' flag. ($form->validated) If it is a database form and the form validates, the database row will be updated.
After the form has been processed, you can get a parameter hashref suitable for using to fill in the form from $form->fif. A hash of inflated values (that would be used to update the database for a database form) can be retrieved with $form->value.
params
Parameters are passed in or already set when you call 'process'. HFH gets data to validate and store in the database from the params hash. If the params hash is empty, no validation is done, so it is not necessary to check for POST before calling $form->process.
Params can either be in the form of CGI/HTTP style params:
{
user_name => "Joe Smith",
occupation => "Programmer",
'addresses.0.street' => "999 Main Street",
'addresses.0.city' => "Podunk",
'addresses.0.country' => "UT",
'addresses.0.address_id' => "1",
'addresses.1.street' => "333 Valencia Street",
'addresses.1.city' => "San Franciso",
'addresses.1.country' => "UT",
'addresses.1.address_id' => "2",
}or as structured data in the form of hashes and lists:
{
addresses => [
{
city => 'Middle City',
country => 'GK',
address_id => 1,
street => '101 Main St',
},
{
city => 'DownTown',
country => 'UT',
address_id => 2,
street => '99 Elm St',
},
],
'occupation' => 'management',
'user_name' => 'jdoe',
}CGI style parameters will be converted to hashes and lists for HFH to operate on.
You can add an additional param when setting params:
$form->process( params => { %{$c->req->params}, new_param => 'something' } );Getting data out
fif (fill in form)
Returns a hash of values suitable for use with HTML::FillInForm or for filling in a form with $form->fif->{fieldname}. The fif value for a 'title' field in a TT form:
[% form.fif.title %]Or you can use the 'fif' method on individual fields:
[% form.field('title').fif %]value
Returns a hashref of all field values. Useful for non-database forms, or if you want to update the database yourself. The 'fif' method returns a hashref with the field names for the keys and the field's 'fif' for the values; 'value' returns a hashref with the field accessors for the keys, and the field's 'value' (possibly inflated) for the the values.
Forms containing arrays to be processed with HTML::FormHandler::Field::Repeatable will have parameters with dots and numbers, like 'addresses.0.city', while the values hash will transform the fields with numbers to arrays.
Accessing and setting up fields
Fields are declared with a number of attributes which are defined in HTML::FormHandler::Field. If you want additional attributes you can define your own field classes (or apply a role to a field class - see HTML::FormHandler::Manual::Cookbook). The field 'type' (used in field definitions) is the short class name of the field class.
has_field
The most common way of declaring fields is the 'has_field' syntax. Using the 'has_field' syntax sugar requires use HTML::FormHandler::Moose; or use HTML::FormHandler::Moose::Role; in a role. See HTML::FormHandler::Manual::Intro
use HTML::FormHandler::Moose;
has_field 'field_name' => ( type => 'FieldClass', .... );field_list
A 'field_list' is an array of field definitions which can be used as an alternative to 'has_field' in small, dynamic forms.
field_list => [
field_one => {
type => 'Text',
required => 1
},
field_two => 'Text,
]Or the field list can be set inside a form class, when you want to add fields to the form depending on some other state.
sub field_list {
my $self = shift;
my $fields = $self->schema->resultset('SomeTable')->
search({user_id => $self->user_id, .... });
my @field_list;
while ( my $field = $fields->next )
{
< create field list >
}
return \@field_list;
}field_name_space
Use to set the name space used to locate fields that start with a "+", as: "+MetaText". Fields without a "+" are loaded from the "HTML::FormHandler::Field" name space. If 'field_name_space' is not set, then field types with a "+" must be the complete package name.
fields
The array of fields, objects of HTML::FormHandler::Field or its subclasses. A compound field will itself have an array of fields, so this is a tree structure.
field($name)
This is the method that is usually called to access a field:
my $title = $form->field('title')->value;
[% f = form.field('title') %]
my $city = $form->field('addresses.0.city')->value;Pass a second true value to die on errors.
Constraints and validation
Most validation is performed on a per-field basis, and there are a number of different places in which validation can be performed.
Apply actions
The 'actions' array contains a sequence of transformations, constraints (including Moose type constraints) which will be applied in order. The current value of the field is passed in to the subroutines, but it has no access to other field information. This is probably the best place to put constraints and transforms if all that is needed is the current value. The HTML::FormHandler::Field::Compound fields receive as value a hash containing values of their child fields - this may be used for easy creation of objects (like DateTime). See "apply" in HTML::FormHandler::Field for more documentation.
has_field 'test' => ( apply => [ 'MyConstraint',
{ check => sub {... },
message => '....' },
{ transform => sub { ... },
message => '....' }
] );Field class validate method
The 'validate' method can be used in custom field classes to perform additional validation. It has access to the field ($self). This method is called after the actions are performed.
Form class validation for individual fields
You can define a method in your form class to perform validation on a field. This method is the equivalent of the field class validate method except it is in the form class, so you might use this validation method if you don't want to create a field subclass.
It has access to the form ($self) and the field. This method is called after the field class 'validate' method, and is not called if the value for the field is empty ('', undef). (If you want an error message when the field is empty, use the 'required' flag and message.) The name of this method can be set with 'set_validate' on the field. The default is 'validate_' plus the field name:
sub validate_testfield { my ( $self, $field ) = @_; ... }If the field name has dots they should be replaced with underscores.
validate
(This method used to be called 'cross_validate'. It was renamed to 'validate' to make the api more consistent.) This is a form method that is useful for cross checking values after they have been saved as their final validated value, and for performing more complex dependency validation. It is called after all other field validation is done, and whether or not validation has succeeded, so it has access to the post-validation values of all the fields.
This is the best place to do validation checks that depend on the values of more than one field.
Accessing errors
has_errors - returns true or false
error_fields - returns list of fields with errors
errors - returns array of error messages for the entire form
num_errors - number of errors in formEach field has an array of error messages. (errors, has_errors, num_errors, clear_errors)
$form->field('title')->errors;Compound fields also have an error of error_fields.
Clear form state
The clear method is called at the beginning of 'process' if the form object is reused, such as when it is persistent in a Moose attribute, or in tests. If you add other attributes to your form that are set on each request, you may need to clear those yourself.
If you do not call the form's 'process' method on a persistent form, such as in a REST controller's non-POST method or if you only call process when the form is posted, you will also need to call $form->clear.
Miscellaneous attributes
name
The form's name. Useful for multiple forms. It is used to construct the default 'id' for fields, and is used for the HTML field name when 'html_prefix' is set. The default is "form" + a one to three digit random number.
init_object
If an 'init_object' is supplied on form creation, it will be used instead of the 'item' to pre-populate the values in the form. This can be useful when populating a form from default values stored in a similar but different object than the one the form is creating. The 'init_object' should be either a hash or the same type of object that the model uses (a DBIx::Class row for the DBIC model).
ctx
Place to store application context for your use in your form's methods.
language_handle, build_language_handle
Holds a Locale::Maketext language handle
The builder for this attribute gets the Locale::Maketext language handle from the environment variable $ENV{LANGUAGE_HANDLE}, or creates a default language handler using HTML::FormHandler::I18N. The language handle is used in the field's add_error method to allow localizing.
dependency
Arrayref of arrayrefs of fields. If one of a group of fields has a value, then all of the group are set to 'required'.
has '+dependency' => ( default => sub { [
['street', 'city', 'state', 'zip' ],] }
);Flags
validated
Flag that indicates if form has been validated. You might want to use this flag if you're doing something in between process and returning, such as setting a stash key.
$form->process( ... );
$c->stash->{...} = ...;
return unless $form->validated;ran_validation
Flag to indicate that validation has been run. This flag will be false when the form is initially loaded and displayed, since validation is not run until FormHandler has params to validate.
verbose
Flag to dump diagnostic information. See 'dump_fields' and 'dump_validated'.
html_prefix
Flag to indicate that the form name is used as a prefix for fields in an HTML form. Useful for multiple forms on the same HTML page. The prefix is stripped off of the fields before creating the internal field name, and added back in when returning a parameter hash from the 'fif' method. For example, the field name in the HTML form could be "book.borrower", and the field name in the FormHandler form (and the database column) would be just "borrower".
has '+name' => ( default => 'book' );
has '+html_prefix' => ( default => 1 );Also see the Field attribute "html_name", a convenience function which will return the form name + "." + field full_name
For use in HTML
http_method - For storing 'post' or 'get'
action - Store the form 'action' on submission. No default value.
enctype - Request enctype
uuid - generates a string containing an HTML field with UUIDSUPPORT
IRC:
Join #formhandler on irc.perl.orgMailing list:
http://groups.google.com/group/formhandlerCode repository:
http://github.com/gshank/html-formhandler/tree/masterSEE ALSO
HTML::FormHandler::Manual::Tutorial
HTML::FormHandler::Manual::Intro
HTML::FormHandler::Manual::Templates
HTML::FormHandler::Manual::Cookbook
HTML::FormHandler::Model::DBIC
HTML::FormHandler::Render::Simple
CONTRIBUTORS
gshank: Gerda Shank <gshank@cpan.org> zby: Zbigniew Lukasiak <zby@cpan.org> t0m: Tomas Doran <bobtfish@bobtfish.net>
Initially based on the source code of Form::Processor by Bill Moseley
COPYRIGHT
This library is free software, you can redistribute it and/or modify it under the same terms as Perl itself.