oracular (3) HTML::FormHandler.3pm.gz
NAME
HTML::FormHandler - HTML forms using Moose
VERSION
version 0.40068
SYNOPSIS
See the manual at HTML::FormHandler::Manual.
use HTML::FormHandler; # or a custom form: use MyApp::Form::User;
my $form = HTML::FormHandler->new( .... );
$form->process( params => $params );
my $rendered_form = $form->render;
if( $form->validated ) {
# perform validated form actions
}
else {
# perform non-validated actions
}
Or, if you want to use a form 'result' (which contains only the form values and error messages) instead:
use MyApp::Form; # or a generic form: use HTML::FormHandler;
my $form = MyApp::Form->new( .... );
my $result = $form->run( params => $params );
if( $result->validated ) {
# perform validated form actions
}
else {
# perform non-validated actions
$result->render;
}
An example of a custom form class:
package MyApp::Form::User;
use HTML::FormHandler::Moose;
extends 'HTML::FormHandler';
use Moose::Util::TypeConstraints;
has '+item_class' => ( default => 'User' );
has_field 'name' => ( type => 'Text' );
has_field 'age' => ( type => 'PosInteger', apply => [ 'MinimumAge' ] );
has_field 'birthdate' => ( type => 'DateTime' );
has_field 'birthdate.month' => ( type => 'Month' );
has_field 'birthdate.day' => ( type => 'MonthDay' );
has_field 'birthdate.year' => ( type => 'Year' );
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;
A dynamic form - one that does not use a custom form class - may be created using the 'field_list'
attribute to set fields:
my $form = HTML::FormHandler->new(
name => 'user_form',
item => $user,
field_list => [
'username' => {
type => 'Text',
apply => [ { check => qr/^[0-9a-z]*\z/,
message => 'Contains invalid characters' } ],
},
'select_bar' => {
type => 'Select',
options => \@select_options,
multiple => 1,
size => 4,
},
],
);
FormHandler does not provide a custom controller for Catalyst because it isn't necessary. Interfacing to
FormHandler is only a couple of lines of code. See HTML::FormHandler::Manual::Catalyst for more details,
or Catalyst::Manual::Tutorial::09_AdvancedCRUD::09_FormHandler.
DESCRIPTION
*** Although documentation in this file provides some overview, it is mainly intended for API
documentation. See HTML::FormHandler::Manual::Intro for an introduction, with links to other
documentation.
HTML::FormHandler maintains a clean separation between form construction and form rendering. It allows
you to define your forms and fields in a number of flexible ways. Although it provides renderers for
HTML, you can define custom renderers for any kind of presentation.
HTML::FormHandler allows you to define 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 be used to process
structured data that doesn't come from an HTML form.
One of its goals is to keep the controller/application program 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 shouldn't have to 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 define custom renderers and display your
rendered forms however you want.
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, and use Moose method modifiers.
FormHandler forms are Perl classes, so there's a lot of flexibility in what you can do.
HTML::FormHandler provides rendering through roles which are applied to form and field classes (although
there's no reason you couldn't write a renderer as an external object either). There are currently two
flavors: all-in-one solutions like HTML::FormHandler::Render::Simple and HTML::FormHandler::Render::Table
that contain methods for rendering field widget classes, and the HTML::FormHandler::Widget roles, which
are more atomic roles which are automatically applied to fields and form. See
HTML::FormHandler::Manual::Rendering for more details. (And you can easily use hand-built forms -
FormHandler doesn't care.)
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,
);
No attributes are required on new. The form's fields will be built from the form definitions. If no
initial data object or defaults have 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 schema
The following are sometimes passed in, but are also often set in the form class:
item_class - source name of row
dependency - (see dependency)
field_list - an array of field definitions
init_object - a hashref or object to provide initial values
Examples 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',
submit_btn => 'Submit',
],
);
See the model class for more information about '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.
If you want to update field attributes on the 'process' call, you can use an 'update_field_list' or
'defaults' hashref attribute , or subclass update_fields in your form. The 'update_field_list' hashref
can be used to set any field attribute. The 'defaults' hashref will update only the 'default' attribute
in the field. (There are a lot of ways to set defaults. See HTML::FormHandler::Manual::Defaults.)
$form->process( defaults => { foo => 'foo_def', bar => 'bar_def' } );
$form->process( update_field_list => { foo => { label => 'New Label' } });
Field results are built on the 'new' call, but will then be re-built on the process call. If you always
use 'process' before rendering the form, accessing fields, etc, you can set the 'no_preload' flag to skip
this step.
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".
If you don't want to update the database on this process call, you can set the 'no_update' flag:
$form->process( item => $book, params => $params, no_update => 1 );
params
Parameters are passed in when you call 'process'. HFH gets data to validate and store in the database
from the params hash. If the params hash is empty, no validation is done, so it is not necessary to
check for POST before calling "$form->process". (Although see the 'posted' option for complications.)
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 Francisco",
'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.
posted
Note that FormHandler by default uses empty params as a signal that the form has not actually been
posted, and so will not attempt to validate a form with empty params. Most of the time this works OK, but
if you have a small form with only the controls that do not return a post parameter if unselected
(checkboxes and select lists), then the form will not be validated if everything is unselected. For this
case you can either add a hidden field as an 'indicator', or use the 'posted' flag:
$form->process( posted => ($c->req->method eq 'POST'), params => ... );
The 'posted' flag also works to prevent validation from being performed if there are extra params in the
params hash and it is not a 'POST' request.
Getting data out
fif (fill in form)
If you don't use FormHandler rendering and want to fill your form values in using some other method (such
as with HTML::FillInForm or using a template) this returns a hash of values that are equivalent to params
which you may use to fill in your form.
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 %]
If you use FormHandler to render your forms or field you probably won't use these methods.
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 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, used when searching the 'field_name_space' for 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 to create fields.
field_list => [
field_one => {
type => 'Text',
required => 1
},
field_two => 'Text,
]
The field_list array takes elements which are either a field_name key pointing to a 'type' string or a
field_name key pointing to a hashref of field attributes. You can also provide an array of hashref
elements with the name as an additional attribute. The field list can be set inside a form class, when
you want to add fields to the form depending on some other state, although you can also create all the
fields and set some of them inactive.
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;
}
update_field_list
Used to dynamically set particular field attributes on the 'process' (or 'run') call. (Will not create
fields.)
$form->process( update_field_list => {
foo_date => { format => '%m/%e/%Y', date_start => '10-01-01' } },
params => $params );
The 'update_field_list' is processed by the 'update_fields' form method, which can also be used in a form
to do specific field updates:
sub update_fields {
my $self = shift;
$self->field('foo')->temp( 'foo_temp' );
$self->field('bar')->default( 'foo_value' );
$self->next::method();
}
(Note that you although you can set a field's 'default', you can't set a field's 'value' directly here,
since it will be overwritten by the validation process. Set the value in a field validation method.)
update_subfields
Yet another way to provide settings for the field, except this one is intended for use in roles and
compound fields, and is only executed when the form is initially built. It takes the same field name keys
as 'update_field_list', plus 'all', 'by_flag', and 'by_type'.
sub build_update_subfields {{
all => { tags => { wrapper_tag => 'p' } },
foo => { element_class => 'blue' },
}}
The 'all' hash key will apply updates to all fields. (Conflicting attributes in a field definition take
precedence.)
The 'by_flag' hash key will apply updates to fields with a particular flag. The currently supported
subkeys are 'compound', 'contains', and 'repeatable'. (For repeatable instances, in addition to
'contains' you can also use the 'repeatable' key and the 'init_contains' attribute.) This is useful for
turning on the rendering wrappers for compounds and repeatables, which are off by default. (The
repeatable instances are wrapped by default.)
sub build_update_subfields {{
by_flag => { compound => { do_wrapper => 1 } },
by_type => { Select => { element_class => ['sel_elem'] } },
}}
The 'by_type' hash key will provide values to all fields of a particular type.
defaults
This is a more specialized version of the 'update_field_list'. It can be used to provide 'default'
settings for fields, in a shorthand way (you don't have to say 'default' for every field).
$form->process( defaults => { foo => 'this_foo', bar => 'this_bar' }, ... );
active/inactive
A field can be marked 'inactive' and set to active at new or process time by specifying the field name in
the 'active' array:
has_field 'foo' => ( type => 'Text', inactive => 1 );
...
my $form = MyApp::Form->new( active => ['foo'] );
...
$form->process( active => ['foo'] );
Or a field can be a normal active field and set to inactive at new or process time:
has_field 'bar';
...
my $form = MyApp::Form->new( inactive => ['foo'] );
...
$form->process( inactive => ['foo'] );
Fields specified as active/inactive on new will have the form's inactive/active arrayref cleared and the
field's inactive flag set appropriately, so that the state will be effective for the life of the form
object. Fields specified as active/inactive on 'process' will have the field's '_active' flag set for the
life of the request (the _active flag will be cleared when the form is cleared).
The 'sorted_fields' method returns only active fields, sorted according to the 'order' attribute. The
'fields' method returns all fields.
foreach my $field ( $self->sorted_fields ) { ... }
You can test whether a field is active by using the field 'is_active' and 'is_inactive' methods.
field_name_space
Use to look for field during form construction. If a field is not found with the field_name_space (or
HTML::FormHandler/HTML::FormHandlerX), the 'type' must start with a '+' and be the complete package name.
fields
The array of fields, objects of HTML::FormHandler::Field or its subclasses. A compound field will itself
have an array of fields, so this is a tree structure.
sorted_fields
Returns those fields from the fields array which are currently active. This is the method that returns
the fields that are looped through when rendering.
field($name), subfield($name)
'field' 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.
Since fields are searched for using the form as a base, if you want to find a sub field in a compound
field method, the 'subfield' method may be more useful, since you can search starting at the current
field. The 'chained' method also works:
-- in a compound field --
$self->field('media.caption'); # fails
$self->field('media')->field('caption'); # works
$self->subfield('media.caption'); # works
Constraints and validation
Most validation is performed on a per-field basis, and there are a number of different places in which
validation can be performed.
See also HTML::FormHandler::Manual::Validation.
Form class validation for individual fields
You can define a method in your form class to perform validation on a field. This method is the
equivalent of the field class validate method except it is in the form class, so you might use this
validation method if you don't want to create a field subclass.
It has access to the form ($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 or the form 'validate' method.) 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, $field ) = @_; ... }
If the field name has dots they should be replaced with underscores.
Note that you can also provide a coderef which will be a method on the field:
has_field 'foo' => ( validate_method => \&validate_foo );
validate
This is a form method that is useful for cross checking values after they have been saved as their final
validated value, and for performing more complex dependency validation. It is called after all other
field validation is done, and whether or not validation has succeeded, so it has access to the post-
validation values of all the fields.
This is the best place to do validation checks that depend on the values of more than one field.
Accessing errors
Also see HTML::FormHandler::Manual::Errors.
Set an error in a field with "$field->add_error('some error string');". Set a form error not tied to a
specific field with "$self->add_form_error('another error string');". The 'add_error' and
'add_form_error' methods call localization. If you want to skip localization for a particular error, you
can use 'push_errors' or 'push_form_errors' instead.
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 form
Each field has an array of error messages. (errors, has_errors, num_errors, clear_errors)
$form->field('title')->errors;
Compound fields also have an array of error_fields.
Clear form state
The clear method is called at the beginning of 'process' if the form object is reused, such as when it is
persistent in a Moose attribute, or in tests. If you add other attributes to your form that are set on
each request, you may need to clear those yourself.
If you do not call the form's 'process' method on a persistent form, such as in a REST controller's non-
POST method, or if you only call process when the form is posted, you will also need to call
"$form->clear".
The 'run' method which returns a result object always performs 'clear', to keep the form object clean.
Miscellaneous attributes
name
The form's name. Useful for multiple forms. Used for the form element 'id'. When 'html_prefix' is set
it is used to construct the field 'id' and 'name'. The default is "form" + a one to three digit random
number. Because the HTML standards have flip-flopped on whether the HTML form element can contain a
'name' attribute, please set a name attribute using 'form_element_attr'.
init_object
An 'init_object' may 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). It can be set in a variety of ways:
my $form = MyApp::Form->new( init_object => { .... } );
$form->process( init_object => {...}, ... );
has '+init_object' => ( default => sub { { .... } } );
sub init_object { my $self = shift; .... }
The method version is useful if the organization of data in your form does not map to an existing or
database object in an automatic way, and you need to create a different type of object for
initialization. (You might also want to do 'update_model' yourself.)
Also see the 'use_init_obj_over_item' and the 'use_init_obj_when_no_accessor_in_item' flags, if you want
to provide both an item and an init_object, and use the values from the init_object.
The 'use_init_obj_when_no_accessor_in_item' flag is particularly useful when some of the fields in your
form come from the database and some are process or environment type flags that are not in the database.
You can provide defaults from both a database row and an 'init_object.
ctx
Place to store application context for your use in your form's methods.
language_handle
See 'language_handle' and '_build_language_handle' in HTML::FormHandler::TraitFor::I18N.
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, is_valid
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. ('is_valid' is a synonym for this flag)
$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, dump, peek
Flag to dump diagnostic information. See 'dump_fields' and 'dump_validated'. 'Peek' can be useful in
diagnosing bugs. It will dump a brief listing of the fields and results.
$form->process( ... );
$form->peek;
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
is_html5
Flag to indicate the fields will render using specialized attributes for html5. Set to 0 by default.
use_defaults_over_obj
The 'normal' precedence is that if there is an accessor in the item/init_object that value is used and
not the 'default'. This flag makes the defaults of higher precedence. Mainly useful if providing an empty
row on create.
use_init_obj_over_item
If you are providing both an item and an init_object, and want the init_object to be used for defaults
instead of the item.
For use in HTML
form_element_attr - hashref for setting arbitrary HTML attributes
set in form with: sub build_form_element_attr {...}
form_element_class - arrayref for setting form tag class
form_wrapper_attr - hashref for form wrapper element attributes
set in form with: sub build_form_wrapper_attr {...}
form_wrapper_class - arrayref for setting wrapper class
do_form_wrapper - flag to wrap the form
http_method - For storing 'post' or 'get'
action - Store the form 'action' on submission. No default value.
uuid - generates a string containing an HTML field with UUID
form_tags - hashref of tags for use in rendering code
widget_tags - rendering tags to be transferred to fields
Discouraged (use form_element_attr instead):
style - adds a 'style' attribute to the form tag
enctype - Request enctype
Note that the form tag contains an 'id' attribute which is set to the form name. The standards have been
flip-flopping over whether a 'name' attribute is valid. It can be set with 'form_element_attr'.
The rendering of the HTML attributes is done using the 'process_attrs' function and the
'element_attributes' or 'wrapper_attributes' method, which adds other attributes in for backward
compatibility, and calls the 'html_attributes' hook.
For HTML attributes, there is a form method hook, 'html_attributes', which can be used to
customize/modify/localize form & field HTML attributes. Types: element, wrapper, label, form_element,
form_wrapper, checkbox_label
sub html_attributes {
my ( $self, $obj, $type, $attrs, $result ) = @_;
# obj is either form or field
$attr->{class} = 'label' if $type eq 'label';
$attr->{placeholder} = $self->_localize($attr->{placeholder})
if exists $attr->{placeholder};
return $attr;
}
Also see the documentation in HTML::FormHandler::Field and in HTML::FormHandler::Manual::Rendering.
SUPPORT
IRC:
Join #formhandler on irc.perl.org
Mailing list:
http://groups.google.com/group/formhandler
Code repository:
http://github.com/gshank/html-formhandler/tree/master
Bug tracker:
https://rt.cpan.org/Dist/Display.html?Name=HTML-FormHandler
SEE ALSO
HTML::FormHandler::Manual
HTML::FormHandler::Manual::Tutorial
HTML::FormHandler::Manual::Intro
HTML::FormHandler::Manual::Templates
HTML::FormHandler::Manual::Cookbook
HTML::FormHandler::Manual::Rendering
HTML::FormHandler::Manual::Reference
HTML::FormHandler::Field
HTML::FormHandler::Model::DBIC
HTML::FormHandler::Render::Simple
HTML::FormHandler::Render::Table
HTML::FormHandler::Moose
CONTRIBUTORS
gshank: Gerda Shank <gshank@cpan.org> zby: Zbigniew Lukasiak <zby@cpan.org> t0m: Tomas Doran <bobtfish@bobtfish.net> augensalat: Bernhard Graf <augensalat@gmail.com> cubuanic: Oleg Kostyuk <cub.uanic@gmail.com> rafl: Florian Ragwitz <rafl@debian.org> mazpe: Lester Ariel Mesa dew: Dan Thomas koki: Klaus Ita jnapiorkowski: John Napiorkowski lestrrat: Daisuke Maki hobbs: Andrew Rodland Andy Clayton boghead: Bryan Beeley Csaba Hetenyi Eisuke Oishi Lian Wan Situ Murray Nick Logan Vladimir Timofeev diegok: Diego Kuperman ijw: Ian Wells amiri: Amiri Barksdale ozum: Ozum Eldogan lukast: Lukas Thiemeier Initially based on the source code of Form::Processor by Bill Moseley
AUTHOR
FormHandler Contributors - see HTML::FormHandler
COPYRIGHT AND LICENSE
This software is copyright (c) 2017 by Gerda Shank.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
programming language system itself.