Provided by: libhtml-formhandler-perl_0.40068-1_all bug

NAME

       HTML::FormHandler::Field - base class for fields

VERSION

       version 0.40068

SYNOPSIS

       Instances of Field subclasses are generally built by HTML::FormHandler from 'has_field'
       declarations or the field_list, but they can also be constructed using new for test
       purposes (since there's no standard way to add a field to a form after construction).

           use HTML::FormHandler::Field::Text;
           my $field = HTML::FormHandler::Field::Text->new( name => $name, ... );

       In your custom field class:

           package MyApp::Field::MyText;
           use HTML::FormHandler::Moose;
           extends 'HTML::FormHandler::Field::Text';

           has 'my_attribute' => ( isa => 'Str', is => 'rw' );

           apply [ { transform => sub { ... } },
                   { check => ['fighter', 'bard', 'mage' ], message => '....' }
                 ];
           1;

DESCRIPTION

       This is the base class for form fields. The 'type' of a field class is used in the
       FormHandler field_list or has_field to identify which field class to load from the
       'field_name_space' (or directly, when prefixed with '+').  If the type is not specified,
       it defaults to Text.

       See HTML::FormHandler::Manual::Fields for a list of the fields and brief descriptions of
       their structure.

ATTRIBUTES

   Names, types, accessor
       name
           The name of the field. Used in the HTML form. Often a db accessor.  The only required
           attribute.

       type
           The class or type of the field. The 'type' of HTML::FormHandler::Field::Money is
           'Money'. Classes that you define yourself are prefixed with '+'.

       accessor
           If the name of your field is different than your database accessor, use this attribute
           to provide the accessor.

       full_name
           The name of the field with all parents:

              'event.start_date.month'

       full_accessor
           The field accessor with all parents.

       html_name
           The full_name plus the form name if 'html_prefix' is set.

       input_param
           By default we expect an input parameter based on the field name.  This allows you to
           look for a different input parameter.

   Field data
       inactive, is_inactive, is_active
           Set the 'inactive' attribute to 1 if this field is inactive. The 'inactive' attribute
           that isn't set or is set to 0 will make a field 'active'.  This provides a way to
           define fields in the form and selectively set them to inactive.  There is also an
           '_active' attribute, for internal use to indicate that the field has been
           activated/inactivated on 'process' by the form's 'active'/'inactive' attributes.

           You can use the is_inactive and is_active methods to check whether this particular
           field is active.

              if( $form->field('foo')->is_active ) { ... }

       input
           The input string from the parameters passed in.

       value
           The value as it would come from or go into the database, after being acted on by
           inflations/deflations and transforms. Used to construct the "$form->values" hash.
           Validation and constraints act on 'value'.

           See also HTML::FormHandler::Manual::InflationDeflation.

       fif Values used to fill in the form. Read only. Use a deflation to get from 'value' to
           'fif' if an inflator was used. Use 'fif_from_value' attribute if you want to use the
           field 'value' to fill in the form.

              [% form.field('title').fif %]

       init_value
           Initial value populated by init_from_object. You can tell if a field has changed by
           comparing 'init_value' and 'value'. Read only.

       input_without_param
           Input for this field if there is no param. Set by default for Checkbox, and Select,
           since an unchecked checkbox or unselected pulldown does not return a parameter.

   Form, parent
       form
           A reference to the containing form.

       parent
           A reference to the parent of this field. Compound fields are the parents for the
           fields they contain.

   Errors
       errors
           Returns the error list for the field. Also provides 'num_errors', 'has_errors',
           'push_errors' and 'clear_errors' from Array trait. Use 'add_error' to add an error to
           the array if you want to use a MakeText language handle. Default is an empty list.

       add_error
           Add an error to the list of errors. Error message will be localized using '_localize'
           method.  See also HTML::FormHandler::TraitFor::I18N.

               return $field->add_error( 'bad data' ) if $bad;

       error_fields
           Compound fields will have an array of errors from the subfields.

       localize_meth
           Set the method used to localize.

   Attributes for creating HTML
       The 'element_attr' hashref attribute can be used to set arbitrary HTML attributes on a
       field's input tag.

          has_field 'foo' => ( element_attr => { readonly => 1, my_attr => 'abc' } );

       Note that the 'id' and 'type' attributes are not set using element_attr. Use the field's
       'id' attribute (or 'build_id_method') to set the id.

       The 'label_attr' hashref is for label attributes, and the 'wrapper_attr' is for attributes
       on the wrapping element (a 'div' for the standard 'simple' wrapper).

       A 'javascript' key in one of the '_attr' hashes will be inserted into the element as-is.

       The following are used in rendering HTML, but are handled specially.

          label       - Text label for this field. Defaults to ucfirst field name.
          build_label_method - coderef for constructing the label
          wrap_label_method - coderef for constructing a wrapped label
          id          - Useful for javascript (default is html_name. to prefix with
                        form name, use 'html_prefix' in your form)
          build_id_method - coderef for constructing the id
          render_filter - Coderef for filtering fields before rendering. By default
                        changes >, <, &, " to the html entities
          disabled    - Boolean to set field disabled

       The order attribute may be used to set the order in which fields are rendered.

          order       - Used for sorting errors and fields. Built automatically,
                        but may also be explicitly set

       The following are discouraged. Use 'element_attr', 'label_attr', and 'wrapper_attr'
       instead.

          title       - instead use element_attr => { title => '...' }
          style       - instead use element_attr => { style => '...' }
          tabindex    - instead use element_attr => { tabindex => 1 }
          readonly    - instead use element_attr => { readonly => 'readonly' }

       Rendering of the various HTML attributes is done by calling the 'process_attrs' function
       (from HTML::FormHandler::Render::Util) and passing in a method that adds in error classes,
       provides backward compatibility with the deprecated attributes, etc.

           attribute hashref  class attribute        wrapping method
           =================  =================      ================
           element_attr       element_class          element_attributes
           label_attr         label_class            label_attributes
           wrapper_attr       wrapper_class          wrapper_attributes
                              element_wrapper_class  element_wrapper_attributes

       ('element_wrapper' is for an inner div around the input element, not including the label.
       Used for Bootstrap3 rendering, but also available in the Simple wrapper.)  The slots for
       the class attributes are arrayrefs; they will coerce a string into an arrayref.  In
       addition, these 'wrapping methods' call a hook method in the form class,
       'html_attributes', which you can use to customize and localize the various attributes.
       (Field types: 'element', 'wrapper', 'label')

          sub html_attributes {
              my ( $self, $field, $type, $attr ) = @_;
              $attr->{class} = 'label' if $type eq 'label';
              return $attr;
          }

       The 'process_attrs' function will also handle an array of strings, such as for the 'class'
       attribute.

   tags
       A hashref containing flags and strings for use in the rendering code.  The value of a tag
       can be a string, a coderef (accessed as a method on the field) or a block specified with a
       percent followed by the blockname ('%blockname').

       Retrieve a tag with 'get_tag'. It returns a '' if the tag doesn't exist.

       This attribute used to be named 'widget_tags', which is deprecated.

   html5_type_attr [string]
       This string is used when rendering an input element as the value for the type attribute.
       It is used when the form has the is_html5 flag on.

   widget
       The 'widget' attribute is used in rendering, so if you are not using FormHandler's
       rendering facility, you don't need this attribute.  It is used in generating HTML, in
       templates and the rendering roles. Fields of different type can use the same widget.

       This attribute is set in the field classes, or in the fields defined in the form. If you
       want a new widget type, create a widget role, such as
       MyApp::Form::Widget::Field::MyWidget. Provide the name space in the 'widget_name_space'
       attribute, and set the 'widget' of your field to the package name after the
       Field/Form/Wrapper:

          has_field 'my_field' => ( widget => 'MyWidget' );

       If you are using a template based rendering system you will want to create a widget
       template.  (see HTML::FormHandler::Manual::Templates)

       Widget types for some of the provided field classes:

           Widget                 : Field classes
           -----------------------:---------------------------------
           Text                   : Text, Integer
           Checkbox               : Checkbox, Boolean
           RadioGroup             : Select, Multiple, IntRange (etc)
           Select                 : Select, Multiple, IntRange (etc)
           CheckboxGroup          : Multiple select
           TextArea               : TextArea
           Compound               : Compound, Repeatable, DateTime
           Password               : Password
           Hidden                 : Hidden
           Submit                 : Submit
           Reset                  : Reset
           NoRender               :
           Upload                 : Upload

       Widget roles are automatically applied to field classes unless they already have a
       'render' method, and if the 'no_widgets' flag in the form is not set.

       You can create your own widget roles and specify the namespace in 'widget_name_space'. In
       the form:

           has '+widget_name_space' => ( default => sub { ['MyApp::Widget'] } );

       If you want to use a fully specified role name for a widget, you can prefix it with a '+':

          widget => '+MyApp::Widget::SomeWidget'

       For more about widgets, see HTML::FormHandler::Manual::Rendering.

   Flags
          password  - prevents the entered value from being displayed in the form
          writeonly - The initial value is not taken from the database
          noupdate  - Do not update this field in the database (does not appear in $form->value)

   Defaults
       See also the documentation on "Defaults" in HTML::FormHandler::Manual::Intro.

       default_method, set_default
           Supply a coderef (which will be a method on the field) with 'default_method' or the
           name of a form method with 'set_default' (which will be a method on the form). If not
           specified and a form method with a name of "default_<field_name>" exists, it will be
           used.

       default
           Provide an initial value just like the 'set_default' method, except in the field
           declaration:

             has_field 'bax' => ( default => 'Default bax' );

           FormHandler has flipped back and forth a couple of times about whether a default
           specified in the has_field definition should override values provided in an initial
           item or init_object. Sometimes people want one behavior, and sometimes the other. Now
           'default' does *not* override.

           If you pass in a model object with "item => $row" or an initial object with
           "init_object => {....}" the values in that object will be used instead of values
           provided in the field definition with 'default' or 'default_fieldname'.  If you want
           defaults that override or supplement the item/init_object, you can use the form flags
           'use_defaults_over_obj', 'use_init_obj_over_item', and
           'use_init_obj_when_no_accessor_in_item'.

           You could also put your defaults into your row or init_object instead.

       default_over_obj
           This is deprecated; look into using 'use_defaults_over_obj' or
           'use_init_obj_over_item' flags instead. They allow using the standard 'default'
           attribute.

           Allows setting defaults which will override values provided with an item/init_object.
           (And only those. Will not be used for defaults without an item/init_object.)

              has_field 'quux' => ( default_over_obj => 'default quux' );

           At this time there is no equivalent of 'set_default', but the type of the attribute is
           not defined so you can provide default values in a variety of other ways, including
           providing a trait which does 'build_default_over_obj'. For examples, see tests in the
           distribution.

Constraints and Validations

       See also HTML::FormHandler::Manual::Validation.

   Constraints set in attributes
       required
           Flag indicating whether this field must have a value

       unique
           For DB field - check for uniqueness. Action is performed by the DB model.

       messages
               messages => { required => '...', unique => '...' }

           Set messages created by FormHandler by setting in the 'messages' hashref. Some field
           subclasses have additional settable messages.

           required:  Error message text added to errors if required field is not present.  The
           default is "Field <field label> is required".

       range_start
       range_end
           Field values are validated against the specified range if one or both of range_start
           and range_end are set and the field does not have 'options'.

           The IntRange field uses this range to create a select list with a range of integers.

           In a FormHandler field_list:

               age => {
                   type            => 'Integer',
                   range_start     => 18,
                   range_end       => 120,
               }

       not_nullable
           Fields that contain 'empty' values such as '' are changed to undef in the validation
           process.  If this flag is set, the value is not changed to undef. If your database
           column requires an empty string instead of a null value (such as a NOT NULL column),
           set this attribute.

               has_field 'description' => (
                   type => 'TextArea',
                   not_nullable => 1,
               );

           This attribute is also used when you want an empty array to stay an empty array and
           not be set to undef.

           It's also used when you have a compound field and you want the 'value' returned to
           contain subfields with undef, instead of the whole field to be undef.

   apply
       Use the 'apply' keyword to specify an ArrayRef of constraints and coercions to be executed
       on the field at validate_field time.

          has_field 'test' => (
             apply => [ 'MooseType',
                        { check => sub {...}, message => { } },
                        { transform => sub { ... lc(shift) ... } }
                      ],
          );

       See more documentation in HTML::FormHandler::Manual::Validation.

   trim
       An action to trim the field. By default this contains a transform to strip beginning and
       trailing spaces.  Set this attribute to null to skip trimming, or supply a different
       transform.

         trim => { transform => sub {
             my $string = shift;
             $string =~ s/^\s+//;
             $string =~ s/\s+$//;
             return $string;
         } }
         trim => { type => MyTypeConstraint }

       Trimming is performed before any other defined actions.

   Inflation/deflation
       There are a number of methods to provide finely tuned inflation and deflation:

       inflate_method
           Inflate to a data format desired for validation.

       deflate_method
           Deflate to a string format for presenting in HTML.

       inflate_default_method
           Modify the 'default' provided by an 'item' or 'init_object'.

       deflate_value_method
           Modify the value returned by "$form->value".

       deflation
           Another way of providing a deflation method.

       transform
           Another way of providing an inflation method.

       Normally if you have a deflation, you will need a matching inflation.  There are two
       different flavors of inflation/deflation: one for inflating values to a format needed for
       validation and deflating for output, the other for inflating the initial provided values
       (usually from a database row) and deflating them for the 'values' returned.

       See HTML::FormHandler::Manual::InflationDeflation.

Processing and validating the field

   validate_field
       This is the base class validation routine. Most users will not do anything with this. It
       might be useful for method modifiers, if you want code that executed before or after the
       validation process.

   validate
       This field method can be used in addition to or instead of 'apply' actions in custom field
       classes.  It should validate the field data and set error messages on errors with
       "$field->add_error".

           sub validate {
               my $field = shift;
               my $value = $field->value;
               return $field->add_error( ... ) if ( ... );
           }

   validate_method, set_validate
       Supply a coderef (which will be a method on the field) with 'validate_method' or the name
       of a form method with 'set_validate' (which will be a method on the form). If not
       specified and a form method with a name of "validate_<field_name>" exists, it will be
       used.

       Periods in field names will be replaced by underscores, so that the field 'addresses.city'
       will use the 'validate_addresses_city' method for validation.

          has_field 'my_foo' => ( validate_method => \&my_foo_validation );
          sub my_foo_validation { ... }
          has_field 'title' => ( isa => 'Str', set_validate => 'check_title' );

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.