/ 
Data-MuForm-0.02
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/ Data::MuForm::Manual::Defaults

NAME

Data::MuForm::Manual::Defaults - form defaults documentation

VERSION

version 0.02

SYNOPSIS

Manual Index

How to set defaults for your fields.

Defaults

Defaults for form fields come from a number of different places. The simplest way to set a field's default is on the field definition:

has_field 'foo' => ( type => 'Text', default => 'my_foo' );
has_field 'select_many' => ( type => 'Multiple', default => [1, 2, 3] );

You can also set the default for a field with a method in the form with the name 'default_<field_name>', where any periods in the field name are replaced with underscores.

has_field 'foo';
sub default_foo { 'my_default' }

Or a method set with 'methods':

has_field 'foo' => ( methods => { default => \&my_default } );
sub my_default { 'my_default' }

For forms where you pass in a 'model' (usually a database row object), the values in that object will be used preferentially as defaults; if an accessor exists in the 'model' object, then the defaults in a field definition won't be used.

$form->process( model => $row, params => {} );

You can provide some defaults from the model and some from 'init_values'. If an accessor doesn't exist in the model, init_values will be used.

$form->process( model => $row, init_values => $init_values, params => {} );

If you provide an empty row object for 'create' type actions, the row is not used for defaults (unless you override the 'use_model_for_defaults' sub), so you can provide defaults in the init_values.

$form->process( model => $empty_row, init_values => $init_values,  params => {} );

Note: Do NOT set select field defaults by explicitly setting 'selected' or 'checked' in the options. It will not work properly. Use one of the default methods discussed above.

Defaults when processing params

Normally when a form is posted, the params will contain all the values that are necessary to fill in the form. However, when a form is used in an API-like fashion, such as complex search forms, sometimes it is convenient to only provide particular params and let the others use defaults. If there is a default provided for a non-submitted param (except checkboxes and selects) it will be used to fill-in-the form unless the 'skip_fields_without_input' flag has been set.

Query parameters for defaults

If you have a posted form and also some query parameters, it generally doesn't work well to provide them both as 'params', because it will confuse the issue of whether the form has been submitted or not, and you risk getting doubled up parameters. Using init_values for the query parameters may work in that case. You can also explicitly set the 'submitted' flag on the process call.

$form->process( submitted => ( $c->req->method eq 'POST' ), params => $c->req->params );

Note that in Catalyst, there are 'query_parameters' and 'body_parameters'. The 'parameters' contains both 'query_parameters' and 'body_parameters'. Other web frameworks probably have similar distinctions.

AUTHOR

Gerda Shank

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.