Symfony twig how to add class to a form row - symfony

Question

I am building a project in Symfony 2.3 using Twig. I want to add a class to the form row block. I am using a form theme file which contains:
{% block form_row %}
<div class="form-row">
{{ form_label(form) }}
{{ form_widget(form) }}
{{ form_errors(form) }}
</div>
{% endblock %}
Now some of my form rows I want to add an extra class form-row-split. I can't figure out how to do this properly. The way I have it almost-working is:
{% block form_row %}
{% set attr = attr|merge({'class': 'form-row' ~ (attr.class is defined ? ' ' ~ attr.class : '') ~ (errors|length > 0 ? ' error' : '')} ) %}
<div {{ block('widget_container_attributes') }}>
{{ form_label(form) }}
{{ form_widget(form) }}
{{ form_errors(form) }}
</div>
{% endblock %}
(Note, I've left the error class logic in there too as that needs to stay).
Then in the form builder:
$builder
->add('first_name', 'text', array(
'attr' => array(
'class' => 'form-row-split'
)
));
This almost works but it adds this class everywhere and also adds the widget id to the row!
<div id="myform_first_name" class="form-row form-row-split">
<label for="myform_first_name">First name</label>
<input id="myform_first_name" class="form-row-split" type="text" name="myform[first_name]">
</div>
I can think of a few potential solutions but none of them are pretty or straight forward. Surely there must be a simple way of doing this?

Answer 1

There is a fairly simple solution to this problem actually. I just needed a form type extension to extend the base form type to allow an extra available option: http://symfony.com/doc/2.3/cookbook/form/create_form_type_extension.html
Following through the example in the docs, I created a new form type extension:
// src/Acme/FrontendBundle/Form/Extension/FormTypeExtension.php
namespace Acme\FrontendBundle\Form\Extension;
use Symfony\Component\Form\AbstractTypeExtension;
use Symfony\Component\Form\FormInterface;
use Symfony\Component\Form\FormView;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
/**
* Class FormTypeExtension
* #package Acme\FrontendBundle\Form\Extension
*/
class FormTypeExtension extends AbstractTypeExtension
{
/**
* Extends the form type which all other types extend
*
* #return string The name of the type being extended
*/
public function getExtendedType()
{
return 'form';
}
/**
* Add the extra row_attr option
*
* #param OptionsResolverInterface $resolver
*/
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'row_attr' => array()
));
}
/**
* Pass the set row_attr options to the view
*
* #param FormView $view
* #param FormInterface $form
* #param array $options
*/
public function buildView(FormView $view, FormInterface $form, array $options)
{
$view->vars['row_attr'] = $options['row_attr'];
}
}
Then I registered the service in my bundle...
<!-- Form row attributes form extension -->
<service id="acme.form_type_extension" class="Acme\FrontendBundle\Form\Extension\FormTypeExtension">
<tag name="form.type_extension" alias="form" />
</service>
Since every widget extends the base form type this then allows me to pass this new row_attr option through on any field, eg:
$builder
->add('first_name', 'text', array(
'row_attr' => array(
'class' => 'form-row-split'
)
));
Then the twig overrides to make use of the new row_attr option:
{% block form_row %}
<div {{ block('form_row_attributes') }}>
{{ form_label(form) }}
{{ form_widget(form) }}
{{ form_errors(form) }}
</div>
{% endblock form_row %}
{% block form_row_attributes %}
{% spaceless %}
{% for attrname, attrvalue in row_attr %}{{ attrname }}="{{ attrvalue }}" {% endfor %}
{% endspaceless %}
{% endblock form_row_attributes %}
And it's done!
(For completeness, my full twig override still merges in the form-row and error classes in like so:
{% set row_attr = row_attr|merge({'class': 'form-row' ~ (row_attr.class is defined ? ' ' ~ row_attr.class : '') ~ (errors|length > 0 ? ' error' : '')} ) %}
.. but thats not really necessary for answering my own question :P )

Answer 2

Docs say: you always able to pass attr to rendered element:
{{ form_start(form, {'attr': {'class': 'your-class'}} ) }}
{{ form_label(form, {'attr': {'class': 'your-class'}}) }}
{{ form_widget(form, {'attr': {'class': 'your-class'}}) }}
{{ form_errors(form, {'attr': {'class': 'your-class'}}) }}
{{ form_end(form) }}

Answer 3

Below is a clone of answer by #lopsided but with changes reflecting latest Symfony structure changes (v. 2.7+):
There is a fairly simple solution to this problem actually. I just needed a form type extension to extend the base form type to allow an extra available option: http://symfony.com/doc/master/form/create_form_type_extension.html
Following through the example in the docs, I created a new form type extension:
// src/Acme/FrontendBundle/Form/Extension/FormTypeExtension.php
namespace Acme\FrontendBundle\Form\Extension;
use Symfony\Component\Form\AbstractTypeExtension;
use Symfony\Component\Form\FormInterface;
use Symfony\Component\Form\FormView;
use Symfony\Component\Form\Extension\Core\Type\FormType;
use Symfony\Component\OptionsResolver\OptionsResolver;
/**
* Class FormTypeExtension
* #package Acme\FrontendBundle\Form\Extension
*/
class FormTypeExtension extends AbstractTypeExtension
{
/**
* Extends the form type which all other types extend
*
* #return string The name of the type being extended
*/
public function getExtendedType()
{
return FormType::class;
}
/**
* Add the extra row_attr option
*
* #param OptionsResolver $resolver
*/
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults(array(
'row_attr' => []
));
}
/**
* Pass the set row_attr options to the view
*
* #param FormView $view
* #param FormInterface $form
* #param array $options
*/
public function buildView(FormView $view, FormInterface $form, array $options)
{
$view->vars['row_attr'] = $options['row_attr'];
}
}
Then I registered the service in my bundle...
<!-- Form row attributes form extension -->
<service id="acme.form_type_extension" class="Acme\FrontendBundle\Form\Extension\FormTypeExtension">
<tag name="form.type_extension" alias="form" extended_type="Symfony\Component\Form\Extension\Core\Type\FormType" />
</service>
Since every widget extends the base form type this then allows me to pass this new row_attr option through on any field, eg:
$builder
->add('first_name', TextType:class, [
'row_attr' => [
'class' => 'form-row-split'
]
]);
Then the twig overrides to make use of the new row_attr option:
{% block form_row %}
<div {{ block('form_row_attributes') }}>
{{ form_label(form) }}
{{ form_widget(form) }}
{{ form_errors(form) }}
</div>
{% endblock form_row %}
{% block form_row_attributes %}
{% spaceless %}
{% for attrname, attrvalue in row_attr %}{{ attrname }}="{{ attrvalue }}" {% endfor %}
{% endspaceless %}
{% endblock form_row_attributes %}
And it's done!
(For completeness, my full twig override still merges in the form-row and error classes in like so:
{% set row_attr = row_attr|merge({'class': 'form-row' ~ (row_attr.class is defined ? ' ' ~ row_attr.class : '') ~ (errors|length > 0 ? ' error' : '')} ) %}
.. but thats not really necessary for answering my own question :P )

Answer 4

What I did was simpler (though maybe a bit less clean?).
Pass the class for the form row via a field's "data" attribute :
// template.html.twig
{{ form_start(form) }}
{{ form_row(form.field, {'attr': {'data-row-class': 'my-row-class'} }) }}
{{ form_end(form) }}
And then handle it in the form theme template this way :
// form-theme.html.twig
{% block form_row -%}
{% set row_class = attr['data-row-class'] | default('') %}
<div class="{{ row_class }}">
{{- form_label(form) -}}
{{- form_widget(form) -}}
{{- form_errors(form) -}}
</div>
{%- endblock form_row %}
Which gives this :
<form name="formName" method="post">
<div class="my-row-class">
<label for="formName_field">Field label</label>
<input type="text" id="formName_field" name="formName[field]" data-row-class="my-row-class">
</div>
</form>