add updated post for form type extensions

_posts/2011-11-25-how-to-extend-form-fields-in-symfony2.markdown

@@ -14,6 +14,8 @@ templates:
     {% endblock %}
 ---
 
+**Update: For Symfony2.1 update please take a look at the [updated post].**
+
 In case you have read [the form documentation], you will have noticed, that the example won't work out of the box.
 
 {% highlight jinja %}
@@ -116,5 +118,6 @@ Using `Twitter Bootstrap` this is how it would look like.
 
 ![A form with help messages](/images/2011/11/Symfony2-example-form-with-help-messages.png "A form with help messages")
 
+[updated post]: /2012/11/03/how-to-extend-form-fields-in-symfony2.1.html
 [the form documentation]: http://symfony.com/doc/2.0/cookbook/form/form_customization.html#adding-help-messages
 [form component of Symfony2]: https://github.com/symfony/Form

_posts/2012-11-03-how-to-extend-form-fields-in-symfony2.1.markdown

@@ -0,0 +1,182 @@
+---
+layout: post
+title: "How to extend form fields in Symfony2.1 using extensions"
+excerpt: |
+  This blogpost explains on the example of adding support for the "autocomplete" attribute to widgets how to use form type extensions.
+  It also illustrates changes required when upgrading from Symfony 2.0 to 2.1.
+---
+
+The [previous post] on `FormTypeExtensionInterface` is outdated for the current Symfony version 2.1.
+As requested multiple times, I want to share an updated version of how to create such an extension.
+
+The only main differences between the previous posts state and the current version are:
+
+1. The extensions are now using `Interfaces` instead of implementations (classes).
+2. There are changes on how to setup the available options.
+3. There is no "field" type anymore.
+
+The basic understanding of what those extensions are for are described in [the form documentation] and my [previous post].
+
+Now let's get to the changes from Symfony 2.0 to 2.1 on this matter.
+
+## Interfaces instead of implementations
+
+The first change is the type hinting on `Interfaces` instead of actual classes (implementations).
+PHP will throw you the error, as the methods signature do not match anymore, when updating.
+
+This should be very trivial to fix, you only need to add the `use` statements for the missing interfaces (replacing the `FormBuilder` for example with `FormBuilderInterface`) until PHP is fine with loading the class file.
+
+## The OptionsResolverInterface
+
+A major change is made by using the `OptionsResolverInterface`, which is part of its respective component.
+This resolver deprecates the `getDefaultOptions` method of the `AbstractTypeExtension`.
+
+The `FormTypeExtensionInterface` does not declare this method anymore.
+If you used the interface before instead of the abstract implementation of it, you will at least be notified by PHP on the missing implementation of the `setDefaultOptions` method.
+A very basic implementation of this methods looks like this, and resembles the previous `getDefaultOptions`.
+
+{% highlight php %}
+<?php
+    public function setDefaultOptions(OptionsResolverInterface $resolver)
+    {
+        $resolver->setDefaults(array(
+            'help' => null,
+        ));
+    }
+?>
+{% endhighlight %}
+
+## The field is gone
+
+There is no `FieldType` anymore (well it's deprecated until 2.3).
+There are two places where you have to exchange "field" with "form" and everything is fine again.
+
+1. In the respective tag of the service definition.
+2. The `getExtendedType` method of the extension.
+
+{% highlight yaml %}
+services:
+    form.type_extension.help_message:
+        class: Acme\Bundle\DemoBundle\Form\Extension\HelpMessageTypeExtension
+        tags:
+          - { name: "form.type_extension", alias: "form" }
+{% endhighlight %}
+
+{% highlight php %}
+<?php
+    public function getExtendedType()
+    {
+        return 'form';
+    }
+?>
+{% endhighlight %}
+
+## The HelpMessageTypeExtension
+
+This is the updated version of the `HelpMessageTypeExtension`.
+It resembled the previous behavior as much as possible, although it's not required to do it that way in Symfony 2.1.
+
+{% highlight php %}
+<?php
+
+namespace Acme\Bundle\DemoBundle\Form\Extension;
+
+use Symfony\Component\Form\AbstractTypeExtension;
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\Form\FormView;
+use Symfony\Component\Form\FormBuilderInterface;
+use Symfony\Component\OptionsResolver\OptionsResolverInterface;
+
+class HelpMessageTypeExtension extends AbstractTypeExtension
+{
+    public function buildForm(FormBuilderInterface $builder, array $options)
+    {
+        $builder->setAttribute('help', $options['help']);
+    }
+
+    public function buildView(FormView $view, FormInterface $form, array $options)
+    {
+        $view->vars['help'] = $form->getConfig()->getAttribute('help');
+    }
+
+    public function setDefaultOptions(OptionsResolverInterface $resolver)
+    {
+        $resolver->setDefaults(array(
+            'help' => null,
+        ));
+    }
+
+    public function getExtendedType()
+    {
+        return 'form';
+    }
+}
+?>
+{% endhighlight %}
+
+## The AutocompleteExtension
+
+This extension adds additional HTML attributes to your input fields.
+Those attributes define the type of content the browser should provide when automatically filling the input field.
+See [autocomplete at whatwg] for more details on which types are available.
+
+This version removes the setting of an attribute on the form.
+This is possible, because the `buildView` now retrieves the provided `$options` directly, so no need anymore store the information twice.
+
+{% highlight php %}
+<?php
+
+namespace Acme\Bundle\DemoBundle\Form\Extension;
+
+use Symfony\Component\Form\AbstractTypeExtension;
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\Form\FormView;
+use Symfony\Component\OptionsResolver\OptionsResolverInterface;
+
+class AutocompleteExtension extends AbstractTypeExtension
+{
+    public function buildView(FormView $view, FormInterface $form, array $options)
+    {
+        if (false === $options['autocomplete']) {
+            $options['autocomplete'] = 'off';
+        }
+
+        // It doesn't hurt even it will be left empty.
+        if (empty($view->vars['attr'])) {
+            $view->vars['attr'] = array();
+        }
+
+        if (null !== $options['autocomplete']) {
+            $view->vars['attr'] = array_merge(array(
+                'autocomplete' => $options['autocomplete'],
+                'x-autocompletetype' => $options['autocomplete'],
+            ), $view->vars['attr']);
+        }
+    }
+
+    public function setDefaultOptions(OptionsResolverInterface $resolver)
+    {
+        $resolver->setDefaults(array(
+            'autocomplete' => null,
+        ));
+    }
+
+    public function getExtendedType()
+    {
+        return 'form';
+    }
+}
+?>
+{% endhighlight %}
+
+{% highlight yaml %}
+services:
+    form.type_extension.autocomplete:
+        class: Acme\Bundle\DemoBundle\Form\Extension\AutocompleteExtension
+        tags:
+          - { name: "form.type_extension", alias: "form" }
+{% endhighlight %}
+
+[previous post]: /2011/11/25/how-to-extend-form-fields-in-symfony2.html
+[the form documentation]: http://symfony.com/doc/2.1/cookbook/form/form_customization.html#adding-help-messages
+[autocomplete at whatwg]: http://wiki.whatwg.org/wiki/Autocomplete_Types