In order to display data of our FieldType Field Type from templates, we need to create and register a template for it. You can find documentation about FieldType templates on https://confluence.ez.no/display/EZP/FieldType+template, as well as on https://confluence.ez.no/display/EZP/import+settings+from+a+ importing settings from a bundle.

In a couple words, such a template must:

• extend EzPublishCoreBundle::content_fields.html.twig

• define a dedicated Twig block for the type, named by convention <TypeIdentifier_field>. In our case, eztweet_field

• be registered in parameters

The template: Resources/views/fields/eztweet.tpl

The first thing we will do is create the template. It will basically define the default display of a tweet. Remember that field type templates can be overridden in order to tweak what is displayed and how.

Each FieldType Field Type template receives a set of variables that can be used to achieve the desired goal.   The variable we care about is field, an instance of of eZ\Publish\API\Repository\Values\Content\Field. In addition to its own metadata (id, fieldDefIdentifier, etc...), it exposes the Field Value (Tweet\Value) through the value property.

This would work as a primitive template:  

{% block eztweet_field %}
{% spaceless %}
    {{ field.value.contents|raw }}
{% endspaceless %}
{% endblock %}

...

Even though the above will work just fine, a couple of helpers will help us get something a bit more flexible. The EzPublishCoreBundle::content_fields.html.twig template, where the native FieldType Field Type templates are implemented, provides a couple of helpers: simple_block_field, simple_inline_field and field_attributes. The first two are used to display a field either as a block , or inline. field_attributes makes it easier to use the attr variable , that contains additional (HTML) attributes for the field.

...

First, we need to make our template inherit from content_fields.html.twig. Then, we will create a field_value variable , that will be used by the helper to print out the content inside the markup. And that's it. The helper will use field_attributes to add the HTML attributes to the generated div.

{% block eztweet_field %}
{% spaceless %}
    {% set field_value %}
        {{ field.value.contents|raw }}
    {% endset %}
    {{ block( 'simple_block_field' ) }}
{% endspaceless %}
{% endblock %}

ezpublish:
    global:
        field_templates:
            - { template: "EzSystemsTweetFieldTypeBundle:fields:eztweet.html.twig"}

use Symfony\Component\DependencyInjection\Extension\PrependExtensionInterface;
use Symfony\Component\Yaml\Yaml;

class EzSystemsTweetFieldTypeExtension extends Extension implements PrependExtensionInterface
{
    public function prepend( ContainerBuilder $container )
    {
        $config = Yaml::parse( __DIR__ . '/../Resources/config/ezpublish_field_templates.yml' );
        $container->prependExtensionConfig( 'ezpublish', $config );
    }
}

system:
    default:
        field_templates:
            - {template: "EzSystemsTweetFieldTypeBundle:fields:eztweet.html.twig"}