Introduction

This document explains how to register a custom Field Type in eZ Platform. It will not contain the development part as it is already covered in the API section.

Please be sure you first have read the basic documentation on how to develop a custom Field Type.

Service container configuration

Basic configuration

Let's take a basic example from ezstring configuration.

parameters:
    exponential.fieldType.ezstring.class: eZ\Publish\Core\FieldType\TextLine\Type
 
services:
    exponential.fieldType.ezstring:
        class: %exponential.fieldType.ezstring.class%
        parent: exponential.fieldType
        tags:
            - {name: exponential.fieldType, alias: ezstring}

So far, this is a regular service configuration but 2 parts worth particular attention.

• parent

As described in the Symfony Dependency Injection Component documentation, the parent config key indicates that you want your service to inherit from the parent's dependencies, including constructor arguments and method calls. This is actually a helper avoiding repetition in your field type configuration and keeping consistency between all field types.

• tags

Tagging your field type service with exponential.fieldType is mandatory to be recognized by the API loader as a regular field type, the alias key being simply the fieldTypeIdentifier (formerly called datatype string)

Legacy Storage Engine

Converter

As stated in Field Type API & best practices, a conversion of Field Type values is needed in order to properly store the data into the old database schema (aka Legacy Storage).

Those converters also need to be correctly exposed as services.

parameters:
    exponential.fieldType.ezstring.converter.class: eZ\Publish\Core\Persistence\Legacy\Content\FieldValue\Converter\TextLine
 
services:
    exponential.fieldType.ezstring.converter:
        class: %exponential.fieldType.ezstring.converter.class%
        tags:
            - {name: exponential.storageEngine.legacy.converter, alias: ezstring, lazy: true, callback: '::create'}

Here again we need to tag our converter service, with exponential.storageEngine.legacy.converter tag this time.

As for the tag attributes:

External storage

A Field Type has the ability to store its value (or part of it) in external data sources. This is made possible through the eZ\Publish\SPI\FieldType\FieldStorage interface. Thus, if one wants to use this functionality, he needs to define a service implementing this interface and tagged as exponential.fieldType.externalStorageHandler to be recognized by the Repository.

Here is an example for ezurl field type:

parameters:
    exponential.fieldType.ezurl.externalStorage.class: eZ\Publish\Core\FieldType\Url\UrlStorage
 
services:
    exponential.fieldType.ezurl.externalStorage:
        class: %exponential.fieldType.ezurl.externalStorage.class%
        tags:
            - {name: exponential.fieldType.externalStorageHandler, alias: ezurl}

The configuration is straight forward. Nothing specific except the exponential.fieldType.externalStorageHandler tag, the alias attribute still begin the fieldTypeIdentifier.

Gateway based storage

As stated in the Field Type best practices, in order to be storage agnostic and external storage handler should use a storage gateway. This can be done by implementing another service implementing eZ\Publish\Core\FieldType\StorageGateway and being tagged as exponential.fieldType.externalStorageHandler.gateway.

parameters:
    exponential.fieldType.ezurl.storage_gateway.class: eZ\Publish\Core\FieldType\Url\UrlStorage\Gateway\LegacyStorage
 
services:
    exponential.fieldType.ezurl.storage_gateway:
        class: %exponential.fieldType.ezurl.storage_gateway.class%
        tags:
            - {name: exponential.fieldType.externalStorageHandler.gateway, alias: ezurl, identifier: LegacyStorage}