This recipe is compatible with eZ Publish 5.2 / 2013.07

 

Custom tags

XMLText fieldtype supports a limited number of tags in its internal eZXML format to render HTML5. However, it is possible to extend the rendering by implementing custom tags.

As HTML5 rendering in eZ Publish is done through XSLT, you will need to create an XSL stylesheet to extend the rendering.

 

To be able to edit a custom tag from admin interface, you'll still need to register your custom tag in the legacy kernel (at least the configuration part, template not being mandatory for edition).


Register your custom XSL stylesheet

To activate your custom tag rendering, you need to create an XSL stylesheet and to register it properly:

ezpublish:
    system:
        my_siteaccess:
            fieldtypes:
                ezxml:
                    custom_tags:
                        # Adding ezpublish/Resources/my_custom.xsl (priority defaults to 0).
                        - { path: %kernel.root_dir%/Resources/my_custom.xsl }
                        # Adding src/Acme/TestBundle/Resources/another_custom.xsl with priority 10.
                        - { path: %kernel.root_dir%/../src/Acme/TestBundle/Resources/another_custom.xsl, priority: 10 }

Each entry under custom_tags is a hash having the following properties:

path

Absolute path to the XSL to import.

Use %kernel.root_dir% parameter to start from ezpublish/ folder.

priority

Priority of your stylesheet in the sequence of importing. The higher it is, the higher precedence it will have.

In XSL imports, in case of template overrides, the last imported XSL always wins. Hence custom XSL are loaded in reverse priority order.

Example of a custom XSL

The following example shows how to render the YouTube embed custom tag from jvEmbed legacy extension (see also related legacy configuration for content).

Note that all selected attributes are in custom namespace (this is the case for all custom tags attributes in internal eZXML).

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
        version="1.0"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:xhtml="http://ez.no/namespaces/ezpublish3/xhtml/"
        xmlns:custom="http://ez.no/namespaces/ezpublish3/custom/"
        xmlns:image="http://ez.no/namespaces/ezpublish3/image/"
        exclude-result-prefixes="xhtml custom image">

    <xsl:output method="html" indent="yes" encoding="UTF-8"/>
 
    <!-- Template below will match the following custom tag: -->
    <!-- <custom name="youtube" custom:video="//www.youtube.com/embed/MfOnq-zXXBw" custom:videoWidth="640" custom:videoHeight="380"/> -->
    <xsl:template match="custom[@name='youtube']">
        <div class="jvembed jvembed-youtube">
            <iframe>
                <xsl:attribute name="width"><xsl:value-of select="@custom:videoWidth"/></xsl:attribute>
                <xsl:attribute name="height"><xsl:value-of select="@custom:videoHeight"/></xsl:attribute>
                <xsl:attribute name="src"><xsl:value-of select="@custom:video"/></xsl:attribute>
                <xsl:attribute name="frameborder">0</xsl:attribute>
                <xsl:attribute name="allowfullscreen"/>
            </iframe>
        </div>
    </xsl:template>
</xsl:stylesheet>

PHP functions are registered in the XSLTProcessor, so you can use global PHP functions and static method calls to enhance the XSLT process (using php-function and php-functionString XSLT functions, see further info).

However, given this is only for static PHP code, it is only suitable for very simple use cases! For most use cases, where you need to inject some service for your logic, for instance Repository, you'll need to use Pre-Converters instead (see below).

Using Pre-converters

Pre-converters are services that pre-process the internal XML before the XSLT rendering occurs. It can be useful if you need to manipulate the data stored in eZXML.

An example of use is what is done in the EmbedTagBundle for videos : video links are transformed in embed links.

Pre-converters receive the whole DOMDocument object for the current field. So you can easily do XPath queries and do some DOM manipulation against it.

Registering a pre-converter

All pre-converters need to:

 

parameters:
    my.ezxml.pre_converter.class: Acme\TestBundle\XmlText\MyPreConverter
 
services:
    my.ezxml.pre_converter:
        class: %my.ezxml.pre_converter.class%
        arguments: [@someDependency, @someOtherDependency]
        tags:
            - { name: ezpublish.ezxml.converter }
<?php

namespace Acme\TextBundle\XmlText;

use eZ\Publish\Core\FieldType\XmlText\Converter;
use DOMDocument;

class MyPreConverter implements Converter
{
    public function __construct( $someDependency, $someOtherDependency )
    {
        // ...
    }

    /**
     * Does a partial conversion work on $xmlDoc.
     *
     * @param \DOMDocument $xmlDoc
     *
     * @return null
     */
    public function convert( DOMDocument $xmlDoc )
    {
        // Do something on $xmlDoc
        // You can for example walk through the DOM, do XPath queries, add/modify attributes...
    }
}

Overriding existing XSL templates

As XSL stylesheets apply for the whole resulted DOM, you can of course override existing templates. This is where the priority property in configuration takes its sense.

Built-in XSL templates have 0 as priority

 

Consider the following example to switch from usage of <b> to <strong>:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
        version="1.0"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:xhtml="http://ez.no/namespaces/ezpublish3/xhtml/"
        xmlns:custom="http://ez.no/namespaces/ezpublish3/custom/"
        xmlns:image="http://ez.no/namespaces/ezpublish3/image/"
        exclude-result-prefixes="xhtml custom image">
 
    <!-- Original template transforms into <b> -->
    <xsl:template match="strong">
        <strong>
            <xsl:copy-of select="@*"/>
            <xsl:apply-templates/>
        </strong>
    </xsl:template>

</xsl:stylesheet>
ezpublish:
    system:
        my_siteaccess:
            fieldtypes:
                ezxml:
                    custom_tags:
                        # Adding a higher priority to ensure built-in template will be overriden.
                        - { path: %kernel.root_dir%/Resources/strong.xsl, priority: 10 }