Developing and rendering custom content blocks

This page describes how to define and render custom content blocks that can be grouped to form content compositions in implementations of the Content editor.

Compatibility note

Custom content editor and block definitions created in the Magnolia 5 UI framework must be migrated.

Block types

The Content editor provides predefined block types that you can use in your custom content editor app:

text - Compared to TextFieldDefinition, the text block implements a special LightRichTextFieldDefinition class, which features basic text formatting functions:

Light RichText Field block with control box

templateId: content-editor:blocks/text
icon: text-block
label: Text
block:
  implementationClass: info.magnolia.editor.field.LightRichTextFormView
  properties:
    text:
      class: info.magnolia.editor.field.LightRichTextFieldDefinition
      linkableApps:
        - pages-app
        - dam-chooser

image - Configured using the ordinary 6 UI damLinkField and textField field types:

templateId: content-editor:blocks/image
icon: file-image
label: Image
block:
  properties:
    image:
      $type: damLinkField
      label: Image
      placeholder: Add image...
      buttonSelectNewLabel: Select new...
    imageAltText:
      label: Alt text
      $type: textField
      placeholder: Add alt text...
    imageCaption:
      label: Caption
      placeholder: Add caption...
      $type: textField
    imageCredit:
      label: Credits
      placeholder: Add credits...
      $type: textField

externalLink - Utilizing the PeekFieldDefinition class from the Magnolia Link Unfurl Module, a submodule in the Content Editor module.

templateId: link-unfurl:components/externalLink
icon: embed
label: Embed content
block:
  properties:
    url:
      class: info.magnolia.unfurl.ui.PeekFieldDefinition
      label: Embedded content
      validators:
        url:
          class: info.magnolia.unfurl.ui.UrlValidatorDefinition
          errorMessage: link-unfurl.components.externalLink.tabUrl.url.validation.errorMessage

video - A combination of the following 6 UI field types: checkBoxField, comboBoxField, damLinkField, expandingTextField, radioButtonGroupField, switchableField and textField.

Demo block types

The Magnolia Demo decorates the default Stories app and provides two additional block types you can use:

date
tour

These block types implement the 6 UI dateField and linkField, respectively. To see these blocks, you must have the Magnolia demo modules installed.

Defining a custom content block

To define a custom block, use a YAML definition file and apply the BlockDefinition class of the Content editor module.

Create a YAML file in the blocks folder of your module and add the following required definition elements.

class: info.magnolia.block.BlockDefinition (1)
templateId: <module-name>:<the-path-to-the-block-relative-to-the-module> (2)
icon: <icon-name>
label: <i18n-label>
block: (3)
  itemProvider:
    $type: jcrBlockGetIndexedChildNode
  properties:
    field1:
      <field1-property1>
      <field1-property2>
    field2:
      <field2-property1>
      <field2-property2>
      etc.

1	The `info.magnolia.block.BlockDefinition` class.
2	The `templateId` of your block.
3	A `block` node, with a list of fields the content block consists of. Use the properties in the same way as the properties for the `CompositeFieldDefinition`.

Provide a template definition file and a template script for your block in the templates/blocks subfolder of your module.
Optionally, in the i18n folder of your module, provide a file with i18n keys for labels and descriptions of the block’s fields.

Creating a custom block with Magnolia CLI

`create-block`

In this CLI version, the block prototypes are not yet compatible with the migrated (6 UI) Content Editor module and Stories app.

The block definition created will be based on the 5 UI info.magnolia.editor.block.stock.FieldSetBlockDefinition.

If you want to use the 6 UI-native block definition (based on info.magnolia.block.BlockDefinition), you have to migrate the definition created by the command.

This command creates:

A block definition YAML file.
A template definition YAML file.
A freemarker template script.

The command succeeds only if the current directory (or the directory defined by the optional -p <path> parameter) is a light module with a minimal folder structure.

The files which are created when executing this command are built from the files in the prototypes folder of your configuration. The files contain some standard code with some commonly used properties. This is generally a good starting point to build a block.

Usage

mgnl create-block <blockName> [options]

Parameters

Parameter Description

Parameter	Description
`<blockName>`	required The name of the new block definition. The block name cannot contain spaces.

<blockName>

required

The name of the new block definition. The block name cannot contain spaces.

Options

Short form Long form Description

Short form	Long form	Description
`-p <path>`	`--path <path>`	optional The path to the light module to add the new block to. If you do not specify a path, you must run the command from an existing light module folder.
`-P <name>`	`--prototype <name>`	optional The name of the prototype variant to create the block.

-p <path>

--path <path>

optional

The path to the light module to add the new block to.

If you do not specify a path, you must run the command from an existing light module folder.

-P <name>

--prototype <name>

optional

The name of the prototype variant to create the block.

Example

mgnl create-block my-block

If you do not use the -p <path> option, you must run the command from an existing light module folder.

Rendering blocks in a FreeMarker script

This section explains how to render block content in a page or a component template.

The `cms:block` directive

The Content editor module provides cms:block, a Magnolia FreeMarker directive for fetching and rendering block elements.

The directive expects a node of the type mgnl:block as argument, identifies the template definition of the block and calls the associated template script.

[#assign blocks = cmsfn.children(articleContent, "mgnl:block") /]
  [#list blocks as block]
    [@cms.block content=block /]
  [/#list]

Examples of block rendering

The examples show how to render blocks within a template script of a page or component template. Using the Magnolia directive cms.block, the template script of the block is executed during the rendering of the page or component.

Get story content:

[#assign articleContent = cmsfn.contentById(content.article, "") /]
Get the blocks for that story:
[#assign blocks = cmsfn.children(articleContent, "mgnl:block") /]
Retrieve all blocks for a piece of content:
```
[#if articleContent?hasContent]
  [#assign blocks = cmsfn.children(articleContent, "mgnl:block") /]
  [#list blocks as block]
    [@cms.block content=block /]
  [/#list]
[/#if]
```
Line 4: The Magnolia directive cms.block ensures that the template script associated to the passed block is called to render the block content.

Retrieve two blocks, for instance to display an excerpt of a story in a list:

[#if articleContent?hasContent]
  [#assign blocks = cmsfn.children(articleContent, "mgnl:block") /]
  [#list blocks as block]
    [#if block?index == 2]
      [#break]
    [/#if]
    [@cms.block content=block /]
  [/#list]
[/#if]

Line 7: The Magnolia directive cms.block calls the template script associated to the passed block content.

Content internationalization (i18n)

Internationalization (i18n) of content is supported since version 2.1 of the Content Editor module. Block definitions and data structures created in the older versions of the module must be migrated.

Compatibility of content and block definitions

Flat vs nested content structure

The data model has changed for internationalized stories. Whereas in versions 1.3.x and 2.0.x of the module, the mgnl:block elements are stored in a flat node structure,

stories
└── story1
    ├── 0
    └── 1

in the i18n-supported version (2.1 and higher), the nodes are locale-nested under intermediate nodes of type mgnl:contentNode, named blocks_de and blocks in this example:

stories
└── story1
    └── blocks_de
    │   ├── 0_de
    │   └── 1_de
    └── blocks
        ├── 0
        └── 1

This must be reflected in your MultiJcrBlockDefinition, where you need to add and enable the i18n property.

Instead of the CurrentItemProvider, the CompatibleBlockProvider is set as the default provider, which can resolve both flat and nested block nodes. You do not need to declare it in your block definition.

Example definition

blocks:
  label: Blocks
  $type: multiJcrBlock
  i18n: true
  blocks:
    - text

This applies only to the 2.0.x block definitions. Block definitions created for version 1.3.x (5 UI) of the module are not compatible with the 2.1 version and must be fully migrated.

Migrating content

There are two ways you can migrate the non-i18n blocks to the i18n-compatible hierarchy: using a version handler or a Groovy script.

We strongly recommend you have the latest version of the Content Editor before migrating your content.

In versions prior to 2.1.3, the MigrateBlockToIntermediateParentTask doesn’t preserve the order of nodes when migrating to the latest version. Running this task can actually reorder the nodes to an incorrect state.

Version handler

When upgrading the Stories app submodule to version 2.1 or higher, all block nodes in the stories workspace will be moved to intermediate nodes, see the MigrateBlockToIntermediateParentTask task.

Groovy script

You can run the migration task in the Groovy app, especially in case a block node is stored in another workspace.

Example Groovy script

import info.magnolia.editor.setup.MigrateBlockToIntermediateParentTask
import info.magnolia.module.InstallContextImpl
import info.magnolia.module.ModuleRegistryImpl
import info.magnolia.objectfactory.Components
import javax.jcr.Session


Session session =  MgnlContext.getJCRSession("stories");
task = new MigrateBlockToIntermediateParentTask("stories", "/", "blocks");
task.execute(Components.newInstance(InstallContextImpl.class));
session.save();

The parameters in the MigrateBlockToIntermediateParentTask:

stories - workspace name
/ - path
blocks - name of the intermediate node, the name of the multiJcrBlock field.