Renderers

This page explains the concept of renderers, how to configure them and which renderers Magnolia provides out of the box.

Overview

A renderer produces output such as HTML or text based on the template definition, the template script and JCR content.

In summary, a renderer does the following things:

The SPA renderer uses different techniques to render a page.

The rendering process is executed by info.magnolia.rendering.engine.RenderingFilter. The result of the renderer is written to ServletOutputStream and sent to the browser. For further details, see Rendering content.

Magnolia provides the following renderers out of the box:

  • info.magnolia.rendering.renderer.FreemarkerRenderer

  • info.magnolia.module.site.renderer.SiteAwareRendererWrapper

  • info.magnolia.rendering.spa.renderer.SpaRenderer

You can also implement your own custom renderer. To use a renderer, you must configure it either using YAML or in the JCR configuration workspace.

See an overview of differences between FreeMarker and headless templating.

Configuring a renderer

To make a renderer available, you must configure it in the renderers folder of any module either using YAML, or in the JCR configuration workspace.

Once configured, you can:

  • Decorate the renderer definition.

  • Reuse the renderer definition as a base for a new renderer using YAML inherit.

  • Use the YAML include directive if the definition is YAML-based.

View your renderer definitions in the Definitions app.

Definition app render

renderer-test-module/renderers/foobar.yaml
class: info.magnolia.rendering.renderer.FreemarkerRenderer
contextAttributes:
  cms:
    componentClass: info.magnolia.templating.freemarker.Directives
    name: cms
  cmsfn:
    componentClass: info.magnolia.templating.functions.TemplatingFunctions
    name: cmsfn
Property Description

name

The name of the renderer. In JCR it is the node name, in YAML it is the file name.

The renderer name is used to reference a renderer within a template definition.
/test-custom-renderers/templates/pages/test-page.yaml
title: test-page
templateScript: /test-custom-renderers/templates/pages/test-page.ftl
renderType: foobar
Property Description

class

Fully qualified class name. Must implement the info.magnolia.rendering.renderer.Renderer interface.

contextAttributes

A map to register components that are injected into the rendering context. The components can be used within the template scripts with their given names.

     componentClass

The fully qualified class name of the context attribute component.

     name

The name of the component to add to the context. Use this name to reference the component in a template script.

Renderers provided by Magnolia

Magnolia provides a number of renderers out-of-the-box.

Use the default Magnolia renderers as a base. Extend them to define your own new renderers using YAML inherit or similar techniques to reuse the configuration.
Renderer Provided by the module Configuration

FreeMarker renderer

magnolia-rendering

/modules/rendering/renderers/freemarker

Site-aware renderer for FreeMarker

magnolia-site

/modules/site/renderers/site

SPA renderer

pages

/spa-rendering/renderers/spa.yaml

Note that magnolia-rendering is available in every preconfigured Magnolia bundle or webapp, whereas magnolia-site is available in every preconfigured Magnolia bundle or webapp except magnolia-empty-webapp.

FreeMarker renderer

The FreeMarker renderer is used to render pages relying on templates with FreeMarker-based template scripts. The FreeMarker renderer can be considered as the standard Magnolia renderer. It is also the base for the #_site_aware_renderers.

The implementation class is info.magnolia.rendering.renderer.FreemarkerRenderer.

/.magnolia/admincentral#app:configuration:browser;/modules/rendering/renderers:treeview
freemarker:
  class: info.magnolia.rendering.renderer.FreemarkerRenderer
  contextAttributes:
    cms:
      componentClass: info.magnolia.templating.freemarker.Directives
      name: cms
    cmsfn:
      componentClass: info.magnolia.templating.functions.TemplatingFunctions
      name: cmsfn
    imgfn:
      componentClass: info.magnolia.imaging.functions.ImagingTemplatingFunctions
      name: imgfn
    peekfn:
      componentClass: info.magnolia.unfurl.functions.PeekFunctions
      name: peekfn
    resfn:
      componentClass: info.magnolia.modules.resources.templating.ResourcesTemplatingFunctions
      name: resfn
    sitefn:
      componentClass: info.magnolia.module.site.functions.SiteFunctions
      name: sitefn
    damfn:
      componentClass: info.magnolia.dam.templating.functions.DamTemplatingFunctions
      name: damfn
    restfn:
      componentClass: info.magnolia.rest.client.templating.RestTemplatingFunctions
      name: restfn
    ecomfn:
      componentClass: info.magnolia.ecommerce.templating.EcommerceTemplatingFunctions
    searchfn:
      componentClass: info.magnolia.templating.functions.SearchTemplatingFunctions
      name: searchfn
    navfn:
      componentClass: info.magnolia.templating.functions.NavigationTemplatingFunctions
      name: navfn
    catfn:
      componentClass: info.magnolia.module.categorization.functions.CategorizationTemplatingFunctions
      name: catfn
    tourfn:
      componentClass: info.magnolia.demo.travel.tours.TourTemplatingFunctions
      name: tourfn

Some parts of the configuration are added by modules which provide components registered in contextAttributes.

FreeMarker exception handling

FreeMarker exceptions render differently on the author and public instances. On author, FreeMarker exceptions show the stack trace in a yellow block with red text, and on public errors are hidden and logged.

This behavior is controlled by info.magnolia.freemarker.ModeDependentTemplateExceptionHandler registered in /server/rendering/freemarker/templateExceptionHandler. You can extend this class to fine-tune behavior.

FreeMarker security

Magnolia extends FreeMarker’s DefaultMemberAccessPolicy with a configurable list of blacklisted classes. If you want to add more classes to the default configuration, import this YAML bootstrap file into configuration:/server/rendering/freemarker/ and add your entries.

Default configuration
'memberAccessPolicy':
  'class': 'info.magnolia.freemarker.models.ClassBlacklistMemberAccessPolicy'
  'blacklistedClasses':
    'javax.servlet.ServletContext':
      'className': 'javax.servlet.ServletContext'
    'javax.security.auth.Subject':
      'className': 'javax.security.auth.Subject'
    'javax.jcr.Repository':
      'className': 'javax.jcr.Repository'
    'org.apache.jackrabbit.core.data.DataStoreFactory':
      'className': 'org.apache.jackrabbit.core.data.DataStoreFactory'
    'org.apache.jackrabbit.core.RepositoryContext':
      'className': 'org.apache.jackrabbit.core.RepositoryContext'
    'org.apache.jackrabbit.core.fs.FileSystemFactory':
      'className': 'org.apache.jackrabbit.core.fs.FileSystemFactory'
    'org.apache.jackrabbit.core.data.DataStoreFactory2':
      'className': 'org.apache.jackrabbit.core.data.DataStoreFactory'
    'org.apache.jackrabbit.core.query.QueryHandlerFactory':
      'className': 'org.apache.jackrabbit.core.query.QueryHandlerFactory'
    'org.apache.jackrabbit.core.util.db.ConnectionFactory':
      'className': 'org.apache.jackrabbit.core.util.db.ConnectionFactory'
    'javax.servlet.http.HttpSessionBindingListener':
      'className': 'javax.servlet.http.HttpSessionBindingListener'

You can also implement your own freemarker.ext.beans.MemberAccessPolicy.

Rendering single-page applications (SPA)

Currently, the following functionalities are not supported in SPA rendering:

Site-aware renderers

A site-aware renderer resolves the site definition related to the given request and merges the template definition of the requested page with the template prototype from the site definition.

The magnolia-site module adds the sitefn context attribute to the freemarker renderer configuration and configures the site renderer in /modules/site/renderers. Site-aware renderers are implemented by the info.magnolia.module.site.renderer.SiteAwareRendererWrapper class. It is a wrapper that relies on another already existing renderer. It comes with the property wrappedRendererType, which must be configured. The value of this property is the name of the wrapped renderer.

/.magnolia/admincentral#app:configuration:browser;/modules/site/renderers/site:treeview
site:
  class: info.magnolia.module.site.renderer.SiteAwareRendererWrapper
  wrappedRendererType: freemarker

SPA renderer

The SPA (Single-Page Application) renderer produces template annotations, which the Pages app transforms into the green toolbars – editable page elements.

The implementation class is info.magnolia.rendering.spa.renderer.SpaRenderer.

Rendering single-page applications (SPA)

Currently, the following functionalities are not supported in SPA rendering:

JavaScript renderers

Two additional JavaScript libraries are provided by Magnolia to help render SPA pages in the Angular and ReactJS front-end frameworks.

Repository link: https://git.magnolia-cms.com/scm/modules/frontend-helpers.git

npm package names README files

@magnolia/angular-editor

/angular-editor/projects/angular-editor/README.md

@magnolia/react-editor

/react-editor/README.adoc

Others

The renderers described above are the most frequently used Magnolia renderers and cater to many use cases.

The following renderers are used for special cases.

info.magnolia.templating.renderers.NoScriptRenderer

The renderer for definitions without template scripts. Renders ContentMaps from components or component attribute from contextObjects.

info.magnolia.templating.renderers.PlainTextTemplateRenderer

Template renderer for plain text.

info.magnolia.module.resources.renderers.ResourcesBinaryRenderer

Streams the binary data stored in the content or loads it from an arbitrary path.

Creating a custom renderer

To create your own renderer, extend info.magnolia.rendering.renderer.AbstractRenderer. This convenience class supports typical functionality such as setting context attributes and executing a rendering model. It sets up the context by providing the following objects:

  • content

  • def

  • state

  • model

  • actionResult

See mustache-rendering for a detailed example.
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