Template scripts

A template script renders output. Typically that output is HTML. The script is written in a templating language such as FreeMarker or JSP. The script instructs the renderer where to place the content on the page and contains placeholders for content attributes such as headings and images.

Scripting languages and renderers

Magnolia provides renderers for Freemarker and JSP out of the box. You can choose the language you prefer. You can even mix languages on the same site, using Freemarker in some templates and JSP in others.

Freemarker

At Magnolia we prefer Freemarker for its flexibility, cleaner syntax and better error reporting but also because it does not depend on the file system. Templates do not have to be extracted to the file system. This means you can store them in the repository and access like any other resources, apply version control if you wish, and add custom properties and metadata.

Example: Render the page title, or render the name if no title exists.

<h3>${content.title!content.@name}</h3>

Here are some of the benefits that Freemarker offers:

• It is a general templating language and not bound to any Java context.
• Provides basic directives such as [if], [else] and [list].
• Has a large set of built-ins.
• Can call public methods of any Java object and any returned object.
• Does not need to be rendered in the request/response context.
• Provides direct access to node objects (beans).
• Can directly iterate any content collections that extend a Java list.
• Strict null value handling leads to stable templates.
• Allows the use of JSP taglibs if required.

JSP

JSP stands for JavaServer Pages. It is an extension of Java Servlet technology for combining Java server-side programs and HTML.

Example: Render the page title or the name if no title exists.

<h3>
<c:choose>
    <c:when test="${not empty content.title}">${content.title}</c:when>
    <c:otherwise>${content['@name']}</c:otherwise>
</c:choose>
</h3>

Other languages

You can also use another templating language. Some sites use Apache Velocity, for example. If a renderer for your language is available, you can most likely incorporate it into Magnolia. This allows you to use a templating language that you are already familiar with.

Renderer configuration

FreemarkerRenderer and  JspRenderer are configured in /modules/rendering/renderers/freemarker and /jsp.

The STK defines its own renderer  STKRenderer configured in /modules/standard-templating kit/rendering/renderers/stk.

The renderType property in page, area and component definitions defines the template renderer to use. For STK templates the type is stk.

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 in preview mode errors are hidden and logged.

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

Loading scripts

The system can load Freemarker scripts from three places in this order:

1. Filesystem of the webapp. You can place a script file in /<CATALINA_HOME>/webapps/<contextPath>/templates folder.
2. templates workspace. The template needs to be enabled to be considered.
3. Web application's classpath. This is where default STK templates are located. Best practice is to package scripts inside the module JAR. A module JAR resides in the classpath so the system finds it.

Template loaders

Freemarker template loaders are configured in /server/rendering/freemarker/templateLoaders/jcr and /webapp:

• LazyWebappTemplateLoader loads templates from the webapp folder by default. If no matching template is found it will be loaded from the classpath.
• JcrRepoTemplateLoader that allows template loading from the repository. This loader is included in the In-place Templating module.
• LazyFileTemplateLoader allows you to load templates from an arbitrary location on the file system.

You can also write your own custom template loader if needed.

Installing scripts into the repository

In order to edit template scripts in the repository, install them into the templates workspace. This is useful for prototyping or developing but it only works with FreeMarker scripts. The scripts become editable in Templating Kit > Templates.

Add a   TemplatesInstallTask into your module version handler. Here is an example from the Standard Templating Kit module (Git):

import info.magnolia.module.inplacetemplating.setup.TemplatesInstallTask;
 
// Install scripts when the module is installed for the first time.
@Override
protected List<Task> getExtraInstallTasks(InstallContext ctx) {
	final List<Task> tasks = new ArrayList<Task>();
	tasks.addAll(super.getExtraInstallTasks(ctx));
	tasks.add(new TemplatesInstallTask("/templating-kit/.*\\.ftl", true));@Override

// Reinstall scripts when the module is updated.
@Override
protected List<Task> getDefaultUpdateTasks(Version forVersion) {
	final List<Task> tasks = new ArrayList<Task>();
	tasks.addAll(super.getDefaultUpdateTasks(forVersion));
	tasks.add(new TemplatesInstallTask("/templating-kit/.*\\.ftl", true));
	return tasks;
	}

Editing scripts in the repository

To edit a template script in the repository:

1. Go to Templating Kit > Templates.
2. Create a template script or edit an existing one. To override a script that would normally be loaded from the classpath, replicate the folder hierarchy. For example, the STK main.ftl (Git) script is in a /templating-kit/pages folder inside the module JAR. Creating the matching folders in the repository allows the repository script override the classpath script.
3. Check the Enable template checkbox.
4. Optional: If you customize a default template script, such as one of the STK scripts, clear the Automatic update box. This ensures that your customizations are not lost when the module is updated. If the box is checked, the script will be replaced with a newer version during module update. 

STK scripts

STK template scripts are in the classpath of the webapp. Copies are editable in-place in Templating Kit > Templates in AdminCentral. STK scripts are written in FreeMarker.

The scripts are stored in child folders of the /templating-kit folder:

• components contains component templates sorted by component type.
• pages contains the main page script and area scripts in subfolders.

This structure follows the template prototype structure. Area templates referenced in the template prototype are stored in the global folder.

main script

main is the the master page script (Git). It is a good starting point to understand the system. It initializes the page editor on the author instance using the @cms.init directive. It also contains the logic to set the body class and body ID.

The main script calls areas to render themselves using the @cms.area directive. It renders the navigation using the #include directive. The main script wraps the areas in three div elements that creates a flexible page grid.

Area scripts

See STK areas for descriptions of STK area scripts.

Directives

Key templating features are available as directives in the Magnolia tag library. Directives are quick to type but can render complex output.

Standard Freemarker directives

Here are the most useful Freemarker directives with sample code:

if, else and elseif

Common operators ( &&, ||, !, ==, !=, >, <, >=, <= ) are supported

Boolean test

[#if content.header?has_content]
   <h1>${content.header}</h1>
[#else]
   DO_SOMETHING_ELSE
[/#if]

[#if content.imageLocation == "top"]
   …
[/#if]

[#if content.date?has_content]
   ${content.date?time?string.short}
[#elseif content.endDate?has_content]
   ${content.endDate?time?string.short}
[#else]
   No date is set!
[/#if]

list

Can iterate over any collection that extends a Java collection.

[#list model.getSomeList() as elem]
   <li>${elem.title!}</li>
[/#list] 

assign

Assign allows you to define variables. Any object except null can be passed to a variable.

[#assign title = content.title!content.@name]
[#assign hasDate = content.date?has_content]
[#assign dateShort = content.date?time?string.short]
[#assign events = model.events]
[#assign stringgy = "Some direct string data"]

include

The include directive includes a Freemarker template script. .

[#include "/templating-kit/templates/content/myScript.ftl"]

macros

Macros allow you to reuse snippets of Freemarker code. See Templating Kit > Templates /templating-kit/components/macros for examples used in the STK.

[#macro test foo bar="Bar" baaz=-1]
    Test text, and the params: ${foo}, ${bar}, ${baaz}
[/#macro]
[@test foo="a" bar="b" baaz=5*5-2/]
[@test foo="a" bar="b"/]
[@test foo="a" baaz=5*5-2/]
[@test foo="a"/]

Custom Magnolia directives

Magnolia provides the following custom directives:

• cms:init renders all the "top matter" in a page HTML and the main bar.
• cms:area renders an area.
• cms:component renders a component

For Freemarker, these directives are implemented by the Directives class. This class is configured in /modules/rendering/renderers/freemarker/contextAttributes/cms/componentClass.

For JSP, the directives are provided by the Templating JSP module.

The directive syntax differs slightly depending on the templating language. Freemarker directives start with the # character in the case of standard directives and with the @ character for custom directives. All directives in the Magnolia cms tag library start with @. What follows is the tag library name such as cms, a dot character, the name of the macro, and any parameters. In JSP the limiting characters are different.

Syntax:

[@<tag library>.<macro> <parameter>=<value> /]

Freemarker example: Render a component

[@cms.component content=component /]

JSP example: Render a component

<cms:component content="${component}"/>

cms:init

The cms.init directive initializes the page editor and renders the top bar. The InitElement class embeds the JavaScript and CSS needed to edit pages on the author instance. The output goes in the <head> element in the page HTML.

Example:

[@cms.init /]

cms:area

The cms:area directive ( AreaDirective ) renders an area and any components inside it. The area toolbar allows editors to add components inside the area. Available components are configured in the area definition.

Example:

[@cms.area name="main"/]

The directive references an area by its name. The area name is the content node that contains the area definition such as main, footer or stage.

The result on the page is an area bar, a start marker, an optional placeholder box, and an end marker. The value of the title property in the area definition is rendered on the bar. When an editor clicks the placeholder they can add components inside the area.

If the area definition contains a templateScript property then the referenced script renders the area. If no script is given then the following default scripts are used instead:

Area type single

[@cms.component content=component /]

Area type list

[#list components as component]
   [@cms.component content=component /]
[/#list]

cms:component

The cms:component directive ( ComponentDirective ) renders a component. The content attribute defines what content the component edits. This tag is commonly used inside the list directive to loop through the components in a collection.

The content to render, and possibly edit in case of an editable component, is passed in the content attribute. On the author instance the directive renders a component toolbar. The value of the title property in the component definition is rendered on the bar.

Example:

[#list components as component ]
   [@cms.component content=component /]
[/#list]

Common directive attributes

The following attributes can be passed with any directive. They define which content the element created by the directive should work on.

Content attribute

The content attribute tells a script which content node it should operate on. Scripts typically operate on the "current" content node. For a page-level script the current node is the page, for an area-level script the current node is the area, and for a component-level script the current node is the component. However, there are cases where you want the script to operate on a different content node. This is where the content attribute comes handy.

For example, the intro area has no content of its own. It doesn't contain any components either since it is of type noComponent. The area operates on page content instead. It edits and renders the page title and abstract. We achieve this by using the content attribute.

In the main.ftl script we tell the main area "You should operate on the current content node, which is a page because I am a page-level script".

<div id="wrapper-3">
    [@cms.area name="platform"/]
    [@cms.area name="main" content=content/]
    [@cms.area name="extras"/]
</div>

In the mainArea area script we again pass the same instruction down to the intro area: "You should operate on the current content node which is (still) the page".

<div id="main" role="main">
    [@cms.area name="breadcrumb" content=content/]
    [@cms.area name="intro" content=content/]
    [@cms.area name="opener"/]
    [@cms.area name="content"/]
</div><!-- end main -->

Now the intro area edits page content. Although the intro area resides inside the main area div element on the page, the title and the abstract really belong to the page. They are the page's properties, not the area's. So it makes sense to store those properties under the page node in the content structure.

Workspace attribute

The workspace attribute tells the directive which workspace of the magnolia JCR repository the content resides in. This is almost always the website workspace and defaults to website automatically if the current content resides in the website workspace.

Example of directive rendering

Here is an example how directives are rendered on the page.

1. The main script contains a cms.init directive which creates the toolbar at the top of the page.
2. The cms.area directive calls an area to be rendered. The directive identifies the area by name, in this case extras. If the area has child areas you need a separate script which calls the children to be rendered. However, if the area contains only components you don't need an area script.
3. The footer of the page is also rendered with an cms.area directive. This area does not have child areas, only components.

Adding your own directives

You can add your own directives. They make Java methods and functions in your own classes available to template scripts:

1. Write and compile your Java class as you normally would.
2. Copy the class file to WEB-INF/classes folder of your Magnolia web application.
3. In AdminCentral, go to /modules/rendering/renderers/freemarker/contextAttributes.
4. Under /contextAttributes, create a content node such as myClass. Name it after the purpose of your class.
5. Under myClass, create two data nodes:
• componentClass and set its value to the fully-qualified name of the class you placed in WEB-INF/classes.
• name and set the value to myClass.

This allows you to access all the static methods in myClass from templates using the ${myClass.myMethod()} Freemarker syntax.

Templating functions

TemplatingFunctions  includes useful methods that you can use in your templates. The methods are exposed as cmsfn. The decode method that removes escaping of HTML on properties is is an example and the snippet below shows its use in the stkTextImage component script.

[#if content.text?has_content]
   ${cmsfn.decode(content).text}
[/#if]

STKTemplatingFunctions  makes additional methods available for use in STK templates. The methods are exposed as stkfn. The snippet below from the promos component script contains two examples: abbreviateString and getAssetVariation.

[#assign text = stkfn.abbreviateString(text, 80)]
[#assign image = model.image!]
[#if image?has_content && !hideTeaserImage]
    [#assign imageLink = stkfn.getAssetVariation(image, "promo").link]

The templating functions classes are configured for each renderer in /<module>/rendering/renderers/<renderer>/contextAttributes/<tag library>. Note that the <tag library> content node and the value of the name data node matches the syntax used to expose the methods in scripts.

Freemarker built-ins

FreeMarker provides a powerful set of built-ins. These are used for basic manipulation of data and no Java code is necessary. Built-ins are used with a preceding ? character. For example ?exists checks if a value/object exists and ?has_content checks if a value/object is empty and exists.

Strings

Most Java String are implemented and can be used directly in Freemarker. Examples: substring, uncap_first, capitalize, date, time, datetime, ends_with, html, index_of, last_index_of, length, lower_case, upper_case, contains, replace, starts_with, trim.

Booleans

String (when used with a boolean value) converts a boolean to a string. You can use it in two ways:

• foo?string converts the boolean to string using the default strings to represent true and false values.
• foo?string("yes", "no") returns the first parameter "yes" if the boolean is true, otherwise the second parameter "no".

Dates

There are various built-ins for dates with formating capabilities. For example:

[#assign microFormatDate = content.date?string("yyyy-MM-dd") + "T" + ontent.date?string("hh:mm:ss")]

Expert

There are various expert built-ins. The most commonly used are:

has_content determines if HTML is rendered to avoid empty HTML tags.

[#if content.image?has_content]
     <img src="${contextPath + content.image}">
[/#if]

eval evaluates the passed Freemarker code.

[#assign indexString = ('"'+(ctx.indexString!)+'"')?eval]

Java objects

These rendering context objects are set in AbstractRenderer and its child classes,

content: the current content node.

${content.header!}

model: The example code below corresponds to getNavigation() method of the model class.

${model.navigation!}

def: The current page, area or component definition object.

${def.headingLevel!}

ctx: See  WebContext .

${ctx.user.name!}

<img src="${ctx.contextPath}${content.image.@path!}">

state: See  AggregationState .

${state.locale!}

Checking for null

Null checks stabilize your templates. Freemarker throws an exception if null is encountered. There are two options:

Use the ! character to provide default values. The content after ! is executed.

This code tries to assign title from content, if not it falls back to the content node's name.

<meta name="keywords" content="${content.keywords!content.title!content.@name}" />

You can also specify the value.

[#if content.keywordsEnabled!false]
     <meta name="keywords" content="${content.keywords!"These are some keywords"}" />
[/#if]

Or use the ?has_content built-in. The example renders the header in h1 tags if a value exists.

[#if content.header?has_content]
     <h1>${content.header}</h1>
[/#if]

Templating examples

Here are the most common Freemarker examples for use in your template scripts:

[#-- Accessing content --]
The value of "someProperty": ${content.someProperty}
Accessing a child node: ${content.childNode}
Accessing the child node collection: ${content?children}
Accessing the parent node: ${content?parent}
[#-- Special content properties --]
The content object is an instance of ContentMap and the following attributes are available:
The current node name: ${content.@name}
The current node path: ${content.@path}
The current node id: ${content.@id}
The current node depth: ${content.@depth}
The current node node type: ${content.@nodeType}

[#-- MetaData --]
The creation date: ${content.metaData.creationDate}
Metadata.modificationDate: ${content.metaData.modificationDate!" 
This node has never been modified."}

[#-- Component definition --]
The current component definition: ${def.name}
A component definition property: ${def.style}

[#-- Context: ctx --]
A request parmeter: ${ctx.myParam}
The current user name ${ctx.user.name} 
The current locale ${ctx.locale}

[#-- TemplatingFunctions: cmsfn--]
Create a link to a page: ${cmsfn.link(content)}
Create a binary link: ${cmsfn.link(content.image)}

[#-- Status based rendering --]
This is ${cmsfn.authorInstance?string('indeed', 'not')} an author instance.
This is ${cmsfn.editMode?string('indeed', 'not')} the edit mode.
This is ${cmsfn.previewMode?string('indeed', 'not')} the preview mode.

[#-- The Model executed before the paragraph rendering: model --]
The parent model: {model.parent}
The result of the execute method: ${actionResult}

[#-- AggregationState: state --]
Entry point of the rendering: ${state.mainContent}
Current content node: ${state.currentContent}

References

Useful links to get started with Freemarker:

• Freemarker manual.
• Freemarker quickstart guide to templating.
• Freemarker built-ins are the ?bits following expressions and providing useful functionality.
• Freemarker directives are [#blocks] of code which can be assimilated to jsp tags.