模板脚本

脚本语言和绘制器

Magnolia CMS为FreeMarker和JSP提供可立即使用的绘制器。您可以选择偏好的语言，甚至可以在相同的网站上混合使用，在一些模板里使用FreeMarker而另一些里用JSP。 

FreeMarker

在Magnolia里，我们更倾向于使用FreeMarker，因其灵活性，较清晰的语法，更好的错误报告机制，也因为它不依赖于文件系统。模板不需要导出到文件系统，这意味着您可以将它们存储在内容库中，并像其他资源一样获得，随意添加版本控制，以及添加定制的属性和元数据。

样例：绘制页面标题，如果没有标题则绘制名字。

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

这是FreeMarker提供的一些好处：

• 它是一种通用的模板语言，不束缚于Java环境。
• 提供基本的指令，如[if]，[else]和[list]。
• 有一大套built-ins。
• 可以调用任何Java对象和返回对象的公共方法。
• 不需要在请求／回复环境中绘制。
• 提供直接获取节点对象（beans）的方法。
• 可直接迭代任何扩展一个Java列表的内容集合。
• 严格的null值处理导致稳定的模板。
• 需要的话允许使用JSP标签库。

JSP

JSP代表JavaServer Pages，是Java Servlet技术的一个延伸，用于综合Java服务器端的程序和HTML。

样例：绘制页面标题，如果没有标题则绘制名字。

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

其他语言

您也可以使用另一模板语言。例如，有一些网站使用Apache Velocity。如果有您使用的语言可用的绘制器，很有可能可以将它合入Magnolia CMS。这就能够让您使用您熟悉的模板语言了。

绘制器配置

FreemarkerRenderer和JspRenderer在Configuration应用的/modules/rendering/renderers/freemarker和/jsp里配置。

STK定义它自己的绘制器STKRenderer，在Configuration应用 > /modules/standard-templating kit/rendering/renderers/stk里配置。

页面, 区域和组件定义里的renderType属性定义使用的模板绘制器。对STK模板来说，类型是stk。

加载脚本

系统可以从三个地方加载FreeMarker脚本，以下列顺序：

1. 网络应用程序的文件系统。您可以将脚本文件放在/<CATALINA_HOME>/webapps/<contextPath>/templates文件夹。
2. templates 工作区。模板需被使能才能被考虑进去。
3. 网络应用程序的类路径（classpath）。这是STK模板默认存放的地方。最佳实践是在模块JAR里打包脚本。模块JAR在类路径里好让系统找得到它。

模板加载器

FreeMarker模板加载器在Configuration应用的/server/rendering/freemarker/jcr和/webapp里配置：

• LazyWebappTemplateLoader默认从webapp文件夹里加载模板。如果没找到匹配的模板，则将会从类路径中加载。
• JcrRepoTemplateLoader允许从内容库中加载模板。加载器包含在In-place Templating模块。
• LazyFileTemplateLoader允许从文件系统的专有位置中加载模板。

需要的话您也可以写下您自己定制的模板加载器。

开发时，在内容库里编辑脚本有时候很有用。这种方法只对FreeMarker脚本有效。如果您将脚本导入templates工作区，它们就会在STK > Templates里可见可用。所有的STK脚本都遵循这个模式。您可以从以上的加载顺序看出，在templates工作区里的脚本会覆写从类路径里加载的脚本。一旦被添加或修改，则需要选中Enable template复选框来强迫Magnolia CMS从内容库中加载模板。

STK脚本

STK模板脚本在网络应用程序的类路径中。其副本在STK > Templates里就可以编辑。STK脚本是用FreeMarker写的。

脚本存储在/templating-kit文件夹的子文件夹里：

• components包含按照组件类型分类的组件模板。
• pages包含main页面脚本，区域脚本在子文件夹里。

此结构遵循模板原型结构。在模板原型里引用的区域模板都被存在/global文件夹里。

main脚本

main是主页面脚本（Git）。它是理解这个系统的一个好起点。它在编写实例上使用@cms.init指令初始化页面编辑器，也包含了设置bodyClass和bodyID的逻辑。

main脚本使用@cms.area指令来调用区域绘制它们自身。它使用#include指令绘制导航。main脚本用三个DIV元件包装区域，建立了一个可调的页面网格。

区域脚本

参考STK区域里关于STK区域脚本的描述。

指令

关键的模板特性以指令（directives）形式在Magnolia CMS标签库里可用。指令输入很快，但会绘制复杂的输出。

标准FreeMarker指令

这里有一些最有用的FreeMarker指令及其样例代码：

if, else和elseif

支持常用运算符（&&, ||, !, ==, !=, >, <, >=, <=）。

布尔测试：

[#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

可在任何扩展Java集的集合里进行迭代。Can iterate over any collection that extends a Java collection.

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

assign

assign允许您定义变量。任何非空对象都能被传递给变量。

[#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

include指令包含一个FreeMarker模板脚本。

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

macros

Macros使您复用FreeMarker代码片段。参考Templating Kit > Templates /templating-kit/components/macros里STK使用的例子。

[#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"/]

定制Magnolia指令

Magnolia CMS provides the following custom directives:

• cms:init: embeds JavaScript and CSS needed to author pages.
• 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 the Configuration app > 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 InitElement Java 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. Editors can 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 and an end marker. The value of the title property in the area definition is rendered on the bar. When an editor clicks the Add icon in the New Component box 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 map.

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 embeds the necessary CSS and JavaScript on the author instance.
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. Go to the Configuration app > /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]

DamTemplatingFunctions provides direct access to Assets and defines useful methods. The methods are exposed as damfn. See DAM templating for more information. For example:

[#assign asset = damfn.getAssetForId(content.link)][#assign assetMap = damfn.getAssetMapForAssetId(content.link)]

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 the abbreviateString example.

[#assign text = stkfn.abbreviateString(text, 80)]

The templating functions classes are configured for each renderer in the Configuration app > /<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.author?has_content]
 <p>
  <cite>${content.author}</cite>
 </p>
[/#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!}

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.