Processed Resources app

The Processed Resources App enables processing of resource files. When a resource (CSS or JavaScript) is "processed" its content is interpreted as a FreeMarker template. You can use FreeMarker constants, variables and expressions inside the resource text. Magnolia evaluates them before serving the resources to the client.

New Web technologies such as Syntactically Awesome Style Sheets ( Sass ) and  Less have largely replaced the need to do FreeMarker pre-processing for CSS files. You can now accomplish the same with a dedicated CSS pre-processor. We recommend that you start using such new technologies. Magnolia provides the  /resources path (without dot) as a legacy option to support older projects.

Configuration

The Processed Resources app is configured in /modules/processed-resources-app.

What is a processed resources?

When a resource (CSS or JavaScript) is "processed" its content is interpreted as a FreeMarker template. You can use FreeMarker constants, variables and expressions inside the resource text. Magnolia evaluates them before serving the resources to the client.

Using the app

Go to Web Dev > Processed Resources to open the app.

Processed resource templates

You can process different types of files. Choose a template that matches the file type:

• Processed CSS, HTML and JS: These templates interpret the resource as a Freemarker template before serving it to the client. Use the templates to post-process CSS, HTML or JavaScript. You can use any FreeMarker constants, variables and expressions in the file text. You can also access Magnolia content and configuration using cmsfn templating functions.
  
• Non-processed CSS, HTML, JS and YAML: These templates do not process the resource. The resource is treated as a static file and served to the client as such. However, you get an editor that provides syntax highlighting and search for the designated file type.
   
• Reference: Create a reference to another resource in the same workspace. This is useful for providing aliases.
• Binary: Use this template for non-editorial binary resources that change rarely such as logos, icons and fonts.

Loading processed resources with /resources path

Use the  /resources path (without dot) to load processed resources.

Example: Referencing a processed CSS file

<link rel="stylesheet" href="${ctx.contextPath}/resources/my-module/css/all-styles.css">

The /resources path is mapped to the resources workspace in /server/URI2RepositoryMapping/mappings/resources using URI to repository mapping. This ensures that resources are loaded correctly also in projects that are built on earlier versions of Magnolia which you may want to run on Magnolia 5.4.

 When you reference a resource with the /resources path, the resource is not loaded by  ResourcesServlet  and the three origins are not checked.

Use cases

Using variables in CSS

When building large sites, authors often face a maintainability challenge. In such websites, the size of the CSS is quite large and a lot of information may be repeated in multiple places. For example, maintaining a coherent color scheme throughout a document implies reusing a few color values at numerous positions in the CSS files. Altering the scheme, whether tweaking a single color or completely rewriting it, therefore becomes a complex task requiring precision, as a single find and replace often isn't enough. – Mozilla Developer Network: Using CSS variables

You can create equivalent functionality that is equivalent to CSS variables with processed resources in Magnolia.

Example: This Processed CSS resource defines a Freemarker variable textColor and assigns it a value. We reference the variable later in the same file.

[#assign textColor="#ff0099"]
p {
    font-family: Verdana, sans-serif;
    font-size: 11px;
    color: ${textColor};
}

When the resource is processed, the Freemarker expressions are evaluated and the resulting CSS is served to the client.

p {
    font-family: Verdana, sans-serif;
    font-size: 11px;
    color: #ff0099;
}

Merging JavaScript files

Merging several JavaScript files into one file makes sense if you load the same JavaScript everywhere. Consider creating packages of JavaScript files that always go together:

• Third-party libraries: jQuery, jQuery UI and jQuery plugins
• General application code: form handling, logging in/out and navigation
• Page-specific code: carousel, news, commenting

Example: Merging jQuery plugins

The parent resource is Processed JavaScript template. The child nodes are normal non-processed JavaScript templates.

In the parent resource, use a FreeMarker list directive to iterate through the children and access their content:

[#list cmsfn.children(content) as child ]
    [@cms.component content=child /]
[/#list]

When you request the parent resource you get one long file with all the child scripts appended.

 Processing is not recursive. This means, FreeMarker expressions are only evaluated in the parent node, not in child nodes.

Aliasing

Third-party JavaScript libraries get versioned frequently. You may want the latest version of a library in your project but don't want to keep updating references in all template scripts every time the resource file name changes. Or you may want minified and pretty-print versions of the same JavaScript with friendly file names.

Example: Create a resource file  jquery-1.12.0.min.js  using the JavaScript template. This is the complex file name that has a version number. Create a friendly resource jquery-min.js using the Reference template. Reference the first from the second.

Now you can reference jQuery from template scripts with a stable, friendly resource name:

<script src="${ctx.contextPath}/resources/jquery-min.js"></script>

When the library is updated you only need to update the reference, no need to touch the templates.

Using a model class

You can implement a custom model class and access the model's methods from inside a CSS or JavaScript document. In the model class you can use any Java logic or Magnolia functionality.

Enter the fully-qualified class name of the model class in the Model Class box in the resource properties dialog.