Introduction to Fluid

Fluid is TYPO3’s default rendering engine but can also be used in standalone PHP projects. The Fluid source code is being developed as an independent project outside of the TYPO3 Core.

Fluid is based on XML and you can use HTML markup in Fluid.

Fluid ViewHelpers can be used for various purposes. Some transform data, some include Partials, some loop over data or even set variables. You can find a complete list of them in the ViewHelper Reference.

You can write your own custom ViewHelper, which is a PHP component.

Example Fluid snippet

This is how a simple Fluid snippet could look like:

EXT:site_package/Resources/Private/Templates/SomeTemplate.html
<h4>This is your headline</h4>
<p>
 <f:if condition="{myExpression}">
   <f:then>
      {somevariable}
   </f:then>
   <f:else>
       {someothervariable}
   </f:else>
 </f:if>
</p>

The resulting HTML may look like this:

Example frontend output
<h4>This is your headline</h4>
<p>This is the content of variable "somevariable"</p>

The above Fluid snippet contains:

ViewHelpers:

The XML elements that start with f: like <f:if> etc. are standard ViewHelpers. It is also possible to define custom ViewHelpers, for example <foo:bar foo="bar">. A corresponding file ViewHelpers/BarViewHelper.php with the methods initializeArguments and render contains the HTML generation logic. ViewHelpers are Fluid components which make a function call to PHP from inside of a template. TYPO3 adds some more ViewHelpers for TYPO3 specific functionality.

ViewHelpers can do simple processing such as remove spaces with the spaceless ViewHelper or create a link as is done in the TYPO3 Fluid Viewhelper link.page.

Expressions, variables:

Fluid uses placeholders to fill content in specified areas in the template where the result is rendered when the template is evaluated. Content within braces (for example {somevariable}) can contain variables or expressions.

Conditions:

The conditions are supplied here by the if / then / else ViewHelpers.

Directory structure

In your extension, the following directory structure should be used for Fluid files:

── Resources
   └── Private
     ├── Layouts
     ├── Partials
     └── Templates

This directory structure is the convention used by TYPO3 CMS. When using Fluid outside of TYPO3 CMS you can use any folder structure you like.

If you are using Extbase controller actions in combination with Fluid, Extbase defines how files and directories should be named within these directories. Extbase uses sub directories located within the "Templates" directory to group templates by controller name and the filename of templates to correspond to a certain action on that controller.

└── Resources
    └── Private
        └── Templates
            └── Blog
                ├── List.html (for Blog->list() action)
                └── Show.html (for Blog->show() action)

If you don't use Extbase you can still use this convention, but it is not a requirement to use this structure to group templates into logical groups, such as "Page" and "Content" to group different types of templates.

In Fluid, the location of these paths is defined with \TYPO3Fluid\Fluid\Core\Rendering\RenderingContext->setTemplatePaths().

TYPO3 provides the possibility to set the paths using TypoScript.

Templates

The template contains the main Fluid template.

Layouts

optional

Layouts serve as a wrapper for a web page or a specific block of content. If using Fluid for a sitepackage, a single layout file will often contain multiple components such as your sites menu, footer, and any other items that are reused throughout your website.

Templates can be used with or without a Layout.

  • With a Layout anything that's not inside a section is ignored. When a Layout is used, the Layout determines which sections will be rendered from the template through the use of <f:render> in the Layout file.

  • Without a Layout anything that's not inside a section is rendered. You can still use sections of course, but you then must use f:render in the template file itself, outside of a section, to render a section.

For example, the layout may like this

EXT:my_extension/Resources/Private/Layouts/Default.html
<div class="header">
   <f:render section="Header" />
</div>
<div class="main">
   <f:render section="Main" />
</div>

The layout defines which sections are rendered and in which order. It can contain additional arbitrary Fluid / HTML. How you name the sections and which sections you use is up to you.

The template should include the sections which are to be rendered.

EXT:my_extension/Resources/Private/Layouts/Default.html
<f:layout name="Default" />

<f:section name="Header">
   <!-- add header here ! -->
</f:section>

<f:section name="Main">
   <!-- add main content here ! -->
</f:section>

Partials

optional

Some parts within different templates might be the same. To not repeat this part in multiple templates, Fluid offers so-called partials. Partials are small pieces of Fluid template within a separate file that can be included in multiple templates.

Partials are stored, by convention, within Resources/Private/Partials/.

Example partial:

EXT:my_extension/Resources/Private/Partials/Tags.html
<b>Tags</b>:
<ul>
   <f:for each="{tags}" as="tag">
      <li>{tag}</li>
   </f:for>
</ul>

Example template using the partial:

EXT:my_extension/Resources/Private/Templates/Show.html
<f:render partial="Tags" arguments="{tags: post.tags}" />

The variable post.tags is passed to the partial as variable tags.

If ViewHelpers from a different namespace are used in the partial, the namespace import can be done in the template or the partial.

Example: Using Fluid to create a theme

This example was taken from the example extension for TYPO3 Sitepackage Tutorial and reduced to a very basic example.

The Sitepackage Tutorial walks you through the creation of a sitepackage (theme) using Fluid. In our simplified example, the overall structure of a page is defined by a layout "Default". We show an example of a three column layout. Further templates can be added later, using the same layout.

Resources/
└── Private
    ├── Layouts
    │   └── Page
    │       └── Default.html
    ├── Partials
    │   └── Page
    │       └── Jumbotron.html
    └── Templates
        └── Page
            └── ThreeColumn.html

Set the Fluid paths with TypoScript using FLUIDTEMPLATE

lib.dynamicContent = COA
lib.dynamicContent {
   10 = LOAD_REGISTER
   10.colPos.cObject = TEXT
   10.colPos.cObject {
      field = colPos
      ifEmpty.cObject = TEXT
      ifEmpty.cObject {
         value.current = 1
         ifEmpty = 0
      }
   }
   20 = CONTENT
   20 {
      table = tt_content
      select {
         orderBy = sorting
         where = colPos={register:colPos}
         where.insertData = 1
      }
   }
   90 = RESTORE_REGISTER
}

page = PAGE
page {
   // Part 1: Fluid template section
   10 = FLUIDTEMPLATE
   10 {
      templateName = Default
      templateRootPaths {
         0 = EXT:site_package/Resources/Private/Templates/Page/
      }
      partialRootPaths {
         0 = EXT:site_package/Resources/Private/Partials/Page/
      }
      layoutRootPaths {
         0 = EXT:site_package/Resources/Private/Layouts/Page/
      }
   }
}
Resources/Private/Layouts/Page/Default.html
<f:render section="Header" />
<f:render section="Main" />
<f:render section="Footer" />
Resources/Private/Templates/Page/ThreeColumn.html
 1<f:layout name="Default" />
 2
 3<f:section name="Header">
 4   <!-- add header here ! -->
 5</f:section>
 6
 7<f:section name="Main">
 8   <f:render partial="Jumbotron" />
 9    <div class="container">
10      <div class="row">
11        <div class="col-md-4">
12          <f:cObject typoscriptObjectPath="lib.dynamicContent" data="{colPos: '1'}" />
13        </div>
14        <div class="col-md-4">
15          <f:cObject typoscriptObjectPath="lib.dynamicContent" data="{colPos: '0'}" />
16        </div>
17        <div class="col-md-4">
18          <f:cObject typoscriptObjectPath="lib.dynamicContent" data="{colPos: '2'}" />
19        </div>
20      </div>
21    </div>
22</f:section>
23
24<f:section name="Footer">
25    <!-- add footer here ! -->
26</f:section>
  • The template uses the layout "Default". It must then define all sections that the layout requires: "Header", "Main" and "Footer".

  • In the section "Main", a partial "Jumbotron" is used.

  • The template makes use of column positions (colPos). The content elements for each section on the page will be rendered into the correct div. Find out more about this in Backend layout.

  • Again, we are using Object Accessors to access data (e.g. {colPos: '2'}) that has been generated elsewhere.

Resources/Private/Partials/Page/Jumbotron.html
<div class="jumbotron">
   <div class="container">
      <h1 class="display-3">Hello, world!</h1>
      <p> some text </p>
   </div>
</div>