Using Different Output Formats

The Model-View-Controller-Paradigm (MVC), as described in chapter 2, has many decisive advantages: It separates the model from the user interaction and it allows different output formats for the same data. We want to discuss the later.

Often different output formats are useful when generating content for CSV files, RSS feeds or print views. On the example of the blog we will show you, how you can extend your Extension with a print view.

Lets assume you have programed a HTML view for a list of blog posts. The Fluid template of this view is Resources/Private/Templates/Post/list.html. Now you want to add a print view, which is formatted differently. Create a new template Resources/Private/Templates/Post/list.print and write the appropriate Fluid markup to generate the print view. You can use the format attribute of the link ViewHelper to generate a link to the print view:

<f:link.action action="list" format="print">Print View</f:link.action>

The same list action is being called that was used for the HTML view. However, Fluid doesn’t choose the file list.html but list.print, because the format attribute of the link.action ViewHelper changed the format to print, our print view. You notice: The format is being reflected in the file ending of the template.

Tip

In the example above we have given the print view the name print. All format names are treated equally. There are no technical limitations for format names. Therefore you should choose a semantically, meaningful name.

Output other formats with Fluid

If you want to output JSON, RSS or similar data with Fluid, you have to write the appropriate TypoScript which passes the page rendering to Extbase and Fluid respectively. Otherwise, TYPO3 will always generate the <head>- and <body>-section.

You can use the following TypoScript:

rss = PAGE
rss {
   typeNum = 100
   10 =< tt_content.list.20.*[ExtensionKey]*_*[PluginName]*

   config {
      disableAllHeaderCode = 1
      additionalHeaders = Content-type:application/xml
      xhtml_cleaning = 0
      admPanel = 0
   }
}

You still have to exchange [ExtensionKey] and [PluginName] with the name of the Extension and Plugin. We recommend to search for the path of your Plugin in the TypoScript Object Browser to avoid misspelling. Further on you have to explicitly set plugin.tx_*[ExtensionKey]*.persistence.storagePid to the number of the page containing the data to tell Extbase from which page the data should be read.

Using built in JsonView

Extbase provides the \TYPO3\CMS\Extbase\Mvc\View\JsonView as an alternative to \TYPO3\CMS\Fluid\View\TemplateView which is used by default.

The intention is to provide the same public API, e.g. assign variables to the view, but replace the rendering. The View itself needs further configuration about how to convert assigned variables to JSON format.

Switching php class of view

In order to use this view, these are multiple possible ways within controller:

  1. Replace default view by changing property $defaultViewObjectName:

    protected $defaultViewObjectName = \TYPO3\CMS\Extbase\Mvc\View\JsonView::class;

  2. Switch property values within an initialize*Action() method:

    public function initializeSpecialAction()
{
    $this->defaultViewObjectName = \TYPO3\CMS\Extbase\Mvc\View\JsonView::class;
}

Configuring JsonView

Once the view is in use, it needs to be configured:

$this->view->setConfiguration([
    'customVariable' => [
        '_only' => [
            'key1',
            'key3',
        ],
    ],
]);

$this->view->setVariablesToRender(['customVariable']);

$this->view->assignMultiple([
    'anotherVariable' => 'value',
    'customVariable' => [
        'key1' => 'value1',
        'key2' => 'value2',
        'key3' => [
            'key3.1' => 'value3.1',
            'key3.2' => 'value3.2',
        ],
    ],
]);

The above example will result in the following output:

{
    "key1": "value1",
    "key3": {
        "key3.1": "value3.1",
        "key3.2": "value3.2"
    }
}

The following is happening during rendering:

  1. Only allowed variables are rendered. In above example only customVariable is allowed due to setVariablesToRender(['customVariable']) call. Therefore variable anotherVariable is ignored during rendering.
  2. Only allowed properties of variables are rendered. In above example only key1 and key3 are allowed, due to setConfiguration() call. Therefore key2 is ignored.

Further examples

Example 1 for setConfiguration() call:

$this->view->setConfiguration([
   'variable1' => [
      '_only' => [
         'property1',
         'property2',
         // ...
      ],
   ],
   'variable2' => [
      '_exclude' => [
         'property3',
         'property4',
         //...
      ],
   ],
   'variable3' => [
      '_exclude' => ['secretTitle'],
      '_descend' => [
         'customer' => [
            '_only' => ['firstName', 'lastName'],
         ],
      ],
   ],
   'somearrayvalue' => [
      '_descendAll' => [
         '_only' => ['property1'],
      ],
   ],
]);

Of variable1 only property1 and property2 will be included. Of variable2 all properties except property3 and property4 are used. Of variable3 all properties except secretTitle are included.

If a property value is an array or object, it is not included by default. If, however, such a property is listed in a “_descend” section, the renderer will descend into this sub structure and include all its properties (of the next level).

The configuration of each property in “_descend” has the same syntax like at the top level. Therefore - theoretically - infinitely nested structures can be configured.

To export indexed arrays the _descendAll section can be used to include all array keys for the output. The configuration inside a _descendAll will be applied to each array element.

Example 2 for setConfiguration() call: exposing object identifier:

$this->view->setConfiguration([
   'variableFoo' => [
      '_exclude' => ['secretTitle'],
      '_descend' => [
         'customer' => [    // consider 'customer' being a persisted entity
            '_only' => ['firstName'],
            '_exposeObjectIdentifier' => TRUE,
            '_exposedObjectIdentifierKey' => 'guid',
         ],
      ],
   ],
]);

Note for entity objects you are able to expose the object’s identifier also, just add an “_exposeObjectIdentifier” directive set to TRUE and an additional property __identity will appear keeping the persistence identifier. Renaming that property name instead of ‘__identity’ is also possible with the directive _exposedObjectIdentifierKey. Example 2 above would output (summarized): {"customer":{"firstName":"John","guid":"892693e4-b570-46fe-af71-1ad32918fb64"}}

Example 3 for setConfiguration() call: exposing object’s class name:

$this->view->setConfiguration([
   'variableFoo' => [
      '_exclude' => ['secretTitle'],
      '_descend' => [
         'customer' => [    // consider 'customer' being an object
            '_only' => ['firstName'],
            '_exposeClassName' => TYPO3\CMS\Extbase\Mvc\View\JsonView::EXPOSE_CLASSNAME_FULLY_QUALIFIED,
         ],
      ],
   ],
]);

The _exposeClassName is similar to the objectIdentifier one, but the class name is added to the JSON object output, for example (summarized): {"customer":{"firstName":"John","__class":"Acme\Foo\Domain\Model\Customer"}}

The other option is EXPOSE_CLASSNAME_UNQUALIFIED which only will give the last part of the class without the namespace, for example (summarized): {"customer":{"firstName":"John","__class":"Customer"}} This might be of interest to not provide information about the package or domain structure behind.