Modifying Entity Render Arrays in Drupal 11 with Pre-Render Callbacks

Staff Reporter

Drupal 11: How To Alter Entity View Builder Configuration Before Rendering

Phil Norton has outlined a Drupal 11 technique for injecting custom attributes into entity render arrays using the #pre_render property. The method was developed in response to a challenge rendering a media entity in a block where additional markup attributes were needed. Instead of relying on preprocess hooks, which lose execution context, Norton embedded a pre-render callback directly into the render array, enabling attribute injection at the final rendering stage.

The approach involves setting up a render array using the entity_type.manager service and attaching a static method as a callback via #pre_render. To ensure this method is trusted and secure, the class implements TrustedCallbackInterface and registers the method name in trustedCallbacks(). In the example provided, the callback method dynamically injects height and width attributes into a media image, giving developers precise control over the output without needing to create new view modes or modify theme templates. Norton also demonstrates how to extract image dimensions from the source file using the image.factory service, allowing the attributes to reflect the actual properties of the image or be adjusted proportionally.

While Drupal offers #post_render callbacks as well, Norton advises caution as these operate on fully rendered markup and typically require fragile string manipulation. His solution, which keeps all logic within the render array lifecycle, provides a cleaner, more contextual way to modify entity output. This pattern is especially useful in block plugins and embedded components, where isolated, programmatic control over rendering is preferred.

Reference: Drupal 11: How To Alter Entity View Builder Configuration Before Rendering by Philip Norton, #! code (Hash Bang Code) (7 December 2025)

Drupal 11

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