function block_example_block_view_alter

Implements hook_block_view_alter().

This hook allows you to modify the output of any block in the system.

We are going to change the block label to uppercase if it contains the string "uppercase" or if the default block label contains this string. The default block label is set programmatically in the subject key of the block's plugin definition. The configurable block label, which can be overridden through the UI, is found in the "#configuration" key of the block's build definition. This module creates a block that demonstrates the uppercase effect in the "Example: uppercase this please" block. You can also demonstrate the effect of this hook by editing the title of an existing block or by creating a new block which where the default label has the string "uppercase" in it.

Instead of hook_block_view_alter(), which is called for all blocks, you can also use hook_block_view_BASE_BLOCK_ID_alter() to alter a specific block. To only change the "example_uppercase" block we would use the function: hook_block_view_example_uppercase_alter().

Related topics

File

modules/block_example/block_example.module, line 41

Code

function block_example_block_view_alter(array &$build, BlockPluginInterface $block) {
    // We'll search for the string 'uppercase'.
    $definition = $block->getPluginDefinition();
    if (!empty($build['#configuration']['label']) && mb_strpos($build['#configuration']['label'], 'uppercase') || !empty($definition['subject']) && mb_strpos($definition['subject'], 'uppercase')) {
        // This will uppercase the block title.
        $build['#configuration']['label'] = mb_strtoupper($build['#configuration']['label']);
    }
}