How can I update the block content programmatically?

Question

I have created a block plugin.

/src/Plugin/Block/Myblock

/**
 * Provides a 'Download component' block.
 *
 * @Block(
 *   id = "my_custom_block",
 *   admin_label = @Translation("My custom block"),
 * )
 */
class Myblock extends BlockBase {
  // Other code
}

The above block has a settings form also where I am uploading some files to the block.

I placed this block in two different regions on a page with different settings. (Uploaded different files)

Now I want to update the content of one of them i-e add a new file programmatically.

How will I do that? Because I can't load the block and update the field and save the block again because both returns me the same id my_custom_block.

$this->entityTypeManager->getStorage('block_content')->load('my_custom_block')); 

And also this returns me null.

Any idea how will I do that? Just like we update the nod entity, I want to update an instance of this block plugin.

Updated code:

I get the block like this

$node = \Drupal::routeMatch()->getParameter('node');
 if ($node instanceof \Drupal\node\NodeInterface) {
    /** @var \Drupal\layout_builder\Field\LayoutSectionItemList $layout */
    $layout = $node->get('layout_builder__layout');
    $block = $layout->getSection(0)->getComponent('1bb8e7b4-8253-40bc-a1f9-7f02e90edb2f')->getPlugin();
    $block->setConfigurationValue('file', ['6338, 6336']);
 }

Now how will I save the node using the block new configuration values?

I tried this.

 $node->get('layout_builder__layout')->getSection(0)->getComponent('1bb8e7b4-8253-40bc-a1f9-7f02e90edb2f')->setConfiguration($block->getConfiguration());
 $node->save();

Answer 1

Placed blocks are stored in the config entity block. The IDs are more or less unpredictable but you can load the blocks by specifying properties:

$entity_type_manager = \Drupal::entityTypeManager();
$blocks = $entity_type_manager->getStorage('block')->loadByProperties([
  'plugin' => 'my_custom_block',
  'region' => $region,
  'theme'  => $theme,
]);

A code example to load all blocks placed for the custom block plugin, do some checks and modify the settings:

$entity_type_manager = \Drupal::entityTypeManager();
$blocks = $entity_type_manager->getStorage('block')->loadByProperties([
  'plugin' => 'my_custom_block',
]);

foreach ($blocks as $block) {
  if ($block->getRegion() == 'my_region') {
    $settings = $block->get('settings');
    // modify settings
    $block->set('settings', $settings);
    $block->save();
  }
}