"Page cache maximum age" is set to "no caching" but the block seems to be cached

Question

I have a Drupal 8 standard installation on Azure. I wrote a block that uses PHP to load external content; I added a timestamp to the block as well. Under Page cache maximum age, the site is set to no caching. When I refresh the page, the timestamp doesn't update telling me it's not attempting to reload. If I manually clear the cache, all is good and the timestamp updates.

Why would this be?

As I mentioned before, these blocks are loading external content. Ideally I could set it so that these blocks alone wouldn't be cached. Is this possible?

Answer 1

To disable caching of the block add this to the php code:

  $build['#cache']['max-age'] = 0;
  \Drupal::service('page_cache_kill_switch')->trigger();

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