Part of my custom form that gathers petition signatures includes some markup saying "last signer: Bob, 3 minutes ago", looked up from a database.
But if the user does not submit the form, eg they reload the page, or look elsewhere then come back to the page, the form is rendered from cache and so it still says 3 minutes ago.
What can I do?
I am not using varnish or memcached or anything else fancy that might interfere with caching. It's a very simple sure. The behaviour is seen for anonymous users. The form is used in a block, and the block is defined with DRUPAL_NO_CACHE.
The form has AJAX submission (although it must work for non-js-enabled browsers, too). I have since learnt that:
cache: ... ajax_process_form() enables form caching for all forms that include an element with the #ajax property. (The Ajax handler has no way to build the form itself, so must rely on the cached version.)
no_cache: If set to TRUE the form will NOT be cached, even if 'cache' is set.
So the question seems to point to: how can I force a form cache reset for a page load that is NOT ajax-related, e.g. in
hook_block_view()? As this would mean caching was ON (required by ajax), and can stay there for form submissions, but a page load without user input will regenerate the form?