The Meta field control indeed works for options two and three. Thank you!

Yes, a “date range” feature would be really cool, but perhaps a bit esoteric and personally I’d already be happy with an easy way to fiddle with the query before it is run. So that I could set up a dropdown with “current quarter” / “last quarter” / etc. as selectable values and then intercept them & turn them into dates that S&F can understand before running the custom WP_query invoking the filter.

That sounds perfect! However, using that filter, I can’t seem to reach the relevant part of the query. I created a dropdown with manual values (“thisquarter”, “lastquarter”) and am seeing the selected value being passed to the search page: (my url)?_sfm_period=thisquarter

However, when I try to get hold of _sfm_period using the filter you mentioned, it isn’t there! What I see is

Array
(
[paged] => 1
[search_filter_id] => 3136
[search_filter_override] =>
[posts_per_page] => 500
[meta_query] => Array
(
)

[post_type] => shops

Which appear to be the static parts of the form but not the properly spelled out query (yet).

Should I just add my correct date values to the meta_query array?

OK! The custom filter route didn’t work out – looking at the plugin source code I don’t think anything is ever actually done with search_filter_override. I tried looking at global $searchandfilter but that doesn’t seem really open to outside manipulation. But, I can intercept the $_GET parameters directly and do my changes there. It’s hacky, but it does the job.

Sadly I still can’t do what I need to do, though, because the workflow I’m creating has the search bar as a permanent feature on the page and the period selector will always snap back to the default value while everything else stays in place. That’s not acceptable from a UX perspective. Say for example, I have a form with

– A dropdown linked to an unused “period” meta field, with the values ‘last_month’, ‘last_quarter’
– A date_from and date_to field

Now after submitting the form, I can fiddle with $_GET, parse the period parameter and set date_from and date_to accordingly. But I have to remove $_GET["sfm_period"] because otherwise that gets used as a filter, which would of course yield 0 results! I can remove the field but then S&F will think the value is not set, and the “period” dropdown will snap back to its default value.

What this would require is the ability to have dropdowns that aren’t actually linked to a real meta field and so what you select there doesn’t play into the query.

Any ideas around this would be welcome.

Fair enough!

Should anyone else have the same problem: I’ve managed to find a hacky but reasonable solution for now: when parsing the drop-down contents (like turning “last_quarter” into a start and an end date) I inject some JavaScript into the document that sets the dropdown to the right value.

if (isset($_GET["_sfm_pseudofield_daterange"])) {
   
    $daterange = $_GET["_sfm_pseudofield_daterange"];
    ....  Handle the date stuff

    // Now remove the GET parameter so it doesn't get used as a filter and lead to 0 results
    unset($_GET["_sfm_pseudofield_daterange"]);

    // Use JavaScript to correctly set the dropdown again even though GET parameter was unset
    add_action( 'wp_head', function() use($daterange) {
       ?><script>jQuery(document).ready(function(){ jQuery("[name='_sfm_pseudofield_daterange[]']").val("<?= htmlentities($daterange);?>");});</script><?
		} );
}

As a feature request, it would be awesome to have a new “empty” field type (Text field, dropdown, check box, etc.) that gets passed along with the rest of the form, plus a documented interface for altering query parameters in the sf_edit_query_args hook.