How to create URL parameters to run custom queries?

Question

I'd like to filter by Custom Fields, my goal is to have links with url parameters like:

domain.com/?custom_field=white

I think i can create the custom query by tweaking this examples: https://www.advancedcustomfields.com/resources/query-posts-custom-fields/

But how can i put all together in a site plugin or functions.php so when someone clicks my URL parameter it actually runs my query? I can't seem to find the answer to that step.

Answer 1

What you want to do is access the query_vars and use them.

Base code:

Page to access the fields

$custom_field = get_query_var('custom_field');
var_dump($custom_field);

And the function or custom plugin to save the magic:

add_filter( 'query_vars', 'my_custom_query_vars' );
function my_custom_query_vars( $vars ) {
    $vars[] = 'custom_field';
    $vars[] = 'custom_awesome_field';

    return $vars;
}

yourawesomesite.awesome/?custom_field=white

string 'white' (length=5)