How to use query_string filter in WordPress

query_string filter

Filters the query string before parsing.

To use the query_string filter, first you have to register it using add_filter. You can write this code into functions.php of your activated theme or in a custom WordPress Plugin.

We at WePlugins always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function modify_query_string_defaults which takes 1 parameter and we registered using add_filter. The first parameter query_string is the name of the hook, the second parameter modify_query_string_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook so you can use remove_filter to remove the query_string filter.

Parameters

Below the 1 parameter is required to use this hook.

• $query_string : (string) The query string to modify.

Live Examples

Example 1: Basic Query String Modification

Below is an example of how you can use this hook to modify the query string.

    function weplugins_modify_query_string_defaults($query_string) {
        // Update the $query_string variable according to your website requirements and return this variable.
        return $query_string;
    }
    // add the filter
    add_filter("query_string", "weplugins_modify_query_string_defaults", 10, 1);
    

Example 2: Conditional Query String Modification

This example shows how to conditionally modify the query string based on specific criteria.

    function weplugins_conditional_modify_query_string($query_string) {
        if (is_home()) {
            $query_string .= '&home=true';
        }
        return $query_string;
    }
    // add the filter
    add_filter("query_string", "weplugins_conditional_modify_query_string", 10, 1);
    

Example 3: Removing the Hook

To remove a hook callback, use the example below.

    // remove the filter
    remove_filter("query_string", "weplugins_modify_query_string_defaults", 10, 1);
    

Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.

Contact Us

If you’re having any trouble using this hook or need customization, please Contact Us and we’d be happy to assist you.