How to use pre_handle_404 filter in WordPress

Example 1: Basic Usage

Here’s a simple way to use the pre_handle_404 filter. This example shows how to define a function and register it with the hook.

function weplugins_modify_pre_handle_404_defaults($preempt, $wp_query) {
    // Update the $preempt variable according to your website requirements.
    return $preempt;
}
// Add the filter
add_filter("pre_handle_404", "weplugins_modify_pre_handle_404_defaults", 10, 2);

Example 2: Removing a Hook Callback

Sometimes, you might need to remove a previously registered hook. You can use remove_filter to do this. Just make sure to provide the same callback function name, priority, and number of arguments.

remove_filter("pre_handle_404", "weplugins_modify_pre_handle_404_defaults", 10, 2);

Example 3: Conditional Modification

You can also modify the $preempt variable conditionally. This gives you more control over when the filter should or shouldn’t be applied.

function weplugins_conditional_pre_handle_404($preempt, $wp_query) {
    if ($wp_query->is_404() && !some_custom_condition()) {
        $preempt = true; // Short-circuit the 404 handling.
    }
    return $preempt;
}
// Add the filter
add_filter("pre_handle_404", "weplugins_conditional_pre_handle_404", 10, 2);

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