How to use comment_feed_join filter in WordPress

comment_feed_join filter

Filters the JOIN clause of the comments feed query before sending.

To use comment_feed_join 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 weplugins_modify_comment_feed_join_defaults which takes 2 parameters and we registered using add_filter. The first parameter comment_feed_join is name of the hook, The second parameter weplugins_modify_comment_feed_join_defaults is name of the function which need to be called, third parameter is the priority of calling the hook if same hook is used multiple times and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometime, you have to remove a registered hook so you can use remove_filter to remove comment_feed_join filter.

Parameters

Below are the 2 parameters required to use this hook:

• $cjoin : (string) The JOIN clause of the query.
• $query : (WP_Query) The WP_Query instance (passed by reference).

Live Example

apply_filters_ref_array( 'comment_feed_join', string $cjoin, WP_Query $query )

Below is an example how you can use this hook.

Example 1: Basic Usage

This example demonstrates how to modify the JOIN clause of the comments feed query.

    function weplugins_modify_comment_feed_join_defaults($cjoin, $query) {
        // Update the $cjoin variable according to your website requirements and return this variable. You can modify $cjoin conditionally too if you want.
        return $cjoin;
    }
    // add the filter
    add_filter("comment_feed_join", "weplugins_modify_comment_feed_join_defaults", 10, 2);
    

Example 2: Conditional JOIN Modification

This example shows how to conditionally modify the JOIN clause based on specific query conditions.

    function weplugins_modify_comment_feed_join_conditional($cjoin, $query) {
        if ($query->is_main_query() && $query->is_feed) {
            // Modify $cjoin based on conditions
            $cjoin .= ' LEFT JOIN wp_custom_table ON wp_comments.comment_ID = wp_custom_table.comment_ID';
        }
        return $cjoin;
    }
    // add the filter
    add_filter("comment_feed_join", "weplugins_modify_comment_feed_join_conditional", 10, 2);
    

Example 3: Removing the Hook

To remove a hook callback, you can use the example below.

    // remove the filter
    remove_filter("comment_feed_join", "weplugins_modify_comment_feed_join_defaults", 10, 2);
    

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

Contact Us

If you need customization or are facing any issues with this hook, feel free to contact us.