Run a cron job (or similar) in the background of WP after post update/create

I would like to run a filter on post content after it has been created or updated.

I would like this to occur after the user has submitted the post, as it may be a bit of a lengthy process (a find/replace to search for glossary terms and replace them with links).

What’s the most efficient and reliable way to achieve this?

Thanks in advance,

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Alright, here’s some code I just whipped up. Completely untested, just wrote it right off the cuff…so don’t expect it to work 100% when you drop it in, but the core concept is there, as is a decent amount of the legwork

add_action( 'my_filter_posts_content', 'my_filter_content' );
add_action( 'save_post', 'my_set_content_filter' );

if( !wp_next_scheduled( 'my_filter_posts_content' ) ) {
    wp_schedule_event( time(), 'hourly', 'my_filter_posts_content' );
}

function my_filter_content() {
    //check to see if posts need to be parsed
    if( get_option( 'my_updated_posts' ) == false )
        return false;

    //parse posts
    $ids = unserialize( get_option( 'my_updated_posts' ) );
    foreach( $ids as $v ) {
        YOUR_FUNCTION_HERE( $v );
    }

    //make sure no values have been added while loop was running
    $id_recheck = unserialize( get_option( 'my_updated_posts' ) );
    my_close_out_filter( $ids, $id_recheck );

    /*
    once all options, including any added during the running of what
    could be a long cronjob are done, remove the value and close out
    */
    delete_option( 'my_updated_posts' );
    return true;
}

function my_set_content_filter( $post_id ) {
    //get the previous value
    $ids = unserialize( get_option( 'my_updated_posts' ) );

    //add new value if necessary
    if( !in_array( $post_id, $ids ) ) {
        $ids[] = $post_id;
        update_option( 'my_updated_posts', serialize( $ids ) );
    }
}

function my_close_out_filter( $beginning_array, $end_array ) {
    $diff = array_diff( $beginning_array, $end_array );
    if( !empty ( $diff ) ) {
        foreach( $diff as $v ) {
            YOUR_FUNCTION_HERE( $v );
        }
    }
    my_close_out_filter( $end_array, unserialize( get_option( 'my_updated_posts' ) ) );
}

Method 2

Please see my answer here. It’s a proof-of-concept for running a native crontab in Linux with your WP installation.

As for WP-Cron functionality, beware of these caveats:

• WP-Cron is a pseudo cron that is runs when WP is loaded. WP checks if a WP-Cron is scheduled or behind schedule to run and then executes the cron script.
• If there is not adequate traffic, your cron might run really late.
• Scheduling a WP-Cron to run during peak hours might cause some performance issues if it’s a large, intensive script.

If you choose to go the WP-Cron route, here’s a great article to show you how to use it. You can also check out the WP functions in the Codex here.

I prefer the reliability of a Linux crontab, especially for integral, heavy-weight cron scripts. For extremely lightweight scripts, I do use WP-Cron at times.

Hope this helps!

Method 3

Would the save_post action work for you?

<?php
add_action( 'save_post', 'wp_save_post' );
function wp_save_post()
{
    // do stuff
}

You might also consider edit_post or publish_post

You can view other actions in the Codex

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0