Wordpress hook before inserting post into database

Question

I need to do check the inserted post for certain keywords and perform some functions depending on the keywords found.

is there a wordpress hook that executes "just before the post is inserted into the database" ? Or will i have to modify wordpress core ?

Also, i will need to prevent the post from being inserted into the database if some keywords are found. is this something that can be done with a hook ? Or will a core modification be needed ?

Answer 1

Available actions:

1. pre_post_update - Runs just before a post or page is updated.
2. publish_post - Runs when a post is published, or if it is edited and its status is "published".
3. save_post - Runs whenever a post or page is created or updated, which could be from an import, post/page edit form, xmlrpc, or post by email.
4. wp_insert_post - Same as save_post, runs immediately afterwards.

More info: Plugin API/Action Reference

Usage:

<?php
add_action('action_name', 'callback_name');

Answer 2

The hook is save_post:

add_action('save_post', 'dosomething'), 10, 2);

Answer 3

the hook is wp_insert_post_data

which as two parameters ($data, $postarr) and its a filter hook that fires before inserting the post into the database so:

add_filter('wp_insert_post_data','callback_function');

as for save_post hook it happens after inserting the post to database.

Answer 4

Wordpress likes to do auto-saves / auto-drafts. There is no hook currently available to stop an insert based on specific post data.

However, you can stop the post from being published based on specific post data by using wp_die(). I have used this to check for duplicate SKUs on ecommerce sites.

In this example I am getting the "SKU" value from an ACF Field, but if you're not using ACF that's fine, just use print_r($_POST); to view your post data, and go from there.

This example also checks to see if the post we are updating is a custom post type, you could also omit that if not required.

//Check if a SKU already exists, and display an error if it does
add_action('pre_post_update', 'tix_check_for_duplicate_sku', 1, 2);
function tix_check_for_duplicate_sku( $post_id, $data ) {

    //Check if we are updating a product (custom post type) if not, just return
    if (get_post_type() != 'tix_product') return;

    $sku = $_POST['acf']['field_662e98fccf0da']; 

    if ($sku != "") {

        $sku_check = new WP_Query([
            'post_type' => 'tix_product',
            'post_status' => 'publish',
            'posts_per_page' => 1,
            'post__not_in' => array($post_id),
            'meta_key' => 'sku',
            'meta_value' => $sku,
            'fields' => 'ids'
        ]);

        if ($sku_check->found_posts >= 1) {

            wp_die('Duplicate SKU: '.$sku.' exists.  All SKUs must be unique! Please go back and change it...', 'Duplicate SKU', array('back_link' => true));

        }

    } 

}