prevent same wordpress post title

Question

I am working on a wordpress site where users can submit there own posts. I would like to prevent users from adding a post with the same post_title

This is how i currently check to see if the post title exists:

$posts = $wpdb->get_col("SELECT post_name FROM $wpdb->posts WHERE post_type = 'post' AND post_status = 'publish' OR post_status = 'trash' OR post_status = 'draft'");

gets the post title from the form

$alias = $_POST['post_title'];

checks if post_title is empty if it is create a random post_title else use the user defined one

if ($_POST['post_title'] == ''){
    $alias = generateRandomString();
} else {
    $alias = $_POST['post_title'];
}

I then check to see if the post_title already exists like this:

if (in_array($alias, $items)){
    echo '<p style="color:#fff">Sorry, That Title already exists!</p>';
} else {
//insert the post
}

My issue is that wordpress will add a number after the post title if it does already exist. Is there a way to prevent wordpress from doing this?

The output of the above above shows this:

Array ( [0] => db [1] => abi [2] => ybd [3] => cc [4] => cc-2 [5] => fb )

I need to prevent the cc-2 from happening.

Answer 1

I recently ran into a similar issue (rather tackling how to reset slugs that are dirty after importing). This is a snippit of the code I used to reset the slugs:

$wpdb->update( 
    $wpdb->posts, 
    array( 'post_name' => sanitize_title( $post_to_fix->post_title ) ), 
    array( 'ID' => $post_to_fix->ID ), 
    array( '%s' ), 
    array( '%d' ) 
);

Primarily focus on sanitize_title, where it sanitizes the post title and then saves to the post_name. I believe in your case if you were to query against the post_name instead of title you would have a better chance of handling nuances in the title and providing an accurate match. So here's a rough pass at what you might look at adding into your insert post check/add logic:

// check & set from a valid $_POST property or random string for a post name
$post_name = !empty($_POST['post_title']) ? generateRandomString() : $_POST['post_title'];

// filter by post type, note it can also take an array of post types
$post_type = 'post'; 

$get_post_args = array(
    'name' => $post_name,
    'post_type' => $post_type, 
    'post_status' => 'any',
    // get all posts
    'posts_per_page' => -1,
    // improve the performance of your query
    'fields' => 'ids',
    'no_found_rows' => true,
    'update_post_term_cache' => false,
    'update_post_meta_cache' => false
    );

$dup_posts_check = new WP_Query( $get_post_args );

if( !empty($dup_posts_check) ){
    echo '<p style="color:#fff">Sorry, That Title already exists!</p>';
} else {
    //insert the post
}