How to prevent duplicate posts with wp_insert_post in Wordpress

To save the link in the post meta you can use update_post_meta
like this for example:

 

$url = "http://sample.com/entertainment/

default.aspx?tabid=2305&conid=102950";

 
$my_post = array(
'post_title' => "$title",
'post_content' => "$content",
'post_status' => 'draft',
'post_author' => 1,
'post_category' => array(1),
);
$post_id =  wp_insert_post( $my_post );
update_post_meta($post_id,'source_link',$url);

and to prevent the insertion add a simple conditional check:

$args = array("meta_key" => "source_link", "meta_value" =>$url);
$posts = get_posts($args);
if (count($posts) < 0){
//add new post
}

---

if (count($posts) < 0){

}

is not working, change it to

**if (empty($posts))**{ 

//add new post }

Maybe if you use something like a wpdb query including the wp_posts and wp_postmeta searching this meta before inserting the post...

$string = 'the_url.html';
$output = $wpdb->get_var($wpdb->prepare("SELECT count(id)
            FROM $wpdb->posts wpo, $wpdb->postmeta wpm
            WHERE wpo.ID = wpm.post_id
            AND wpm.meta_key = 'name_of_ur_meta'
            AND wpm.meta_value = '$string'"));      
if(empty($output)) {
    /* Insert your post */
    } else {
            /* Update the post or do other thing */
    };