wp_insert_post creating duplicate post with Safari

Question

I have a front end form users use to create custom posts. It works fine with Chrome and FF, but when in Safari two posts are created.

The code i'm using is below. I've tried a few conditionals shown in other answers but none worked. How can I prevent wp_insert_post from creating duplicate posts when submitted from Safari?

Thanks

if( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) &&  $_POST['action'] == "new_post") {

$tags = $_POST['post_tags'];

$new_post = array(
    'post_title'    => $title,
    'post_content'  => $description,
    'post_category' => array($_POST['cat']),
    'tags_input'    => array($tags),
    'post_status'   => 'publish',etc.
    'post_type' => 'website'
);

global $current_user;
get_currentuserinfo();

$user_name = strtolower($current_user->user_login);  //custom caps will default to lowercase anyway
$pid = wp_insert_post($new_post);

update_post_meta($pid, "s2member_ccaps_req", $user_name, true);

wp_redirect( get_permalink($pid) ); 
exit();

The form

                <form id="new_post" name="new_post" method="post" action="">
                    <!-- post name -->
                    <p><label for="title">Title</label><br />
                    <input type="text" id="title" value="" tabindex="1" size="20" name="title" />
                    </p>

                    <!-- post Category -->
                    <p><label for="Category">Category:</label><br />
                    <p><?php wp_dropdown_categories( 'tab_index=3&taxonomy=category' ); ?></p>


                    <!-- post Content -->
                    <p><label for="description">Content</label><br />
                    <textarea id="description" tabindex="4" name="description" cols="50" rows="6"></textarea>
                    </p>

                    <!-- post tags -->
                    <p><label for="post_tags">Tags:</label>
                    <input type="text" value="" tabindex="5" size="16" name="post_tags" id="post_tags" /></p>
                    <p align="right"><input type="submit" value="Publish" tabindex="6" id="submit" name="submit" /></p>

                    <input type="hidden" name="action" value="new_post" />
                    <?php wp_nonce_field( 'new-post' ); ?>
                </form>

Answer 1

You could try to use nonces (http://codex.wordpress.org/WordPress_Nonces) in your requests,so even if the request is being sent many times, only 1 time is being saved.

You can add in your form this line

<form method="POST">

    <input type="hidden" name="nonce" value="<?php echo wp_create_nonce( 'form-nonce' );?>" />
    ....
</form>

and in the code where you check :

 $nonce = $_POST['nonce'];
 if ( ! wp_verify_nonce( $nonce, 'form-nonce' ) ) {
     die( 'Security check' ); 
 } else {
     //Your code here
 }