Wordpress add_meta_box() weirdness - php

Question

The code below is working nearly flawlessly, however my value for page title on one of my pages keeps coming up empty after a few page refreshes... It sticks for awhile, then it appears to reset to empty. I'm thinking I must have a conflict in the code below, but I can't quite figure it.
I'm allowing the user to set a custom page title for posts as well as pages via a custom "post/page title input field). Can anyone see an obvious issue here that might be resetting the page title to blank?
// ===================
// = POST OPTION BOX =
// ===================
add_action('admin_menu', 'my_post_options_box');
function my_post_options_box() {
if ( function_exists('add_meta_box') ) {
//add_meta_box( $id, $title, $callback, $page, $context, $priority );
add_meta_box('post_header', 'Custom Post Header Code (optional)', 'custom_post_images', 'post', 'normal', 'low');
add_meta_box('post_title', 'Custom Post Title', 'custom_post_title', 'post', 'normal', 'high');
add_meta_box('post_title_page', 'Custom Post Title', 'custom_post_title', 'page', 'normal', 'high');
add_meta_box('postexcerpt', __('Excerpt'), 'post_excerpt_meta_box', 'page', 'normal', 'core');
add_meta_box('categorydiv', __('Page Options'), 'post_categories_meta_box', 'page', 'side', 'core');
}
}
//Adds the custom images box
function custom_post_images() {
global $post;
?>
<div class="inside">
<textarea style="height:70px; width:100%;margin-left:-5px;" name="customHeader" id="customHeader"><?php echo get_post_meta($post->ID, 'customHeader', true); ?></textarea>
<p>Enter your custom html code here for the post page header/image area. Whatever you enter here will override the default post header or image listing <b>for this post only</b>. You can enter image references like so <img src='wp-content/uploads/product1.jpg' />. To show default images, just leave this field empty</p>
</div>
<?php
}
//Adds the custom post title box
function custom_post_title() {
global $post;
?>
<div class="inside">
<p><input style="height:25px;width:100%;margin-left:-10px;" type="text" name="customTitle" id="customTitle" value="<?php echo get_post_meta($post->ID, 'customTitle', true); ?>"></p>
<p>Enter your custom post/page title here and it will be used for the html <title> for this post page and the Google link text used for this page.</p>
</div>
<?php
}
add_action('save_post', 'custom_add_save');
function custom_add_save($postID){
if (!defined('DOING_AUTOSAVE') && !DOING_AUTOSAVE) {
return $postID;
}
else
{
// called after a post or page is saved and not on autosave
if($parent_id = wp_is_post_revision($postID))
{
$postID = $parent_id;
}
if ($_POST['customHeader'])
{
update_custom_meta($postID, $_POST['customHeader'], 'customHeader');
}
else
{
update_custom_meta($postID, '', 'customHeader');
}
if ($_POST['customTitle'])
{
update_custom_meta($postID, $_POST['customTitle'], 'customTitle');
}
else
{
update_custom_meta($postID, '', 'customTitle');
}
}
}
function update_custom_meta($postID, $newvalue, $field_name) {
// To create new meta
if(!get_post_meta($postID, $field_name)){
add_post_meta($postID, $field_name, $newvalue);
}else{
// or to update existing meta
update_post_meta($postID, $field_name, $newvalue);
}
}
?>

Answer 1

Wordpress's auto save system may well be your problem, as I think custom fields are not passed along for auto saves (so your customHeader and customTitle post variables will be empty during an auto save).
In your save function you should check if the DOING_AUTOSAVE constant is set (this seems to be preferable to checking the post action) and return if so. Something like this:
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) return;
See this ticket for more info: http://core.trac.wordpress.org/ticket/10744

Answer 2

The WordPress Codex has got an function reference for add_meta_box(), with a great example.
And yes, it uses
if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE )
return $post_id;
and I think you've implemented it the right way.

Answer 3

FYI, the solution posted here http://wordpress.org/support/topic/custom-post-type-information-disappearing worked for me and I think is much more elegant.