Parse XML into Wordpress WYSIWYG editor ONLY for Posts - php

Question

I've run into a little situation that is hopefully possible to solve. My goal is to take an existing XML file from the server, parse it, and then inject it as a list into Wordpress's original WYSIWYG editor so that the site owner has the list readily available when he writes a new post. Right now, I have this code in my wp-admin/edit-form-advanced.php file:
/**
* Fires after the title field.
*
* #since 3.5.0
*
* #param WP_Post $post Post object.
*/
do_action( 'edit_form_after_title', $post );
if ( post_type_supports($post_type, 'editor') ) {
?>
<div id="postdivrich" class="postarea<?php if ( $_wp_editor_expand ) { echo ' wp-editor-expand'; } ?>">
<?php
/** LOAD XML FROM SERVER AND PARSE AS UL INTO EACH NEW WP POST **/
$xml = simplexml_load_file('../my-folder/file.xml');
$product = "<br/><br/><h2 style='text-align:center; color:#003300;'><u>Products Available Now</u></h2><br/><ul style='text-align:center; list-style:none; color:#003300;'>";
foreach( $xml as $value ) {
$product .= "<li>";
$product .= $value->Description .= " $";
$product .= $value->Price .= " / ";
$product .= $value->QtyUnit .= "\n";
$product .= "</li>";
};
?>
<?php wp_editor($product, 'content', array(
'_content_editor_dfw' => $_content_editor_dfw,
'drag_drop_upload' => true,
'tabfocus_elements' => 'content-html,save-post',
'editor_height' => 300,
'tinymce' => array(
'resize' => false,
'wp_autoresize_on' => $_wp_editor_expand,
'add_unload_trigger' => false,
),
) ); ?>
Although it works, this causes a couple issues.
1) It injects the data into every WYSIWYG editor, including pages, which I would like to avoid. The content should only appear in post editors if possible.
2) It causes a pretty serious bug that erases anything but the list whenever that particular admin page is reloaded. I can't save any drafts, or edit posts or pages unless I keep that session open in the browser during the editing process.
Not sure if these issues can be solved, but any and all help is sincerely appreciated!!

Answer 1

You should never modify WP core files. It's advisable that you update or restore the original files.
What you need can be achieved with this little plugin:
<?php
/**
* Plugin Name: Default Post Content
*/
add_action( 'load-post-new.php', 'new_post_so_44123076' );
function new_post_so_44123076() {
# Only load if post type not defined (only occurs for Posts)
if( isset($_GET['post_type']) )
return;
add_filter( 'default_content', 'default_content_so_44123076' );
}
function default_content_so_44123076( $content ) {
# Build your own custom content
$content = "My html content.";
return $content;
}
Make a folder for the plugin, put the code inside a file (custom-content.php) and put the XML on the same folder.
It can be retrieved like this:
$xml = plugins_url( '/file.xml', __FILE__ );