WAP capability | Permalink redirect to function | Post-content enhancement

Hi everyone!

Unfortunately the search didn’t help me too much since I do not really know what to search for.

I have this idea to also serve my latest post as a wml file to make this available to old WAP-capable phones (wikipedia).
So I started to make a php-file that puts out a wml for this task. But well it didn’t work as expected.

First problem: I get this error message when opening up the php-file directly:

Warning: session_start(): Cannot send session cache limiter – headers already sent […]

Thus I assume it would be best to have a function that I can put in my theme’s functions.php that creates my file once it is demanded, right?
But how do I create such virtual files (I know WordPress does so with the robot.txt)?

Second problem: I need a url that triggers the function.
For example: If someone goes to “https://www.mysite.com/wap” the function should be triggered and the virtual file should be sended.

Third problem (probably the easiest): Since these old phones cannot handle images and are only capable of very basic mark-up I want to fetch only the text of a post without any formatting nor images (no caption, no h2, no nothing). How do I do that?

This is what I have so far. Hacked together from different sources. I currently resides in my theme folder. I put this here just to get you the idea of what I’m trying to do:

<?php
	header('text/vnd.wap.wml;charset=utf-8');
	echo "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>";
	require('../../../wp-config.php');

	/**
	* Extract the base path out of the current path
	*/
	function hide_server_url( $path ) {
		$site_url = get_site_url();
		if (substr($path, 0, strlen($site_url)) != $site_url) return $path;

		$trimmed = substr($path, strlen($site_url));
		while (substr($trimmed,0,1) == '/') $trimmed = substr($trimmed,1);
		while (substr($trimmed, strlen($trimmed)-1) == '/') $trimmed = substr($trimmed, 0, strlen($trimmed)-1);

		return $trimmed;
	}
?>

<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.3//EN" "https://www.wapforum.org/DTD/wml13.dtd">

<wml>
<card id="home" title="Econore">
<img src="library/images/econore.wbmp" />
<p>WELCOME<br />The News:</p>

	<?php query_posts('post_type=page&showposts=1&orderby=menu_order&post_status=publish'); while (have_posts()) : the_post(); ?>
		<page id="<?php the_ID(); ?>" path="<?php echo hide_server_url(get_permalink()); ?>" template="<?php echo get_post_meta($post->ID,'_wp_page_template',true); ?>">
			<h1><![CDATA[<?php echo $post->post_title; ?>]]></h1>
			<p><![CDATA[<?php echo $post->post_content; ?>]]></p>
		</page>
	<?php endwhile; wp_reset_query(); ?>

</card>
</wml>