• Temporary remove all eventual HTML tags
• Trim stripped content at desired words length
• Get all HTML tags back on their initial positions
• Watch for unclosed tags

OK, I guess the task is quite clear. Now we gonna create a function, paste it at the bottom of ‘functions.php’ so it can be (re)used whenever is needed. I didn’t want to bother with making widget or plugin coz it takes more time and does the same job. Maybe one day I will. Here is our function:

<?php
function trim_the_content( $the_contents, $read_more_tag = ' READ MORE...', $perma_link_to = '', $all_words = 45 ) {
	// make the list of allowed tags
	$allowed_tags = array( 'a', 'abbr', 'b', 'blockquote', 'b', 'cite', 'code', 'div', 'em', 'fon', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'img', 'label', 'i', 'p', 'pre', 'span', 'strong', 'title', 'ul', 'ol', 'li', 'object', 'embed' );
	if( $the_contents != '' ) {
		// process allowed tags
		$allowed_tags = '<' . implode( '><', $allowed_tags ) . '>';
		$the_contents = str_replace( ']]>', ']]&gt;', $the_contents );
		$the_contents = strip_tags( $the_contents, $allowed_tags );
		// exclude HTML from counting words
		if( $all_words > count( preg_split( '/[\s]+/', strip_tags( $the_contents ), -1 ) ) ) return $the_contents;
		// count all
		$all_chunks = preg_split( '/([\s]+)/', $the_contents, -1, PREG_SPLIT_DELIM_CAPTURE );
		$the_contents = '';
		$count_words = 0;
		$enclosed_by_tag = false;
		foreach( $all_chunks as $chunk ) {
			// is tag opened?
			if( 0 < preg_match( '/<[^>]*$/s', $chunk ) ) $enclosed_by_tag = true;
			elseif( 0 < preg_match( '/>[^<]*$/s', $chunk ) ) $enclosed_by_tag = false;
			// get entire word
			if( !$enclosed_by_tag && '' != trim( $chunk ) && substr( $chunk, -1, 1 ) != '>' ) $count_words ++;
			$the_contents .= $chunk;
			if( $count_words >= $all_words && !$enclosed_by_tag ) break;
		}
                // note the class named 'more-link'. style it on your own
		$the_contents = $the_contents . '<a class="more-link" href="' . $perma_link_to . '">' . $read_more_tag . '</a>';
		// native WordPress check for unclosed tags
		$the_contents = force_balance_tags( $the_contents );
	}
	return $the_contents;
}
?>

How to use this code with your own theme templates?

That’s easy, the only thing you need to do is to call our function (pasted in functions.php, remember?) and pass required arguments or parameters. For example…instead of using either the_excerpt() or the_content() WP’s functions you would write something like this:

<?php
	// find out your post permalink
	$perma_link = get_permalink( $post->ID );
	// save original post content to variable
	$content = get_the_content();
	// prevent tags strip | it's a bug in WordPress!
	$content = apply_filters( 'the_content', $content );
	$content = str_replace( ']]>', ']]&gt;', $content );
	// throw out trimmed: content to process, read more tag, post permalink, words length
	echo trim_the_content( $content, 'READ MORE...', $perma_link, 45 );
?>

Hopefully you find this function useful so share it with others PLEASE! Thanks!

The code

Please note that I have created new WordPress template file and save it as ’sitemap.php’ in theme’s root folder. For more info regarding custom WP template files and how to use them, please refer to this page.
Also, another important info is that this code will work only for Custom Permalink structure set to /%category%/%postname%/.

<?php
    // easy job for pages...
    echo '<ul>';
    echo '<li><h1>PAGES:</h1></li>';
    echo '<li><ul>';
    wp_list_pages( 'title_li=&echo=1' );
    echo '</ul></li></ul>';

    // categories sitemap will be tough...get'em all
    $subcats = wp_list_categories( 'echo=0&use_desc_for_title=0&title_li=' );
    // anybody there?
    preg_match_all( '|<a.*?href=[\'"](.*?)[\'"].*?>|i', $subcats, $m );
	if( !$m[ 1 ] ) {
		// no categs, subcategs or whatsoever...
		echo "There are no categories added to your WordPress site.";
	} else {
		$arr_categories = array();
		$arr_orig_urls  = array();
		foreach( $m[ 1 ] as $key => $value ) {
			// $value will keep the URL, extract category slug
			$arr_of_url = explode( '/', $value );
			array_pop( $arr_of_url ); // remove empty
			// push the last
			array_push( $arr_categories, $arr_of_url[ count( $arr_of_url ) - 1 ] );
			// get its URL
			array_push( $arr_orig_urls, $value );
		}
	}

	if( count( $arr_categories ) > 0 ) {
		// now we have entire logical structure of all categories
		// let's try to get ID for each of these
		echo '<ul>';
		echo '<li><h1>CATEGORIES:</h1></li>';
		$i = 0;
		while( $i < count( $arr_categories ) ) {
			// shortcut by WP built-in
			$idObj = get_category_by_slug( $arr_categories[ $i ] );
			$catid = $idObj->term_id;

			// check whether this is root category. If true, make an outset in list, otherwise leave inset.
			if( $idObj->category_parent > 0 ) echo '<li><ul>';

			// get category real name and link
			$cat_real_name = $wpdb->get_var( "SELECT name FROM $wpdb->terms WHERE term_id=" . $catid );
			echo '<li><h2><a href="' . $arr_orig_urls[ $i ] . '">' . $cat_real_name . '</a></h2></li>';

			// generate list of posts
			echo '<li><ul>';
			query_posts( 'cat=' . $catid  . '&order=ASC' ); // change to DESC - if required
			while( have_posts() ) : the_post();
?>

<li><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></li>
<?php
			endwhile;
			echo '</ul></li>';
			if( $idObj->category_parent > 0 ) echo '</ul></li>';
			$i ++;
		}
	echo '</ul>';
	}
?>

Hopefully you will find this code useful. Any comment/suggestion regarding improvement is welcome!