Developmen reboot

Hello Arjan
I’m glad to hear that this plugin will continue to be maintained and developed. Thank you very much!
It would be great if it were possible to select individual custom post types as a target. I have already implemented this in an amateurish way.
Greetings
Bernhard

This is the “wpa-seo-auto-linker.php” with my changes:

<?php
/*
Plugin Name: WPA SEO Auto Linker
Plugin URI: https://www.wpassist.tech/wordpress-plugins/wpa-seo-auto-linker/
Version: 1.2
Author: Arjan Olsder
Author URI: https://www.wpassist.tech
Description: <strong>!! A C H T U N G : ?nderungen von BH: 1.) Query-Limit von 2000 auf 20000 erh?ht -> suche "LIMIT 2000" -- 2.) teilweise Erweiterung des Plugins auf custom_post_types (suche "customposttypes"). </strong>WPA SEO Auto Linker is based on the original SEO Auto Links plugin by Maarten Brakkee. It allows you to setup a list of keywords with default internal and external links. Development of the original plugin seems to have ended as it broke after migrating to PHP 7. If you have a deactivated version of the original plugin, keep it deactivated. Install this one and the original settings will be used.
*/

if ( !class_exists('SEOAutoLinks') ) :
	
class SEOAutoLinks {
	var $SEOAutoLinks_DB_option = 'SEOAutoLinks';
	var $SEOAutoLinks_options; 
	
	function SEOAutoLinks() {	
	  $options = $this->get_options();
	  if ($options) {
			if ($options['post'] || $options['page'] || $options['customposttype'])		
				add_filter('the_content',  array(&$this, 'SEOAutoLinks_the_content_filter'), 10);	
			if ($options['comment'])						
				add_filter('comment_text', array(&$this, 'SEOAutoLinks_comment_text_filter'), 10);	
		}
		add_action('create_category', array(&$this, 'SEOAutoLinks_delete_cache'));
		add_action('edit_category', array(&$this,'SEOAutoLinks_delete_cache'));
		add_action('edit_post', array(&$this,'SEOAutoLinks_delete_cache'));
		add_action('save_post', array(&$this,'SEOAutoLinks_delete_cache'));
		add_action('admin_menu', array(&$this, 'SEOAutoLinks_admin_menu'));
		load_plugin_textdomain('wpa-seo-auto-linker', false, dirname( plugin_basename( __FILE__ ) ) . '/languages/');
		add_action('admin_enqueue_scripts', array(&$this, 'SEOAutoLinks_admin_menu_load_scripts'));
	}

function SEOAutoLinks_process_text($text, $mode) {

	global $wpdb, $post;
	
	$options = $this->get_options();
	$links=0;
	
	if (is_feed() && !$options['allowfeed'])
		return $text;
	else if ($options['onlysingle'] && !(is_single() || is_page()))
		return $text;
        
    $arrignorepost=$this->explode_trim(",", ($options['ignorepost']));
	
    if (is_page($arrignorepost) || is_single($arrignorepost)) {
        return $text;
    }
    
	if (!$mode) {
		if ($post->post_type=='post' && !$options['post'])
			return $text;
		else if ($post->post_type=='page' && !$options['page'])
			return $text;
		
		if (($post->post_type=='page' && !$options['pageself']) || ($post->post_type=='post' && !$options['postself'])) {
			$thistitle=$options['casesens'] ? $post->post_title : strtolower($post->post_title);
			$thisurl=trailingslashit(get_permalink($post->ID));
		} else {
			$thistitle='';
			$thisurl='';
		}
	}

	$maxlinks=($options['maxlinks']>0) ? $options['maxlinks'] : 0;	
	$maxsingle=($options['maxsingle']>0) ? $options['maxsingle'] : -1;
	$maxsingleurl=($options['maxsingleurl']>0) ? $options['maxsingleurl'] : 0;
	$minusage = ($options['minusage']>0) ? $options['minusage'] : 1;

	$urls = array();
		
	$arrignore=$this->explode_trim(",", ($options['ignore']));
	if ($options['excludeheading'] == "on") {
		 $text = preg_replace_callback('%(<h.*?>)(.*?)(</h.*?>)%si',
   function($m) { 
      return $m[1].SEOAutoInSpecChar($m[2]).$m[3];
    },
       $text
    );
	}
	
	$reg_post		=	$options['casesens'] ? '/(?!(?:[^<\[]+[>\]]|[^>\]]+<\/a>))($name)/msU' : '/(?!(?:[^<\[]+[>\]]|[^>\]]+<\/a>))($name)/imsU';	
	$reg			=	$options['casesens'] ? '/(?!(?:[^<\[]+[>\]]|[^>\]]+<\/a>))\b($name)\b/msU' : '/(?!(?:[^<\[]+[>\]]|[^>\]]+<\/a>))\b($name)\b/imsU';
	$strpos_fnc		=	$options['casesens'] ? 'strpos' : 'stripos';
	
	$text = " $text ";

    if (!empty($options['customkey_url'])) {
        $now = time();
		
        if ($options['customkey_url_datetime']){
            $last_update = $options['customkey_url_datetime'];
        } else {
            $last_update = 0;
        }
		
        if ($now - $last_update > 86400) {
            $body = wp_remote_retrieve_body(wp_remote_get($options['customkey_url']));
            $options['customkey_url_value'] = strip_tags($body);
            $options['customkey_url_datetime'] = $now;
            update_option($this->SEOAutoLinks_DB_option, $options);
        }
		
        $options['customkey'] = $options['customkey'] . "\n" . $options['customkey_url_value'];
    }
	
	// custom keywords
	if (!empty($options['customkey'])) {		
		$kw_array = array();
		
		foreach (explode("\n", $options['customkey']) as $line) {
			if($options['customkey_preventduplicatelink'] == TRUE) {
				$line = trim($line);
				$lastDelimiterPos=strrpos($line, ',');
				$url = substr($line, $lastDelimiterPos + 1 );
				$keywords = substr($line, 0, $lastDelimiterPos);
				
				if(!empty($keywords) && !empty($url)){
					$kw_array[$keywords] = $url;
				}
				
				$keywords='';
				$url='';
			} else {
				$chunks = array_map('trim', explode(",", $line));
				$total_chuncks = count($chunks);
				if($total_chuncks > 2) {
					$i = 0;
					$url = $chunks[$total_chuncks-1];
					while($i < $total_chuncks-1) {
						if (!empty($chunks[$i])) $kw_array[$chunks[$i]] = $url;
							$i++;
					}
				} else {
					list($keyword, $url) = array_map('trim', explode(",", $line, 2));
					if (!empty($keyword)) $kw_array[$keyword] = $url;
				}	
			}
		}
		
		foreach ($kw_array as $name=>$url) {
			if ((!$maxlinks || ($links < $maxlinks)) && (trailingslashit($url)!=$thisurl) && !in_array( $options['casesens'] ? $name : strtolower($name), $arrignore) && (!$maxsingleurl || $urls[$url]<$maxsingleurl) ) {
				if (($options['customkey_preventduplicatelink'] == TRUE) || $strpos_fnc($text, $name) !== false) {
					$name= preg_quote($name, '/');
					if($options['customkey_preventduplicatelink'] == TRUE) $name = str_replace(',','|',$name); //Modifying RegExp for count all grouped keywords as the same one
					
					$replace="<a title=\"$1\" href=\"$url\">$1</a>";
					$regexp=str_replace('$name', $name, $reg);	
					$newtext = preg_replace($regexp, $replace, $text, $maxsingle);			
					if ($newtext!=$text) {							
						$links++;
						$text=$newtext;
                        if (!isset($urls[$url])) $urls[$url]=1; else $urls[$url]++;
					}	
				}
			}		
		}
	}

	
	// posts and pages - BH: oder erweitern, so dass costum post types auch funktionieren wenn post && page ausgeschaltet sind
	if ($options['lposts'] || $options['lpages'] || $options['lcustomposttypes']) {
		if ( !$posts = wp_cache_get( 'seo-links-posts', 'wpa-seo-auto-linker' ) ) {
			$query="SELECT post_title, ID, post_type FROM $wpdb->posts WHERE post_status = 'publish' AND LENGTH(post_title)>3 ORDER BY LENGTH(post_title) DESC LIMIT 20000";
			$posts = $wpdb->get_results($query);
			wp_cache_add( 'seo-links-posts', $posts, 'wpa-seo-auto-linker', 86400 );
		}
	
		foreach ($posts as $postitem) {
			// BH: folgendes if options ODER erweitert mit $postitem->post_type!= ...											  
			if ((($options['lposts'] && $postitem->post_type=='post') || ($options['lpages'] && $postitem->post_type=='page')
			|| ($postitem->post_type!='post' && $postitem->post_type!='page' && $options['lcustomposttypes'])
			) &&
			(!$maxlinks || ($links < $maxlinks))  && (($options['casesens'] ? $postitem->post_title : strtolower($postitem->post_title))!=$thistitle) && (!in_array( ($options['casesens'] ? $postitem->post_title : strtolower($postitem->post_title)), $arrignore))) {
				if ($strpos_fnc($text, $postitem->post_title) !== false) {		// credit to Dominik Deobald
					$name = preg_quote($postitem->post_title, '/');		
					
					$regexp=str_replace('$name', $name, $reg);	
					$replace='<a title="$1" href="$$$url$$$">$1</a>';
				
					$newtext = preg_replace($regexp, $replace, $text, $maxsingle);
					if ($newtext!=$text) {		
						$url = get_permalink($postitem->ID);
						if (!$maxsingleurl || $urls[$url]<$maxsingleurl) {
						  $links++;
						  $text=str_replace('$$$url$$$', $url, $newtext);	
						  if (!isset($urls[$url])) $urls[$url]=1; else $urls[$url]++;
						}
					}
				}
			}
		}
	}
	
	// categories
	if ($options['lcats']) {
		if ( !$categories = wp_cache_get( 'seo-links-categories', 'wpa-seo-auto-linker' ) ) {
			$query="SELECT $wpdb->terms.name, $wpdb->terms.term_id FROM $wpdb->terms LEFT JOIN $wpdb->term_taxonomy ON $wpdb->terms.term_id = $wpdb->term_taxonomy.term_id WHERE $wpdb->term_taxonomy.taxonomy = 'category'  AND LENGTH($wpdb->terms.name)>3 AND $wpdb->term_taxonomy.count >= $minusage ORDER BY LENGTH($wpdb->terms.name) DESC LIMIT 20000";
			$categories = $wpdb->get_results($query);
			wp_cache_add( 'seo-links-categories', $categories, 'wpa-seo-auto-linker',86400 );
		}
	
		foreach ($categories as $cat) {
			if ((!$maxlinks || ($links < $maxlinks)) &&  !in_array( $options['casesens'] ?  $cat->name : strtolower($cat->name), $arrignore)) {
				if ($strpos_fnc($text, $cat->name) !== false) {		// credit to Dominik Deobald
					$name= preg_quote($cat->name, '/');	
					$regexp=str_replace('$name', $name, $reg);	;
					$replace='<a title="$1" href="$$$url$$$">$1</a>';
				
					$newtext = preg_replace($regexp, $replace, $text, $maxsingle);
					if ($newtext!=$text) {						
						$url = (get_category_link($cat->term_id));	
						if (!$maxsingleurl || $urls[$url]<$maxsingleurl) {			
						  $links++;
						  $text=str_replace('$$$url$$$', $url, $newtext);
						  if (!isset($urls[$url])) $urls[$url]=1; else $urls[$url]++;
						}
					}
				}
			}		
		}
	}
	
	// tags
	if ($options['ltags']) {
		if ( !$tags = wp_cache_get( 'seo-links-tags', 'wpa-seo-auto-linker' ) ) {
			$query="SELECT $wpdb->terms.name, $wpdb->terms.term_id FROM $wpdb->terms LEFT JOIN $wpdb->term_taxonomy ON $wpdb->terms.term_id = $wpdb->term_taxonomy.term_id WHERE $wpdb->term_taxonomy.taxonomy = 'post_tag'  AND LENGTH($wpdb->terms.name)>3 AND $wpdb->term_taxonomy.count >= $minusage ORDER BY LENGTH($wpdb->terms.name) DESC LIMIT 20000";	
			$tags = $wpdb->get_results($query);
			wp_cache_add( 'seo-links-tags', $tags, 'wpa-seo-auto-linker',86400 );
		}
		
		foreach ($tags as $tag) {
			if ((!$maxlinks || ($links < $maxlinks)) && !in_array( $options['casesens'] ? $tag->name : strtolower($tag->name), $arrignore) ) {
				if ($strpos_fnc($text, $tag->name) !== false) {		// credit to Dominik Deobald
					$name = preg_quote($tag->name, '/');	
					$regexp=str_replace('$name', $name, $reg);	;
					$replace='<a title="$1" href="$$$url$$$">$1</a>';
									
					$newtext = preg_replace($regexp, $replace, $text, $maxsingle);
					if ($newtext!=$text) {
						$url = (get_tag_link($tag->term_id));
						if (!$maxsingleurl || $urls[$url]<$maxsingleurl) {			
						  $links++;
						  $text=str_replace('$$$url$$$', $url, $newtext);
                          if (!isset($urls[$url])) $urls[$url]=1; else $urls[$url]++;
						}
					}
				}
			}
		}
	}
	
	if ($options['excludeheading'] == "on") {
		
		$text = preg_replace_callback('%(<h.*?>)(.*?)(</h.*?>)%si', function($m) { 
			return $m[1].SEOAutoReSpecChar($m[2]).$m[3];
      	},
      $text
    );
		$text = stripslashes($text);
	}
	return trim( $text );

} 

function SEOAutoLinks_the_content_filter($text) {
	return SEOAutoTextFilter($this->get_options(),$this->SEOAutoLinks_process_text($text, 0));
}

function SEOAutoLinks_comment_text_filter($text) {
	return SEOAutoTextFilter($this->get_options(),$this->SEOAutoLinks_process_text($text, 1));
}
	
function explode_trim($separator, $text) {
    $arr = explode($separator, $text);
    
    $ret = array();
    foreach($arr as $e) {        
      $ret[] = trim($e);        
    }
    return $ret;
}

// Setting default values for fresh installations
function get_options() {
   
	$options = array(
		'post' => 'on',
		'postself' => '',
		'page' => 'on',
		'pageself' => '',
		'comment' => '',
		'excludeheading' => 'on', 
		'lposts' => 'on', 
		'lpages' => 'on',
		'lcustomposttypes' => 'on',
		'lcats' => '', 
		'ltags' => '', 
		'ignore' => 'about', 
		'ignorepost' => 'contact', 
		'maxlinks' => 3,
		'maxsingle' => 1,
		'minusage' => 1,
		'customkey' => '',
		'customkey_preventduplicatelink' => FALSE,
		'customkey_url' => '',
		'customkey_url_value' => '',
		'customkey_url_datetime' => '',
		'nofoln' =>'',
		'nofolo' =>'',
		'blankn' =>'',
		'blanko' =>'',
		'onlysingle' => 'on',
		'casesens' =>'',
		'allowfeed' => '',
		'maxsingleurl' => '1'
	);
 
	$saved = get_option($this->SEOAutoLinks_DB_option);

	if (!empty($saved)) {
		foreach ($saved as $key => $option)
			$options[$key] = $option;
	}

	if ($saved != $options)	
		update_option($this->SEOAutoLinks_DB_option, $options);

	return $options;
}

// Installation script for WPA SEO Auto Linker, registering the options field in the WordPress table with default values
function install() {
	$SEOAutoLinks_options = $this->get_options();
}

function handle_options() {
	$options = $this->get_options();
	if (isset($_POST['submitted']) ) {
		check_admin_referer('wpa-seo-auto-linker');		
		
																					// In order of appearance on the admin form
		
		$options['customkey']		= strip_tags($_POST['customkey']);				// Custom keywords and links
		$options['customkey_preventduplicatelink']=sanitize_key($_POST['customkey_preventduplicatelink']);	// Prevent duplicates
		$options['customkey_url']	= sanitize_text_field($_POST['customkey_url']);	// Load URL's from TXT file
		
		$options['post']			= sanitize_key($_POST['post']);					// Enable posts
		$options['postself']		= sanitize_key($_POST['postself']);				// Enable self linking in posts	
		$options['page']			= sanitize_key($_POST['page']);					// Enable pages
		$options['pageself']		= sanitize_key($_POST['pageself']);				// Enable self linking in pages
		$options['comment']			= sanitize_key($_POST['comment']);				// Enable comments
		$options['allowfeed']		= sanitize_key($_POST['allowfeed']);			// Enable RSS Feeds
		$options['maxlinks']		= sanitize_key($_POST['maxlinks']);				// Max links per post, page etc
		$options['maxsingle']		= sanitize_key($_POST['maxsingle']);			// Max keyword links
		$options['maxsingleurl']	= sanitize_key($_POST['maxsingleurl']);			// Max same URLs
		$options['casesens']		= sanitize_key($_POST['casesens']);				// Toggle case sensitivity
		
		$options['excludeheading']	= sanitize_key($_POST['excludeheading']);		// Exclude headers
		$options['ignorepost']		= sanitize_text_field($_POST['ignorepost']);	// Ignore posts
		$options['ignore']			= sanitize_text_field($_POST['ignore']);		// Ignore keywords
		$options['onlysingle']		= sanitize_key($_POST['onlysingle']);			// Only single, ignore frontpage, archives etc
		
		$options['lposts']			= sanitize_key($_POST['lposts']);				// Auto link post titles
		$options['lpages']			= sanitize_key($_POST['lpages']);				// Auto link page titles
		$options['lcustomposttypes']= sanitize_key($_POST['lcustomposttypes']);		// Auto link custom post types titles
		$options['lcats']			= sanitize_key($_POST['lcats']);				// Auto link category pages
		$options['ltags']			= sanitize_key($_POST['ltags']);				// Auto link tag pages
		$options['minusage']		= sanitize_key($_POST['minusage']);		// Maximum links to post, page etc
		$options['nofoln']			= sanitize_key($_POST['nofoln']);				//
		$options['nofolo']			= sanitize_key($_POST['nofolo']);				// Add rel nofolow to external links
		$options['blankn']			= sanitize_key($_POST['blankn']);				//
		$options['blanko']			= sanitize_key($_POST['blanko']);				// Add target _blank to external links
		
		update_option($this->SEOAutoLinks_DB_option, $options);
		$this->SEOAutoLinks_delete_cache(0);
		echo '<div class="updated"><p>';
		_e('Plugin settings saved.','wpa-seo-auto-linker');
		echo '</p></div>';
	}

	$action_url 	= $_SERVER['REQUEST_URI'];	

	$post			= $options['post']=='on'?'checked':'';
	$postself		= $options['postself']=='on'?'checked':'';
	$page			= $options['page']=='on'?'checked':'';
	$pageself		= $options['pageself']=='on'?'checked':'';
	$comment		= $options['comment']=='on'?'checked':'';
	$excludeheading = $options['excludeheading']=='on'?'checked':'';
	$lposts			= $options['lposts']=='on'?'checked':'';
	$lpages			= $options['lpages']=='on'?'checked':'';
	$lcustomposttypes=$options['lcustomposttypes']=='on'?'checked':'';
	$lcats			= $options['lcats']=='on'?'checked':'';
	$ltags			= $options['ltags']=='on'?'checked':'';
	$ignore			= $options['ignore'];
	$ignorepost		= $options['ignorepost'];
	$maxlinks		= $options['maxlinks'];
	$maxsingle		= $options['maxsingle'];
	$maxsingleurl	= $options['maxsingleurl'];
	$minusage		= $options['minusage'];
	$customkey		= stripslashes($options['customkey']);
	$customkey_url 	= stripslashes($options['customkey_url']);
	$customkey_preventduplicatelink = $options['customkey_preventduplicatelink'] == TRUE ? 'checked' : '';
	$nofoln			= $options['nofoln']=='on'?'checked':'';
	$nofolo			= $options['nofolo']=='on'?'checked':'';
	$blankn			= $options['blankn']=='on'?'checked':'';
	$blanko			= $options['blanko']=='on'?'checked':'';
	$onlysingle		= $options['onlysingle']=='on'?'checked':'';
	$casesens		= $options['casesens']=='on'?'checked':'';
	$allowfeed		= $options['allowfeed']=='on'?'checked':'';

	if (!is_numeric($minusage)) {
		$minusage = 1;
	}
	
	$nonce			= wp_create_nonce('wpa-seo-auto-linker');
	
	/**
	 * Require admin settings page
	 */
	require_once dirname(__FILE__) . '/wpa-seo-auto-linker-admin.php';
}

// Register WPA SEO Auto Linker into the WordPress settings menu
function SEOAutoLinks_admin_menu() {
	global $seoauto_adminmenu;
	$seoauto_adminmenu = add_options_page('WPA SEO Auto Linker Options', 'WPA SEO Auto Linker', 'manage_options', basename(__FILE__), array(&$this, 'handle_options'));
}

// Load styles and javascripts for admin page display
function SEOAutoLinks_admin_menu_load_scripts($hook) {
	global $seoauto_adminmenu;
	if( $hook != $seoauto_adminmenu ) 
		return;
	wp_enqueue_script('tagsjs', plugins_url( '/js/load.js', __FILE__ ) );
	wp_enqueue_style('tagscss', plugins_url( '/css/wpa-seo-auto-linker-style.css', __FILE__ ) );
}

// Delete WPA SEO Auto Linker cache
function SEOAutoLinks_delete_cache($id) {
	wp_cache_delete( 'seo-links-categories', 'wpa-seo-auto-linker' );
	wp_cache_delete( 'seo-links-tags', 'wpa-seo-auto-linker' );
	wp_cache_delete( 'seo-links-posts', 'wpa-seo-auto-linker' );
}

}

endif; 

if (class_exists('SEOAutoLinks') ) :
	$SEOAutoLinks = new SEOAutoLinks();
	if (isset($SEOAutoLinks)) {
		register_activation_hook( __FILE__, array(&$SEOAutoLinks, 'install') );
	}
endif;

	/**
	 * Require WPA SEO Auto Linker functions
	 */
	require_once dirname(__FILE__) . '/wpa-seo-auto-linker-functions.php';
?>

How is it going the PHP 8 compatibility? I want to use that version but I will have to change this plugin if it does not work ??

Believe it or not, SVN was the biggest bottleneck for the new release, but I finally got it working again.

@bhenselmann thanks for sharing this thought/code with us. We will add it to our wishlist for near future development.

@eliasgdj Your wish has been answered. We just published our new code. It’s compliant all the way up to PHP 8.1. Also we have made major improvements on support for pagebuilders. That is, making sure our code doesn’t cause any problems with them (so not rendering in the editor).

Great! I’ll test it out.