Custom Canonical URL

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I'm using concrete5 - 5.6.1.2. I wrote a php function for canonical URL for SEO purpose.

public function canonical($c){
         global $current_domain;       
            $cPath = $c->getCollectionPath(); 
            $canonicalURL = BASE_URL;
            $canonicalURL.= DIR_REL;
              $canonicalURL.= URL_REWRITING?"":"/index.php";
            $canonicalURL.= $cPath;
            $canonicalURL .= "/";
            $pageIndentifierVars = array('keywords','fID','tag','productID'); 
            $canonicalVars = array(); 
            foreach($pageIndentifierVars as $var) 
            if($_REQUEST[$var]) $canonicalVars[]= $var.'='.$_REQUEST[$var]; 
            if( count($canonicalVars) ) $canonicalURL.= '?' . join(',',$canonicalVars);  
            return $canonicalURL;
   }


My C5 pages is like

1. example1
. page1
. page2

2. example2
. page1
. page2

If I add a page to the site, it will be visible at:
example1.com/example1/page1
example2.com/example2/page1

I need to remove that example1,example2 in canonical URL.