How to generate the snippet like those generated by Google with PHP and MySQL?

Question

For example, it just returns the snippet around which the searching keyword exists.

And part of the text is replaced by "...".

Is it possible to achieve that goal with PHP and MySQL?

Answer 1

Modified deceze's function slightly to allow multiple phrases. e.g. your phrase can be "testa testb" and if it does not find testa, then it will go to testb.

function excerpt($text, $phrase, $radius = 100, $ending = "...") { 


         $phraseLen = strlen($phrase); 
       if ($radius < $phraseLen) { 
             $radius = $phraseLen; 
         } 

         $phrases = explode (' ',$phrase);

         foreach ($phrases as $phrase) {
             $pos = strpos(strtolower($text), strtolower($phrase)); 
             if ($pos > -1) break;
         }

         $startPos = 0; 
         if ($pos > $radius) { 
             $startPos = $pos - $radius; 
         } 

         $textLen = strlen($text); 

         $endPos = $pos + $phraseLen + $radius; 
         if ($endPos >= $textLen) { 
             $endPos = $textLen; 
         } 

         $excerpt = substr($text, $startPos, $endPos - $startPos); 
         if ($startPos != 0) { 
             $excerpt = substr_replace($excerpt, $ending, 0, $phraseLen); 
         } 

         if ($endPos != $textLen) { 
             $excerpt = substr_replace($excerpt, $ending, -$phraseLen); 
         } 

         return $excerpt; 
   } 

Highlight function

function highlight($c,$q){ 
$q=explode(' ',str_replace(array('','\\','+','*','?','[','^',']','$','(',')','{','}','=','!','<','>','|',':','#','-','_'),'',$q));
for($i=0;$i<sizeOf($q);$i++) 
    $c=preg_replace("/($q[$i])(?![^<]*>)/i","<span class=\"highlight\">\${1}</span>",$c);
return $c;}

Answer 2

My solution for multiple multiple keywords and multiple occurences (also works for accents case insensitive):

function excerpt($text, $query)
{
//words
$words = join('|', explode(' ', preg_quote($query)));

//lookahead/behind assertions ensures cut between words
$s = '\s\x00-/:-@\[-`{-~'; //character set for start/end of words
preg_match_all('#(?<=['.$s.']).{1,30}(('.$words.').{1,30})+(?=['.$s.'])#uis', $text, $matches, PREG_SET_ORDER);

//delimiter between occurences
$results = array();
foreach($matches as $line) {
    $results[] = htmlspecialchars($line[0], 0, 'UTF-8');
}
$result = join(' <b>(...)</b> ', $results);

//highlight
$result = preg_replace('#'.$words.'#iu', "<span class=\"highlight\">\$0</span>", $result);

return $result;
}

This is example result for query = "švihov prohlídkám"