How to parse user search string for Postgresql query?

Question

i created a search engine on my site using full text search in Postegresql. i added a searchbox in my PHP page in which users can write strings like these:

word1 +word2
word1+word2
word1    -word2
 word1-word2
word1 word2
word1  word2

how to convert them to the following strings?

word1&word2
word1&word2
word1&!word2
word1&!word2
word1|word2
word1|word2

i tried several solutions but none works with all cases. The last one i tried is the following:

    $user_query_string = trim($_GET['search']);
    $final_query_string = str_replace(array('+', ' ', '-'), array('&','|', '&!'), $user_query_string);

Answer 1

Try this:

$a=array('word1 +word2','word1+word2','word1    -word2',' word1-word2','word1 word2','word1  word2');

foreach ($a as &$v) {
  $v=preg_replace('/ +/','|',        // last: change blanks to |
     preg_replace('/ *(?=[!&])/','', // delete blanks before ! or &
     strtr(trim($v),array('-'=>'&!','+'=>'&'))  // turn + and - into & and !&
     ));
}
print_r($a);

This will give:

Array
(
    [0] => word1&word2
    [1] => word1&word2
    [2] => word1&!word2
    [3] => word1&!word2
    [4] => word1|word2
    [5] => word1|word2
)