class.ilQueryParser.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program is free software; you can redistribute it and/or               |
        | modify it under the terms of the GNU General Public License                 |
        | as published by the Free Software Foundation; either version 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program is distributed in the hope that it will be useful,             |
        | but WITHOUT ANY WARRANTY; without even the implied warranty of              |
        | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               |
        | GNU General Public License for more details.                                |
        |                                                                             |
        | You should have received a copy of the GNU General Public License           |
        | along with this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/

define('QP_COMBINATION_AND','and');
define('QP_COMBINATION_OR','or');

class ilQueryParser
{
        var $lng = null;

        var $min_word_length = 0;


        var $query_str;
        var $quoted_words = array();
        var $message; // Translated error message
        var $combination; // combiniation of search words e.g 'and' or 'or'
        protected $settings = null;

        function ilQueryParser($a_query_str)
        {
                global $lng;

                define(MIN_WORD_LENGTH,3);

                $this->lng =& $lng;

                $this->query_str = $a_query_str;
                $this->message = '';

                include_once './Services/Search/classes/class.ilSearchSettings.php';
                $this->settings = new ilSearchSettings();

                if(!$this->setMinWordLength(1))
                {
                        $this->setMinWordLength(MIN_WORD_LENGTH);
                }
        }

        function setMinWordLength($a_length,$a_force = false)
        {
                // Due to a bug in mysql fulltext search queries with min_word_legth < 3
                // might freeze the system.
                // Thus min_word_length cannot be set to values < 3 if the mysql fulltext is used.
                if(!$a_force and $this->settings->enabledIndex() and $a_length < 3)
                {
                        $GLOBALS['ilLog']->write(__METHOD__.': Disabled min word length');
                        return false;                   
                }
                $this->min_word_length = $a_length;
                return true;
        }
        function getMinWordLength()
        {
                return $this->min_word_length;
        }

        function setMessage($a_msg)
        {
                $this->message = $a_msg;
        }
        function getMessage()
        {
                return $this->message;
        }
        function appendMessage($a_msg)
        {
                if(strlen($this->getMessage()))
                {
                        $this->message .= '<br />';
                }
                $this->message .= $a_msg;
        }

        function setCombination($a_combination)
        {
                $this->combination = $a_combination;
        }
        function getCombination()
        {
                return $this->combination;
        }

        function getQueryString()
        {
                return trim($this->query_str);
        }
        function getWords()
        {
                return $this->words ? $this->words : array();
        }

        function getQuotedWords($with_quotation = false)
        {
                if($with_quotation)
                {
                        return $this->quoted_words ? $this->quoted_words : array();
                }
                else
                {
                        foreach($this->quoted_words as $word)
                        {
                                $tmp_word[] = str_replace('\"','',$word);
                        }
                        return $tmp_word ? $tmp_word : array();
                }
        }

        function getLuceneQueryString()
        {
                $counter = 0;
                $tmp_str = "";
                foreach($this->getQuotedWords(true) as $word) {
                        if($counter++)
                        {
                                $tmp_str .= (" ".strtoupper($this->getCombination())." ");
                        }
                        $tmp_str .= $word;
                }
                return $tmp_str;
        }
        function parse()
        {
                $this->words = array();

                #if(!strlen($this->getQueryString()))
                #{
                #       return false;
                #}

                $words = explode(' ',trim($this->getQueryString()));
                foreach($words as $word)
                {
                        if(!strlen(trim($word)))
                        {
                                continue;
                        }
                        
                        if(strlen(trim($word)) < $this->getMinWordLength())
                        {
                                $this->setMessage($this->lng->txt('search_minimum_three'));
                                continue;
                        }
                        $this->words[] = ilUtil::prepareDBString($word);
                }

                // Parse strings like && 'A "B C D" E' as 'A' && 'B C D' && 'E'
                // Can be used in LIKE search or fulltext search > MYSQL 4.0
                $this->__parseQuotation();

                return true;
        }

        function __parseQuotation()
        {
                if(!strlen($this->getQueryString()))
                {
                        $this->quoted_words[] = '';
                        return false;
                }
                $query_str = $this->getQueryString();
                while(preg_match("/\".*?\"/",$query_str,$matches))
                {
                        $query_str = str_replace($matches[0],'',$query_str);
                        $this->quoted_words[] = ilUtil::prepareDBString($matches[0]);
                }

                // Parse the rest
                $words = explode(' ',trim($query_str));
                foreach($words as $word)
                {
                        if(!strlen(trim($word)))
                        {
                                continue;
                        }
                        $this->quoted_words[] = ilUtil::prepareDBString($word);
                }
                
        }

        function validate()
        {
                // Words with less than 3 characters
                if(strlen($this->getMessage()))
                {
                        return false;
                }
                // No search string given
                if($this->getMinWordLength() and !count($this->getWords()))
                {
                        $this->setMessage($this->lng->txt('msg_no_search_string'));
                        return false;
                }

                return true;
        }
}
?>