fulltext_mysql.php

这些都是我以前学习是用到的源码

<?php
/** 
*
* @package search
* @version $Id: fulltext_mysql.php,v 1.32 2006/11/27 19:32:18 acydburn Exp $
* @copyright (c) 2005 phpBB Group 
* @license http://opensource.org/licenses/gpl-license.php GNU Public License 
*
*/

/**
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

/**
* @ignore
*/
include_once($phpbb_root_path . 'includes/search/search.' . $phpEx);

/**
* fulltext_mysql
* Fulltext search for MySQL
* @package search
*/
class fulltext_mysql extends search_backend
{
	var $stats = array();
	var $word_length = array();
	var $split_words = array();
	var $search_query;
	var $common_words = array();

	function fulltext_mysql(&$error)
	{
		global $config;

		$this->word_length = array('min' => $config['fulltext_mysql_min_word_len'], 'max' => $config['fulltext_mysql_max_word_len']);

		$error = false;
	}

	/**
	* Checks for correct MySQL version and stores min/max word length in the config
	*/
	function init()
	{
		global $db, $user;

		if (strpos($db->sql_layer, 'mysql') === false)
		{
			return $user->lang['FULLTEXT_MYSQL_INCOMPATIBLE_VERSION'];
		}

		$result = $db->sql_query('SELECT VERSION() AS mysql_version');
		$version = $db->sql_fetchfield('mysql_version');
		$db->sql_freeresult($result);

		if (!preg_match('#^4|5|6#s', $version))
		{
			return $user->lang['FULLTEXT_MYSQL_INCOMPATIBLE_VERSION'];
		}

		$result = $db->sql_query('SHOW TABLE STATUS LIKE \'' . POSTS_TABLE . '\'');
		$info = $db->sql_fetchrow($result);
		$db->sql_freeresult($result);

		$engine = '';
		if (isset($info['Engine']))
		{
			$engine = $info['Engine'];
		}
		else if (isset($info['Type']))
		{
			$engine = $info['Type'];
		}

		if ($engine != 'MyISAM')
		{
			return $user->lang['FULLTEXT_MYSQL_NOT_MYISAM'];
		}

		$sql = 'SHOW VARIABLES
			LIKE \'ft\_%\'';
		$result = $db->sql_query($sql);

		$mysql_info = array();
		while ($row = $db->sql_fetchrow($result))
		{
			$mysql_info[$row['Variable_name']] = $row['Value'];
		}
		$db->sql_freeresult($result);

		set_config('fulltext_mysql_max_word_len', $mysql_info['ft_max_word_len']);
		set_config('fulltext_mysql_min_word_len', $mysql_info['ft_min_word_len']);

		return false;
	}

	/**
	* Splits keywords entered by a user into an array of words stored in $this->split_words
	* Stores the tidied search query in $this->search_query
	*
	* @param string &$keywords Contains the keyword as entered by the user
	* @param string $terms is either 'all' or 'any'
	* @return bool false if no valid keywords were found and otherwise true
	*/
	function split_keywords(&$keywords, $terms)
	{
		global $config;

		$this->get_ignore_words();
		$this->get_synonyms();

		if ($terms == 'all')
		{
			$match		= array('#\sand\s#iu', '#\sor\s#iu', '#\snot\s#iu', '#\+#', '#-#', '#\|#');
			$replace	= array(' +', ' |', ' -', ' +', ' -', ' |');

			$keywords = preg_replace($match, $replace, $keywords);
		}

		$match = array();
		// New lines, carriage returns
		$match[] = "#[\n\r]+#";
		// NCRs like &nbsp; etc.
		$match[] = '#(&amp;|&)[\#a-z0-9]+?;#i';

		// Filter out as above
		$keywords = preg_replace($match, ' ', trim($keywords));

		// Split words
		$split_keywords = preg_replace('#([^\w\'*])#', '$1$1', str_replace('\'\'', '\' \'', trim($keywords)));
		$matches = array();
		preg_match_all('#(?:[^\w*]|^)([+\-|]?(?:[\w*]+\'?)*[\w*])(?:[^\w*]|$)#', $split_keywords, $matches);
		$this->split_words = $matches[1];

		if (sizeof($this->ignore_words))
		{
			$this->common_words = array_intersect($this->split_words, $this->ignore_words);
			$this->split_words = array_diff($this->split_words, $this->ignore_words);
		}

		if (sizeof($this->replace_synonym))
		{
			$this->split_words = str_replace($this->replace_synonym, $this->match_synonym, $this->split_words);
		}

		foreach ($this->split_words as $i => $word)
		{
			$clean_word = preg_replace('#^[+\-|]#', '', $word);

			// check word length
			$clean_len = utf8_strlen(str_replace('*', '', $clean_word));
			if (($clean_len < $config['fulltext_mysql_min_word_len']) || ($clean_len > $config['fulltext_mysql_max_word_len']))
			{
				$this->common_words[] = $word;
				unset($this->split_words[$i]);
			}
		}

		$this->search_query = implode(' ', $this->split_words);

		if (sizeof($this->split_words))
		{
			$this->split_words = array_values($this->split_words);
			sort($this->split_words);
			return true;
		}
		return false;
	}

	/**
	* Turns text into an array of words
	*/
	function split_message($text)
	{
		global $config;

		$this->get_ignore_words();
		$this->get_synonyms();

		// Split words
		$text = preg_replace('#([^\w\'*])#', '$1$1', str_replace('\'\'', '\' \'', trim($text)));
		$matches = array();
		preg_match_all('#(?:[^\w*]|^)([+\-|]?(?:[\w*]+\'?)*[\w*])(?:[^\w*]|$)#', $text, $matches);
		$text = $matches[1];

		if (sizeof($this->ignore_words))
		{
			$text = array_diff($text, $this->ignore_words);
		}

		if (sizeof($this->replace_synonym))
		{
			$text = str_replace($this->replace_synonym, $this->match_synonym, $text);
		}

		// remove too short or too long words
		$text = array_values($text);
		for ($i = 0, $n = sizeof($text); $i < $n; $i++)
		{
			$text[$i] = trim($text[$i]);
			if (utf8_strlen($text[$i]) < $config['fulltext_mysql_min_word_len'] || utf8_strlen($text[$i]) > $config['fulltext_mysql_max_word_len'])
			{
				unset($text[$i]);
			}
		}

		return array_values($text);
	}

	/**
	* Performs a search on keywords depending on display specific params.
	*
	* @param array &$id_ary passed by reference, to be filled with ids for the page specified by $start and $per_page, should be ordered
	* @param int $start indicates the first index of the page
	* @param int $per_page number of ids each page is supposed to contain
	* @return total number of results
	*/
	function keyword_search($type, &$fields, &$terms, &$sort_by_sql, &$sort_key, &$sort_dir, &$sort_days, &$ex_fid_ary, &$m_approve_fid_ary, &$topic_id, &$author_ary, &$id_ary, $start, $per_page)
	{
		global $config, $db;

		// No keywords? No posts.
		if (!sizeof($this->split_words))
		{
			return false;
		}

		// generate a search_key from all the options to identify the results
		$search_key = md5(implode('#', array(
			implode(',', $this->split_words),
			$type,
			$fields,
			$terms,
			$sort_days,
			$sort_key,
			$topic_id,
			implode(',', $ex_fid_ary),
			implode(',', $m_approve_fid_ary),
			implode(',', $author_ary)
		)));

		// try reading the results from cache
		$result_count = 0;
		if ($this->obtain_ids($search_key, $result_count, $id_ary, $start, $per_page, $sort_dir) == SEARCH_RESULT_IN_CACHE)
		{
			return $result_count;
		}

		$id_ary = array();

		$join_topic = ($type == 'posts') ? false : true;

		// Build sql strings for sorting
		$sql_sort = $sort_by_sql[$sort_key] . (($sort_dir == 'a') ? ' ASC' : ' DESC');
		$sql_sort_table = $sql_sort_join = '';

		switch ($sql_sort[0])
		{
			case 'u':
				$sql_sort_table	= USERS_TABLE . ' u, ';
				$sql_sort_join	= ($type == 'posts') ? ' AND u.user_id = p.poster_id ' : ' AND u.user_id = t.topic_poster ';
			break;

			case 't':
				$join_topic = true;
			break;

			case 'f':
				$sql_sort_table	= FORUMS_TABLE . ' f, ';
				$sql_sort_join	= ' AND f.forum_id = p.forum_id ';
			break;
		}

		// Build some display specific sql strings
		switch ($fields)
		{
			case 'titleonly':
				$sql_match = 'p.post_subject';
				$sql_match_where = ' AND p.post_id = t.topic_first_post_id';
				$join_topic = true;
			break;

			case 'msgonly':
				$sql_match = 'p.post_text';
				$sql_match_where = '';
			break;

			case 'firstpost':
				$sql_match = 'p.post_subject, p.post_text';
				$sql_match_where = ' AND p.post_id = t.topic_first_post_id';
				$join_topic = true;
			break;

			default:
				$sql_match = 'p.post_subject, p.post_text';
				$sql_match_where = '';
			break;
		}

		if (!sizeof($m_approve_fid_ary))
		{
			$m_approve_fid_sql = ' AND p.post_approved = 1';
		}
		else if ($m_approve_fid_ary === array(-1))
		{
			$m_approve_fid_sql = '';
		}
		else
		{
			$m_approve_fid_sql = ' AND (p.post_approved = 1 OR ' . $db->sql_in_set('p.forum_id', $m_approve_fid_ary, true) . ')';
		}

		$sql_select			= (!$result_count) ? 'SQL_CALC_FOUND_ROWS ' : '';
		$sql_select			= ($type == 'posts') ? $sql_select . 'p.post_id' : 'DISTINCT ' . $sql_select . 't.topic_id';
		$sql_from			= ($join_topic) ? TOPICS_TABLE . ' t, ' : '';
		$field				= ($type == 'posts') ? 'post_id' : 'topic_id';
		$sql_author			= (sizeof($author_ary) == 1) ? ' = ' . $author_ary[0] : 'IN (' . implode(', ', $author_ary) . ')';

		$sql_where_options = $sql_sort_join;
		$sql_where_options .= ($topic_id) ? ' AND p.topic_id = ' . $topic_id : '';
		$sql_where_options .= ($join_topic) ? ' AND t.topic_id = p.topic_id' : '';
		$sql_where_options .= (sizeof($ex_fid_ary)) ? ' AND ' . $db->sql_in_set('p.forum_id', $ex_fid_ary, true) : '';
		$sql_where_options .= $m_approve_fid_sql;
		$sql_where_options .= (sizeof($author_ary)) ? ' AND p.poster_id ' . $sql_author : '';
		$sql_where_options .= ($sort_days) ? ' AND p.post_time >= ' . (time() - ($sort_days * 86400)) : '';
		$sql_where_options .= $sql_match_where;

		// split the words into words that have to be included or must not be included and optional words
		$words = $any_words = array();
		if ($terms == 'all')
		{
			foreach ($this->split_words as $id => $word)
			{
				if ((strpos($word, '+') === 0) || (strpos($word, '-') === 0))
				{
					$words[] = $word;
				}
				else if (strpos($word, '|') === 0)
				{
					$any_words[] = substr($word, 1);
				}
				else
				{
					$words[] = '+' . $word;
				}
			}
		}
		else
		{
			foreach ($this->split_words as $id => $word)
			{
				if ((strpos($word, '+') === 0) || (strpos($word, '-') === 0) || (strpos($word, '|') === 0))
				{
					$words[] = substr($word, 1);
				}
				else
				{
					$words[] = $word;
				}
			}
		}

		// Get the ids for the current result block
		$any_words = (sizeof($any_words)) ? ' +(' . implode(' ', $any_words) . ')' : '';

		$sql = "SELECT $sql_select
			FROM $sql_from$sql_sort_table" . POSTS_TABLE . " p
			WHERE MATCH ($sql_match) AGAINST ('" . $db->sql_escape(implode(' ', $words)) . $any_words . "' IN BOOLEAN MODE)
				$sql_where_options
			ORDER BY $sql_sort";
		$result = $db->sql_query_limit($sql, $config['search_block_size'], $start);

		while ($row = $db->sql_fetchrow($result))
		{
			$id_ary[] = $row[$field];
		}
		$db->sql_freeresult($result);

		$id_ary = array_unique($id_ary);

		if (!sizeof($id_ary))