<?php /** * Elgg core search. * * @package Elgg * @subpackage Core * @author Curverider Ltd <info@elgg.com>, The MITRE Corporation <http://www.mitre.org> * @link http://elgg.org/ */ /** * Initialise search helper functions. * */ function search_init() { global $CONFIG; require_once 'search_hooks.php'; // page handler for search actions and results register_page_handler('search','search_page_handler'); // register some default search hooks register_plugin_hook('search', 'object', 'search_objects_hook'); register_plugin_hook('search', 'user', 'search_users_hook'); // @todo pull this out into groups register_plugin_hook('search', 'group', 'search_groups_hook'); // tags and comments are a bit different. // register a search types and a hooks for them. register_plugin_hook('search_types', 'get_types', 'search_custom_types_tags_hook'); register_plugin_hook('search', 'tags', 'search_tags_hook'); register_plugin_hook('search_types', 'get_types', 'search_custom_types_comments_hook'); register_plugin_hook('search', 'comments', 'search_comments_hook'); // get server min and max allowed chars for ft searching $CONFIG->search_info = array(); // can't use get_data() here because some servers don't have these globals set, // which throws a db exception. $r = mysql_query('SELECT @@ft_min_word_len as min, @@ft_max_word_len as max'); if ($r && ($word_lens = mysql_fetch_assoc($r))) { $CONFIG->search_info['min_chars'] = $word_lens['min']; $CONFIG->search_info['max_chars'] = $word_lens['max']; } else { // uhhh these are good numbers. $CONFIG->search_info['min_chars'] = 4; $CONFIG->search_info['max_chars'] = 90; } // add in CSS for search elements elgg_extend_view('css', 'search/css'); } /** * Page handler for search * * @param array $page Page elements from pain page handler */ function search_page_handler($page) { global $CONFIG; // if there is no q set, we're being called from a legacy installation // it expects a search by tags. // actually it doesn't, but maybe it should. // maintain backward compatibility if(!get_input('q', get_input('tag', NULL))) { set_input('q', $page[0]); //set_input('search_type', 'tags'); } include_once('index.php'); } /** * Return a string with highlighted matched queries and relevant context * Determins context based upon occurance and distance of words with each other. * * @param string $haystack * @param string $query * @param int $min_match_context = 30 * @param int $max_length = 300 * @return string */ function search_get_highlighted_relevant_substrings($haystack, $query, $min_match_context = 30, $max_length = 300) { global $CONFIG; $haystack = strip_tags($haystack); $haystack_length = elgg_strlen($haystack); $haystack_lc = elgg_strtolower($haystack); $words = search_remove_ignored_words($query, 'array'); // if haystack < $max_length return the entire haystack w/formatting immediately if ($haystack_length <= $max_length) { $return = search_highlight_words($words, $haystack); return $return; } // get the starting positions and lengths for all matching words $starts = array(); $lengths = array(); foreach ($words as $word) { $word = elgg_strtolower($word); $count = elgg_substr_count($haystack_lc, $word); $word_len = elgg_strlen($word); // find the start positions for the words if ($count > 1) { $offset = 0; while (FALSE !== $pos = elgg_strpos($haystack_lc, $word, $offset)) { $start = ($pos - $min_match_context > 0) ? $pos - $min_match_context : 0; $starts[] = $start; $stop = $pos + $word_len + $min_match_context; $lengths[] = $stop - $start; $offset += $pos + $word_len; } } else { $pos = elgg_strpos($haystack_lc, $word); $start = ($pos - $min_match_context > 0) ? $pos - $min_match_context : 0; $starts[] = $start; $stop = $pos + $word_len + $min_match_context; $lengths[] = $stop - $start; } } $offsets = search_consolidate_substrings($starts, $lengths); // figure out if we can adjust the offsets and lengths // in order to return more context $total_length = array_sum($offsets); $add_length = 0; if ($total_length < $max_length) { $add_length = floor((($max_length - $total_length) / count($offsets)) / 2); $starts = array(); $lengths = array(); foreach ($offsets as $offset => $length) { $start = ($offset - $add_length > 0) ? $offset - $add_length : 0; $length = $length + $add_length; $starts[] = $start; $lengths[] = $length; } $offsets = search_consolidate_substrings($starts, $lengths); } // sort by order of string size descending (which is roughly // the proximity of matched terms) so we can keep the // substrings with terms closest together and discard // the others as needed to fit within $max_length. arsort($offsets); $return_strs = array(); $total_length = 0; foreach ($offsets as $start => $length) { $string = trim(elgg_substr($haystack, $start, $length)); // continue past if adding this substring exceeds max length if ($total_length + $length > $max_length) { continue; } $total_length += $length; $return_strs[$start] = $string; } // put the strings in order of occurence ksort($return_strs); // add ...s where needed $return = implode('...', $return_strs); if (!array_key_exists(0, $return_strs)) { $return = "...$return"; } // add to end of string if last substring doesn't hit the end. $starts = array_keys($return_strs); $last_pos = $starts[count($starts)-1]; if ($last_pos + elgg_strlen($return_strs[$last_pos]) < $haystack_length) { $return .= '...'; } $return = search_highlight_words($words, $return); return $return; } /** * Takes an array of offsets and lengths and consolidates any * overlapping entries, returning an array of new offsets and lengths * * Offsets and lengths are specified in separate arrays because of possible * index collisions with the offsets. * * @param array $offsets * @param array $lengths * @return array */ function search_consolidate_substrings($offsets, $lengths) { // sort offsets by occurence asort($offsets, SORT_NUMERIC); // reset the indexes maintaining association with the original offsets. $offsets = array_merge($offsets); $new_lengths = array(); foreach ($offsets as $i => $offset) { $new_lengths[] = $lengths[$i]; } $lengths = $new_lengths; $return = array(); $count = count($offsets); for ($i=0; $i<$count; $i++) { $offset = $offsets[$i]; $length = $lengths[$i]; $end_pos = $offset + $length; // find the next entry that doesn't overlap while(array_key_exists($i+1, $offsets) && $end_pos > $offsets[$i+1]) { $i++; if (!array_key_exists($i, $offsets)) { break; } $end_pos = $lengths[$i] + $offsets[$i]; } $length = $end_pos - $offset; // will never have a colliding offset, so can return as a single array $return[$offset] = $length; } return $return; } /** * Safely highlights the words in $words found in $string avoiding recursion * * @param array $words * @param string $string * @return string */ function search_highlight_words($words, $string) { $i = 1; $replace_html = array( 'strong' => rand(10000,99999), 'class' => rand(10000,99999), 'searchMatch' => rand(10000,99999), 'searchMatchColor' => rand(10000,99999) ); foreach ($words as $word) { $search = "/($word)/i"; // must replace with placeholders in case one of the search terms is // in the html string. // later, will replace the placeholders with the actual html. // Yeah this is hacky. I'm tired. $strong = $replace_html['strong']; $class = $replace_html['class']; $searchMatch = $replace_html['searchMatch']; $searchMatchColor = $replace_html['searchMatchColor']; $replace = "<$strong $class=\"$searchMatch $searchMatchColor{$i}\">$1</$strong>"; $string = preg_replace($search, $replace, $string); $i++; } foreach ($replace_html as $replace => $search) { $string = str_replace($search, $replace, $string); } return $string; } /** * Returns a query with stop and too short words removed. * (Unless the entire query is < ft_min_word_chars, in which case * it's taken literally.) * * @param array $query * @param str $format Return as an array or a string * @return mixed */ function search_remove_ignored_words($query, $format = 'array') { global $CONFIG; // don't worry about "s or boolean operators $query = str_replace(array('"', '-', '+', '~'), '', stripslashes(strip_tags($query))); $words = explode(' ', $query); $min_chars = $CONFIG->search_info['min_chars']; // if > ft_min_word we're not running in literal mode. if (elgg_strlen($query) >= $min_chars) { // clean out any words that are ignored by mysql foreach ($words as $i => $word) { if (elgg_strlen($word) < $min_chars) { unset ($words[$i]); } } } if ($format == 'string') { return implode(' ', $words); } return $words; } /** * Passes results, and original params to the view functions for * search type. * * @param array $results * @param array $params * @param string $view_type = listing, entity or listing * @return string */ function search_get_search_view($params, $view_type) { switch ($view_type) { case 'listing': case 'entity': case 'layout': break; default: return FALSE; } $view_order = array(); // check if there's a special search listing view for this type:subtype if (isset($params['type']) && $params['type'] && isset($params['subtype']) && $params['subtype']) { $view_order[] = "search/{$params['type']}/{$params['subtype']}/$view_type"; } // also check for the default type if (isset($params['type']) && $params['type']) { $view_order[] = "search/{$params['type']}/$view_type"; } // check search types if (isset($params['search_type']) && $params['search_type']) { $view_order[] = "search/{$params['search_type']}/$view_type"; } // finally default to a search listing default $view_order[] = "search/$view_type"; foreach ($view_order as $view) { if (elgg_view_exists($view)) { return $view; } } return FALSE; } /** * Returns a where clause for a search query. * * @param str $table Prefix for table to search on * @param array $fields Fields to match against * @param array $params Original search params * @return str */ function search_get_where_sql($table, $fields, $params, $use_fulltext = TRUE) { global $CONFIG; $query = $params['query']; // add the table prefix to the fields foreach ($fields as $i => $field) { if ($table) { $fields[$i] = "$table.$field"; } } // if we're not using full text, rewrite the query for bool mode. // exploiting a feature(ish) of bool mode where +-word is the same as -word if (!$use_fulltext) { $query = '+' . str_replace(' ', ' +', $query); } // if query is shorter than the min for fts words // it's likely a single acronym or similar // switch to literal mode if (elgg_strlen($query) < $CONFIG->search_info['min_chars']) { $likes = array(); $query = sanitise_string($query); foreach ($fields as $field) { $likes[] = "$field LIKE '%$query%'"; } $likes_str = implode(' OR ', $likes); $where = "($likes_str)"; } else { // if using advanced or paired "s, switch into boolean mode if (!$use_fulltext || (isset($params['advanced_search']) && $params['advanced_search']) || elgg_substr_count($query, '"') >= 2 ) { $options = 'IN BOOLEAN MODE'; } else { // natural language mode is default and this keyword isn't supported in < 5.1 //$options = 'IN NATURAL LANGUAGE MODE'; $options = ''; } // if short query, use query expansion. // @todo doesn't seem to be working well. if (elgg_strlen($query) < 5) { //$options .= ' WITH QUERY EXPANSION'; } $query = sanitise_string($query); $fields_str = implode(',', $fields); $where = "(MATCH ($fields_str) AGAINST ('$query' $options))"; } return $where; } /** * Returns ORDER BY sql for insertion into elgg_get_entities(). * * @param str $entities_table Prefix for entities table. * @param str $type_table Prefix for the type table. * @param str $sort ORDER BY part * @param str $order ASC or DESC * @return str */ function search_get_order_by_sql($entities_table, $type_table, $sort, $order) { $on = NULL; switch ($sort) { default: case 'relevance': // default is relevance descending. // acending relevancy is silly and complicated. $on = ''; break; case 'created': $on = "$entities_table.time_created"; break; case 'updated': $on = "$entities_table.time_updated"; break; case 'action_on': // @todo not supported yet in core $on = ''; break; case 'alpha': // @todo not support yet because both title // and name columns are used for this depending // on the entity, which we don't always know. >:O break; } $order = strtolower($order); if ($order != 'asc' && $order != 'desc') { $order = 'DESC'; } if ($on) { $order_by = "$on $order"; } else { $order_by = ''; } return $order_by; } /** Register init system event **/ register_elgg_event_handler('init','system','search_init');