"Search", "version" => "0.11", "author" => "Starbeamrainbowlabs", "description" => "Adds proper search functionality to Pepperminty Wiki using an inverted index to provide a full text search engine. If pages don't show up, then you might have hit a stop word. If not, try requesting the `invindex-rebuild` action to rebuild the inverted index from scratch.", "id" => "feature-search", "code" => function() { global $settings, $paths; /** * @api {get} ?action=index&page={pageName} Get an index of words for a given page * @apiName SearchIndex * @apiGroup Search * @apiPermission Anonymous * @apiDescription For debugging purposes. Be warned - the format could change at any time! * * @apiParam {string} page The page to generate a word index page. */ /* * ██ ███ ██ ██████ ███████ ██ ██ * ██ ████ ██ ██ ██ ██ ██ ██ * ██ ██ ██ ██ ██ ██ █████ ███ * ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██ ██ ████ ██████ ███████ ██ ██ */ add_action("index", function() { global $settings, $env; $breakable_chars = "\r\n\t .,\\/!\"£$%^&*[]()+`_~#"; header("content-type: text/plain"); $source = file_get_contents("$env->storage_prefix$env->page.md"); $index = search::index_generate($source); echo("Page name: $env->page\n"); echo("--------------- Source ---------------\n"); echo($source); echo("\n"); echo("--------------------------------------\n\n"); echo("---------------- Index ---------------\n"); foreach($index as $term => $entry) { echo("$term: {$entry["freq"]} matches | " . implode(", ", $entry["offsets"]) . "\n"); } echo("--------------------------------------\n"); }); /** * @api {get} ?action=invindex-rebuild Rebuild the inverted search index from scratch * @apiDescription Causes the inverted search index to be completely rebuilt from scratch. Can take a while for large wikis! * @apiName SearchInvindexRebuild * @apiGroup Search * @apiPermission Admin * * @apiParam {string} secret Optional. Specify the secret from peppermint.json here in order to rebuild the search index without logging in. */ /* * ██ ███ ██ ██ ██ ██ ███ ██ ██████ ███████ ██ ██ * ██ ████ ██ ██ ██ ██ ████ ██ ██ ██ ██ ██ ██ * ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ █████ ███ █████ * ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██ ██ ████ ████ ██ ██ ████ ██████ ███████ ██ ██ * * ██████ ███████ ██████ ██ ██ ██ ██ ██████ * ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██████ █████ ██████ ██ ██ ██ ██ ██ ██ * ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██ ██ ███████ ██████ ██████ ██ ███████ ██████ */ add_action("invindex-rebuild", function() { global $env, $settings; if($env->is_admin || ( !empty($_POST["secret"]) && $_POST["secret"] === $settings->secret ) ) search::invindex_rebuild(); else { http_response_code(401); exit(page_renderer::render_main("Error - Search index regenerator - $settings->sitename", "
Error: You aren't allowed to regenerate the search index. Try logging in as an admin, or setting the secret
POST parameter to $settings->sitename's secret - which can be found in $settings->sitename's peppermint.json
file.
You didn't specify any search terms. Try typing some into the box above.
")); $search_start = microtime(true); $time_start = microtime(true); search::invindex_load($paths->searchindex); $env->perfdata->invindex_decode_time = round((microtime(true) - $time_start)*1000, 3); $time_start = microtime(true); $results = search::invindex_query($_GET["query"]); $resultCount = count($results); $env->perfdata->invindex_query_time = round((microtime(true) - $time_start)*1000, 3); header("x-invindex-load-time: {$env->perfdata->invindex_decode_time}ms"); header("x-invindex-query-time: {$env->perfdata->invindex_query_time}ms"); $start = microtime(true); foreach($results as &$result) { $result["context"] = search::extract_context( $result["pagename"], $_GET["query"], file_get_contents($env->storage_prefix . $result["pagename"] . ".md") ); } $env->perfdata->context_generation_time = round((microtime(true) - $start)*1000, 3); header("x-context-generation-time: {$env->perfdata->context_generation_time}ms"); $env->perfdata->search_time = round((microtime(true) - $search_start)*1000, 3); header("x-search-time: {$env->perfdata->search_time}ms"); if(!empty($_GET["format"]) && $_GET["format"] == "json") { header("content-type: application/json"); $json_results = new stdClass(); foreach($results as $result) $json_results->{$result["pagename"]} = $result; exit(json_encode($json_results)); } $title = $_GET["query"] . " - Search results - $settings->sitename"; $content = "Found $resultCount " . ($resultCount === 1 ? "result" : "results") . " in " . $env->perfdata->search_time . "ms. ";
$query = $_GET["query"];
if(isset($pageindex->$query)) {
$content .= "There's a page on $settings->sitename called $query.";
}
else
{
$content .= "There isn't a page called $query on $settings->sitename, but you ";
if((!$settings->anonedits && !$env->is_logged_in) || !$settings->editing) {
$content .= "do not have permission to create it.";
if(!$env->is_logged_in) {
$content .= " You could try logging in.";
}
}
else {
$content .= "can create it.";
}
}
$content .= "
Pssst! Power users can make use of $settings->sitename's advanced query syntax. Learn about it here!
$context
\n"; $content .= "$settings->sitename understood your query to mean the following:
$result")); }); /* * ██████ ██████ ███████ ███ ██ ███████ ███████ █████ ██████ ██████ ██ ██ * ██ ██ ██ ██ ██ ████ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██ ██ ██████ █████ ██ ██ ██ ███████ █████ ███████ ██████ ██ ███████ * ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ * ██████ ██ ███████ ██ ████ ███████ ███████ ██ ██ ██ ██ ██████ ██ ██ */ /** * @api {get} ?action=opensearch-description Get the opensearch description file * @apiName OpenSearchDescription * @apiGroup Search * @apiPermission Anonymous */ add_action("opensearch-description", function () { global $settings; $siteRoot = full_url() . "/index.php"; if(!isset($_GET["debug"])) header("content-type: application/opensearchdescription+xml"); else header("content-type: text/plain"); exit('' . // hack The build system strips it otherwise O.o I should really fix that. "\n
$settings->sitename has an integrated full-text search engine, allowing you to search all of the pages on $settings->sitename and their content. To use it, simply enter your query into the page name box and press enter. If a page isn't found with the exact name of your query terms, a search will be performed instead.
Additionally, advanced users can take advantage of some extra query syntax that $settings->sitename supports, which is inspired by popular search engines:
Example | Meaning |
---|---|
cat -dog | Search for pages containing \"cat\", but not \"dog\". This syntax does not make sense on it's own - other words must be present for it to take effect. |
+glass marble | Double the weighting of the word \"glass\". |
intitle:rocket | Search only page titles for \"rocket\". |
intags:bill | Search only tags for \"bill\". |
inbody:satellite | Search only the page body for \"satellite\". |
More query syntax will be added in the future, so keep an eye on the latest releases of Pepperminty Wiki to stay up-to-date (Atom / RSS feed available here).
"); } ]); /* ███████ ████████ ██████ ██████ █████ ██████ ███████ ██████ ██████ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ███████ ██ ██ ██ ██████ ███████ ██ ███ █████ ██████ ██ ██ ███ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ███████ ██ ██████ ██ ██ ██ ██ ██████ ███████ ██████ ██████ ██ ██ */ /** * Represents a key-value data store. */ class StorageBox { const MODE_JSON = 0; const MODE_ARR_SIMPLE = 1; /** * The SQLite database connection. * @var \PDO */ private $db; /** * A cache of values. * @var object[] */ private $cache = []; /** * A cache of prepared SQL statements. * @var \PDOStatement[] */ private $query_cache = []; /** * Initialises a new store connection. * @param string $filename The filename that the store is located in. */ function __construct(string $filename) { $firstrun = !file_exists($filename); $this->db = new \PDO("sqlite:" . path_resolve($filename, __DIR__)); // HACK: This might not work on some systems, because it depends on the current working directory $this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); if($firstrun) { $this->query("CREATE TABLE store (key TEXT UNIQUE NOT NULL, value TEXT)"); } } /** * Makes a query against the database. * @param string $sql The (potentially parametised) query to make. * @param array $variables Optional. The variables to substitute into the SQL query. * @return \PDOStatement The result of the query, as a PDOStatement. */ private function query(string $sql, array $variables = []) { // Add to the query cache if it doesn't exist if(!isset($this->query_cache[$sql])) $this->query_cache[$sql] = $this->db->prepare($sql); $this->query_cache[$sql]->execute($variables); return $this->query_cache[$sql]; // fetchColumn(), fetchAll(), etc. are defined on the statement, not the return value of execute() } /** * Determines if the given key exists in the store or not. * @param string $key The key to test. * @return bool Whether the key exists in the store or not. */ public function has(string $key) : bool { if(isset($this->cache[$key])) return true; return $this->query( "SELECT COUNT(key) FROM store WHERE key = :key;", [ "key" => $key ] )->fetchColumn() > 0; } /** * Gets a value from the store. * @param string $key The key value is stored under. * @return mixed The stored value. */ public function get(string $key) { // If it's not in the cache, insert it if(!isset($this->cache[$key])) { $this->cache[$key] = [ "modified" => false, "value" => json_decode($this->query( "SELECT value FROM store WHERE key = :key;", [ "key" => $key ] )->fetchColumn()) ]; } return $this->cache[$key]["value"]; } public function get_arr_simple(string $key, string $delimiter = "|") { // If it's not in the cache, insert it if(!isset($this->cache[$key])) { $this->cache[$key] = [ "modified" => false, "value" => explode($delimiter, $this->query( "SELECT value FROM store WHERE key = :key;", [ "key" => $key ] )->fetchColumn()) ]; } return $this->cache[$key]["value"]; } /** * Sets a value in the data store. * Note that this does NOT save changes to disk until you close the connection! * @param string $key The key to set the value of. * @param mixed $value The value to store. */ public function set(string $key, $value) : void { if(!isset($this->cache[$key])) $this->cache[$key] = []; $this->cache[$key]["value"] = $value; $this->cache[$key]["modified"] = true; $this->cache[$key]["mode"] = self::MODE_JSON; } public function set_arr_simple(string $key, $value, string $delimiter = "|") : void { if(!isset($this->cache[$key])) $this->cache[$key] = []; $this->cache[$key]["value"] = $value; $this->cache[$key]["modified"] = true; $this->cache[$key]["delimiter"] = $delimiter; $this->cache[$key]["mode"] = self::MODE_ARR_SIMPLE; } /** * Deletes an item from the data store. * @param string $key The key of the item to delete. * @return bool Whether it was really deleted or not. Note that if it doesn't exist, then it can't be deleted. */ public function delete(string $key) : bool { // Remove it from the cache if(isset($this->cache[$key])) unset($this->cache[$key]); // Remove it from disk // TODO: Queue this action for the transaction later return $this->query( "DELETE FROM store WHERE key = :key;", [ "key" => $key ] )->rowCount() > 0; } /** * Empties the store. */ public function clear() : void { // Empty the cache; $this->cache = []; // Empty the disk $this->query("DELETE FROM store;"); } /** * Syncs changes to disk and closes the PDO connection. */ public function close() : void { $this->db->beginTransaction(); foreach($this->cache as $key => $value_data) { // If it wasn't modified, there's no point in saving it, is there? if(!$value_data["modified"]) continue; $this->query( "INSERT OR REPLACE INTO store(key, value) VALUES(:key, :value)", [ "key" => $key, "value" => $value_data["mode"] == self::MODE_ARR_SIMPLE ? implode($value_data["delimiter"], $value_data["value"]) : json_encode($value_data["value"]) ] ); } $this->db->commit(); $this->db = null; } } /* ███████ ███████ █████ ██████ ██████ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ███████ █████ ███████ ██████ ██ ███████ ██ ██ ██ ██ ██ ██ ██ ██ ██ ███████ ███████ ██ ██ ██ ██ ██████ ██ ██ */ /** * Holds a collection to methods to manipulate various types of search index. * @package search */ class search { /** * Words that we should exclude from the inverted index. * @source http://xpo6.com/list-of-english-stop-words/ * @var string[] */ public static $stop_words = [ "a", "about", "above", "above", "across", "after", "afterwards", "again", "against", "all", "almost", "alone", "along", "already", "also", "although", "always", "am", "among", "amongst", "amoungst", "amount", "an", "and", "another", "any", "anyhow", "anyone", "anything", "anyway", "anywhere", "are", "around", "as", "at", "back", "be", "became", "because", "become", "becomes", "becoming", "been", "before", "beforehand", "behind", "being", "below", "beside", "besides", "between", "beyond", "bill", "both", "bottom", "but", "by", "call", "can", "can't", "cannot", "co", "con", "could", "couldnt", "cry", "de", "describe", "detail", "do", "done", "down", "due", "during", "each", "eg", "eight", "either", "eleven", "else", "elsewhere", "empty", "enough", "etc", "even", "ever", "every", "everyone", "everything", "everywhere", "except", "few", "fill", "find", "fire", "first", "five", "for", "former", "formerly", "found", "four", "from", "front", "full", "further", "get", "give", "go", "had", "has", "hasnt", "have", "he", "hence", "her", "here", "hereafter", "hereby", "herein", "hereupon", "hers", "herself", "him", "himself", "his", "how", "however", "ie", "if", "in", "inc", "indeed", "interest", "into", "is", "it", "its", "it's", "itself", "keep", "last", "latter", "latterly", "least", "less", "ltd", "made", "many", "may", "me", "meanwhile", "might", "mine", "more", "moreover", "most", "mostly", "move", "much", "must", "my", "myself", "name", "namely", "neither", "never", "nevertheless", "next", "nine", "no", "none", "nor", "not", "nothing", "now", "nowhere", "of", "off", "often", "on", "once", "one", "only", "onto", "or", "other", "others", "otherwise", "our", "ours", "ourselves", "out", "over", "own", "part", "per", "perhaps", "please", "put", "rather", "re", "same", "see", "seem", "seemed", "seeming", "seems", "serious", "several", "she", "should", "show", "side", "since", "sincere", "six", "sixty", "so", "some", "somehow", "someone", "something", "sometime", "sometimes", "somewhere", "still", "such", "system", "take", "ten", "than", "that", "the", "their", "them", "themselves", "then", "thence", "there", "thereafter", "thereby", "therefore", "therein", "thereupon", "these", "they", "thickv", "thin", "third", "this", "those", "though", "three", "through", "throughout", "thru", "thus", "to", "together", "too", "top", "toward", "towards", "twelve", "twenty", "two", "un", "under", "until", "up", "upon", "us", "very", "via", "was", "we", "well", "were", "what", "whatever", "when", "whence", "whenever", "where", "whereafter", "whereas", "whereby", "wherein", "whereupon", "wherever", "whether", "which", "while", "whither", "who", "whoever", "whole", "whom", "whose", "why", "will", "with", "within", "without", "would", "yet", "you", "your", "yours", "yourself", "yourselves" ]; /** * The StorageBox that contains the inverted index. * @var StorageBox */ private static $invindex = null; /** * The transliterator that can be used to transliterate strings. * Transliterated strings are more suitable for use with the search index. * Note that this is no longer wrapped in a function as of v0.21 for * performance reasons. * @var Transliterator */ public static $literator = null; /** * Initialises the search system. * Do not call this function! It is called automatically. */ public static function init() { self::$literator = Transliterator::createFromRules(':: Any-Latin; :: Latin-ASCII; :: NFD; :: [:Nonspacing Mark:] Remove; :: Lower(); :: NFC;', Transliterator::FORWARD); } /** * Converts a source string into an index of search terms that can be * merged into an inverted index. * Automatically transliterates the source string. * @param string $source The source string to index. * @return array An index represents the specified string. */ public static function index_generate(string $source) : array { // We don't need to normalise or transliterate here because self::tokenize() does this for us $source = html_entity_decode($source, ENT_QUOTES); $source_length = mb_strlen($source); $index = []; $terms = self::tokenize($source, true); foreach($terms as $term) { // Skip over stop words (see https://en.wikipedia.org/wiki/Stop_words) if(in_array($term[0], self::$stop_words)) continue; if(!isset($index[$term[0]])) $index[$term[0]] = [ "freq" => 0, "offsets" => [] ]; $index[$term[0]]["freq"]++; $index[$term[0]]["offsets"][] = $term[1]; } return $index; } /** * Converts a source string into a series of raw tokens. * @param string $source The source string to process. * @param bool $capture_offsets Whether to capture & return the character offsets of the tokens detected. If true, then each token returned will be an array in the form [ token, char_offset ]. * @return array An array of raw tokens extracted from the specified source string. */ public static function tokenize(string $source, bool $capture_offsets = false) : array { $flags = PREG_SPLIT_NO_EMPTY; // Don't return empty items if($capture_offsets) $flags |= PREG_SPLIT_OFFSET_CAPTURE; // We don't need to normalise here because the transliterator handles $source = self::$literator->transliterate($source); $source = preg_replace('/[\[\]\|\{\}\/]/u', " ", $source); return preg_split("/((^\p{P}+)|(\p{P}*\s+\p{P}*)|(\p{P}+$))|\|/u", $source, -1, $flags); } /** * Removes (most) markdown markup from the specified string. * Stripped strings are not suitable for indexing! * @param string $source The source string to process. * @return string The stripped string. */ public static function strip_markup(string $source) : string { return preg_replace('/([\"*_\[\]]| - |`)/u', "", $source); } /** * Rebuilds the master inverted index and clears the page id index. * @param bool $output Whether to send progress information to the user's browser. */ public static function invindex_rebuild(bool $output = true) : void { global $pageindex, $env, $paths, $settings; if($output) { header("content-type: text/event-stream"); ob_end_flush(); } // Clear the id index out ids::clear(); // Clear the existing inverted index out if(self::$invindex == null) self::invindex_load($paths->searchindex); self::$invindex->clear(); self::$invindex->set("|termlist|", []); // Reindex each page in turn $i = 0; $max = count(get_object_vars($pageindex)); $missing_files = 0; foreach($pageindex as $pagename => $pagedetails) { $page_filename = $env->storage_prefix . $pagedetails->filename; if(!file_exists($page_filename)) { echo("data: [" . ($i + 1) . " / $max] Error: Can't find $page_filename\n"); flush(); $i++; $missing_files++; continue; } // We do not transliterate or normalise here because the indexer will take care of this for us $index = self::index_generate(file_get_contents($page_filename)); $pageid = ids::getid($pagename); self::invindex_merge($pageid, $index); if($output) { echo("data: [" . ($i + 1) . " / $max] Added $pagename (id #$pageid) to the new search index.\n\n"); flush(); } $i++; } echo("data: Syncing to disk....\n\n"); self::invindex_close(); if($output) { echo("data: Search index rebuilding complete.\n\n"); echo("data: Couldn't find $missing_files pages on disk. If $settings->sitename couldn't find some pages on disk, then you might need to manually correct $settings->sitename's page index (stored in pageindex.json).\n\n"); echo("data: Done! Saving new search index to '$paths->searchindex'.\n\n"); } // No need to save, it's an SQLite DB backend } /** * Sorts an index alphabetically. * This allows us to do a binary search instead of a regular * sequential search. * @param array $index The index to sort. */ public static function index_sort(&$index) { $sorter = new Collator(""); uksort($index, function($a, $b) use($sorter) : int { return $sorter->compare($a, $b); }); } /** * Compares two *regular* indexes to find the differences between them. * @param array $oldindex The old index. * @param array $newindex The new index. * @param array $changed An array to be filled with the nterms of all the changed entries. * @param array $removed An array to be filled with the nterms of all the removed entries. */ public static function index_compare($oldindex, $newindex, &$changed, &$removed) { foreach($oldindex as $nterm => $entry) { if(!isset($newindex[$nterm])) $removed[] = $nterm; } foreach($newindex as $nterm => $entry) { if(!isset($oldindex[$nterm]) or // If this word is new $newindex[$nterm] !== $oldindex[$nterm]) // If this word has changed $changed[$nterm] = $newindex[$nterm]; } } /** * Loads a connection to an inverted index. * @param string $invindex_filename The path to the inverted index to load. * @todo Remove this function and make everything streamable */ public static function invindex_load(string $invindex_filename) { global $env, $paths; $start_time = microtime(true); self::$invindex = new StorageBox($invindex_filename); $env->perfdata->searchindex_load_time = round((microtime(true) - $start_time)*1000, 3); } /** * Closes the currently open inverted index. */ public static function invindex_close() { global $env; $start_time = microtime(true); self::$invindex->close(); $env->perfdata->searchindex_close_time = round((microtime(true) - $start_time)*1000, 3); } /** * Merge an index into an inverted index. * @param int $pageid The id of the page to assign to the index that's being merged. * @param array $index The regular index to merge. * @param array $removals An array of index entries to remove from the inverted index. Useful for applying changes to an inverted index instead of deleting and remerging an entire page's index. */ public static function invindex_merge($pageid, &$index, &$removals = []) : void { if(self::$invindex == null) throw new Exception("Error: Can't merge into an inverted index that isn't loaded."); if(!self::$invindex->has("|termlist|")) self::$invindex->set("|termlist|", []); $termlist = self::$invindex->get("|termlist|"); // Remove all the subentries that were removed since last time foreach($removals as $nterm) { // Delete the offsets self::$invindex->delete("$nterm|$pageid"); // Delete the item from the list of pageids containing this term $nterm_pageids = self::$invindex->get_arr_simple($nterm); array_splice($nterm_pageids, array_search($pageid, $nterm_pageids), 1); if(empty($nterm_pageids)) { // No need to keep the pageid list if there's nothing in it self::$invindex->delete($nterm); // Update the termlist if we're deleting the term completely $termlist_loc = array_search($nterm, $termlist); if($termlist_loc !== false) array_splice($termlist, $termlist_loc, 1); } else self::$invindex->set_arr_simple($nterm, $nterm_pageids); } // Merge all the new / changed index entries into the inverted index foreach($index as $nterm => $newentry) { // if(!is_string($nterm)) $nterm = strval($nterm); if(!self::$invindex->has($nterm)) { self::$invindex->set_arr_simple($nterm, []); $termlist[] = $nterm; } // Update the nterm pageid list $nterm_pageids = self::$invindex->get_arr_simple($nterm); if(array_search($pageid, $nterm_pageids) === false) { $nterm_pageids[] = $pageid; self::$invindex->set_arr_simple($nterm, $nterm_pageids); } // Store the offset list self::$invindex->set("$nterm|$pageid", $newentry); } self::$invindex->set("|termlist|", $termlist); } /** * Deletes the given pageid from the given pageindex. * @param int $pageid The pageid to remove. */ public static function invindex_delete(int $pageid) { $termlist = self::$invindex->get("|termlist|"); foreach($termlist as $nterm) { $nterm_pageids = self::$invindex->get_arr_simple($nterm); $nterm_loc = array_search($pageid, $nterm_pageids); // If this nterm doesn't appear in the list, we're not interested if($nterm_loc === false) continue; // Delete it from the ntemr list array_splice($nterm_pageids, $nterm_loc, 1); // Delete the offset list self::$invindex->delete("$nterm|$pageid"); // If this term doesn't appear in any other documents, delete it if(count($nterm_pageids) === 0) { self::$invindex->delete($nterm); array_splice($termlist, array_search($nterm, $termlist), 1); } else // Save the document id list back, since it still contains other pageids self::$invindex->set_arr_simple($nterm, $nterm_pageids); } // Save the termlist back to the store self::$invindex->set("|termlist|", $termlist); } /* * ███████ ████████ █████ ███████ * ██ ██ ██ ██ ██ * ███████ ██ ███████ ███████ * ██ ██ ██ ██ ██ * ███████ ██ ██ ██ ███████ */ /** * Splits a query string into tokens. Does not require that the input string be transliterated. * Was based on my earlier explode_adv: https://starbeamrainbowlabs.com/blog/article.php?article=posts/081-PHP-String-Splitting.html * Now improved to be strtok-based, since it's much faster. * Example I used when writing this: https://www.php.net/manual/en/function.strtok.php#94463 * @param string $query The query string to split. */ public function stas_split($query) { $query = self::$literator->transliterate($query); $terms = []; $next_token = strtok($query, " \r\n\t"); while(true) { if(strpos($next_token, '"') !== false) $next_token .= " " . strtok('"') . '"'; if(strpos($next_token, "'") !== false) $next_token .= " " . strtok("'") . "'"; $terms[] = $next_token; $next_token = strtok(" \r\n\t"); if($next_token === false) break; } return $terms; } /** * Parses an array of query tokens into an associative array of search directives. * Supported syntax derived from these sources: * https://help.duckduckgo.com/duckduckgo-help-pages/results/syntax/ * https://docs.microsoft.com/en-us/windows/win32/lwef/-search-2x-wds-aqsreference * @param string[] $tokens The array of query tokens to parse. */ public function stas_parse($tokens) { global $settings; /* Supported Syntax * * * -term exclude a term * +term double the weighting of a term * terms !dest terms redirect entire query (minus the !bang) to interwiki with registered shortcut dest * prefix:term apply prefix operator to term */ // var_dump($tokens); $result = [ "terms" => [], "exclude" => [], "interwiki" => null ]; // foreach($operators as $op) // $result[$op] = []; $count = count($tokens); for($i = count($tokens) - 1; $i >= 0; $i--) { // Look for excludes if($tokens[$i][0] == "-") { if(in_array(substr($tokens[$i], 1), self::$stop_words)) { $result["tokens"][] = [ "term" => substr($tokens[$i], 1), "weight" => -1, "location" => "all" ]; } else $result["exclude"][] = substr($tokens[$i], 1); continue; } // Look for weighted terms if($tokens[$i][0] == "+") { if(in_array(substr($tokens[$i], 1), self::$stop_words)) { $result["tokens"] = [ "term" => substr($tokens[$i], 1), "weight" => -1, "location" => "all" ]; } else { $result["terms"][] = [ "term" => substr($tokens[$i], 1), "weight" => 2, "location" => "all" ]; } continue; } // Look for interwiki searches if($tokens[$i][0] == "!" || substr($tokens[$i], -1) == "!") { // You can only go to 1 interwiki destination at once, so we replace any previous finding with this one $result["interwiki"] = trim($tokens[$i], "!"); } // Look for colon directives in the form directive:term // Also supports prefix:"quoted term with spaces", quotes stripped automatically /*** Example directives *** (. = implemented, * = not implemented) . intitle search only page titles for term . intags search only tags for term . inbody search page body only for term * before search only pages that were last modified before term * after search only pages that were last modified after term * size search only pages that match the size spec term (e.g. 1k+ -> more than 1k bytes, 2k- -> less than 2k bytes, >5k -> more than 5k bytes, <10k -> less than 10k bytes) **************************/ if(strpos($tokens[$i], ":") !== false) { $parts = explode(":", $tokens[$i], 2); if(!isset($result[$parts[0]])) $result[$parts[0]] = []; switch($parts[0]) { case "intitle": // BUG: What if a normal word is found in a title? $result["terms"][] = [ "term" => $parts[1], "weight" => $settings->search_title_matches_weighting * mb_strlen($parts[1]), "location" => "title" ]; break; case "intags": $result["terms"][] = [ "term" => $parts[1], "weight" => $settings->search_tags_matches_weighting * mb_strlen($parts[1]), "location" => "tags" ]; break; case "inbody": $result["terms"][] = [ "term" => $parts[1], "weight" => 1, "location" => "body" ]; break; default: $result[$parts[0]][] = trim($parts[1], '"'); break; } continue; } // Doesn't appear to be particularly special *shrugs* // Set the weight to -1 if it's a stop word $result["terms"][] = [ "term" => $tokens[$i], "weight" => in_array($tokens[$i], self::$stop_words) ? -1 : 1, "location" => "all" ]; } return $result; } /** * Searches the given inverted index for the specified search terms. * @param string $query The search query. * @return array An array of matching pages. */ public static function invindex_query($query) { global $settings, $pageindex; $query_stas = self::stas_parse( self::stas_split(self::$literator->transliterate($query)) ); /* Sub-array format: * [ * nterms : [ nterm => frequency, nterm => frequency, .... ], * offsets_body : int[], * matches_title : int, * matches_tags : int * ] */ $matching_pages = []; $match_template = [ "nterms" => [], "offsets_body" => [], "rank_title" => 0, "rank_tags" => 0 ]; // Query the inverted index foreach($query_stas["terms"] as $term_def) { if($term_def["weight"] == -1) continue; // Skip stop words if(!in_array($term_def["location"], ["all", "inbody"])) continue; // Skip terms we shouldn't search the page body for if(!self::$invindex->has($term_def["term"])) continue; // Skip if it's not in the index // For each page that contains this term..... $term_pageids = self::$invindex->get_arr_simple($term_def["term"]); foreach($term_pageids as $pageid) { // Check to see if it contains any words we should exclude $skip = false; foreach($query_stas["exclude"] as $excl_term) { if(self::$invindex->has("$excl_term|$pageid")) { $skip = true; break; } } if($skip) continue; // Get the list of offsets $page_offsets = self::$invindex->get("{$term_def["term"]}|$pageid"); if(!isset($matching_pages[$pageid])) $matching_pages[$pageid] = $match_template; // Arrays are assigned by copy in php // Add it to the appropriate $matching_pages entry, not forgetting to apply the weighting $matching_pages[$pageid]["offsets_body"] = array_merge( $matching_pages[$pageid]["offsets_body"], $page_offsets->offsets ); $matching_pages[$pageid]["nterms"][$term_def["term"]] = $page_offsets->freq * $term_def["weight"]; } } // Query page titles & tags foreach($query_stas["terms"] as $term_def) { // No need to skip stop words here, since we're doing a normal // sequential search anyway if(!in_array($term_def["location"], ["all", "title", "tags"])) continue; // Skip terms we shouldn't search the page body for // Loop over the pageindex and search the titles / tags reset($pageindex); // Reset array/object pointer foreach($pageindex as $pagename => $pagedata) { // Setup a variable to hold the current page's id $pageid = null; // Cache the page id $lit_title = self::$literator->transliterate($pagename); $lit_tags = isset($pagedata->tags) ? self::$literator->transliterate(implode(" ", $pagedata->tags)) : null; // Make sure that the title & tags don't contain a term we should exclude $skip = false; foreach($query_stas["exclude"] as $excl_term) { if(mb_strpos($lit_title, $excl_term) !== false) { $skip = true; // Delete it from the candidate matches (it might be present in the tags / title but not the body) if(isset($matching_pages[$excl_term])) unset($matching_pages[$excl_term]); break; } } if($skip) continue; // Consider matches in the page title if(in_array($term_def["location"], ["all", "title"])) { // FUTURE: We may be able to optimise this further by using preg_match_all + preg_quote instead of mb_stripos_all. Experimentation / benchmarking is required to figure out which one is faster $title_matches = mb_stripos_all($lit_title, $term_def["term"]); $title_matches_count = $title_matches !== false ? count($title_matches) : 0; if($title_matches_count > 0) { $pageid = ids::getid($pagename); // Fetch the page id // We found the qterm in the title if(!isset($matching_pages[$pageid])) $matching_pages[$pageid] = $match_template; // Assign by copy $matching_pages[$pageid]["rank_title"] += $title_matches_count * $term_def["weight"]; } } // If this page doesn't have any tags, skip it if($lit_tags == null) continue; if(!in_array($term_def["location"], ["all", "tags"])) continue; // If we shouldn't search the tags, no point in continuing // Consider matches in the page's tags $tag_matches = isset($pagedata->tags) ? mb_stripos_all($lit_tags, $term_def["term"]) : false; $tag_matches_count = $tag_matches !== false ? count($tag_matches) : 0; if($tag_matches_count > 0) {// And we found the qterm in the tags if($pageid === null) // Fill out the page id if it hasn't been already $pageid = ids::getid($pagename); if(!isset($matching_pages[$pageid])) $matching_pages[$pageid] = $match_template; // Assign by copy $matching_pages[$pageid]["rank_tags"] += $tag_matches_count * $term_def["weight"]; } } } // TODO: Implement the rest of STAS here reset($matching_pages); foreach($matching_pages as $pageid => &$pagedata) { $pagedata["pagename"] = ids::getpagename($pageid); $pagedata["rank"] = 0; $pageOffsets = []; // Loop over each search term found on this page reset($pagedata["nterms"]); foreach($pagedata["nterms"] as $pterm => $frequency) { // Add the number of occurrences of this search term to the ranking // Multiply it by the length of the word $pagedata["rank"] += $frequency * strlen($pterm); } // Consider matches in the title / tags $pagedata["rank"] += $pagedata["rank_title"] + $pagedata["rank_tags"]; // TODO: Consider implementing kernel density estimation here. // https://en.wikipedia.org/wiki/Kernel_density_estimation // We want it to have more of an effect the more words that are present in the query. Maybe a logarithmic function would be worth investigating here? // TODO: Remove items if the computed rank is below a threshold } uasort($matching_pages, function($a, $b) { if($a["rank"] == $b["rank"]) return 0; return ($a["rank"] < $b["rank"]) ? +1 : -1; }); return $matching_pages; } /** * Extracts a context string (in HTML) given a search query that could be displayed * in a list of search results. * @param string $pagename The name of the paget that this source belongs to. Used when consulting the inverted index. * @param string $query The search queary to generate the context for. * @param string $source The page source to extract the context from. * @return string The generated context string. */ public static function extract_context($pagename, $query, $source) { global $settings; $pageid = ids::getid($pagename); $nterms = self::stas_parse(self::stas_split($query))["terms"]; // Query the inverted index for offsets $matches = []; foreach($nterms as $nterm) { // Skip if the page isn't found in the inverted index for this word if(!self::$invindex->has("{$nterm["term"]}|$pageid")) continue; $nterm_offsets = self::$invindex->get("{$nterm["term"]}|$pageid")->offsets; foreach($nterm_offsets as $next_offset) $matches[] = [ $nterm["term"], $next_offset ]; } // Sort the matches by offset usort($matches, function($a, $b) { if($a[1] == $b[1]) return 0; return ($a[1] > $b[1]) ? +1 : -1; }); $sourceLength = mb_strlen($source); $contexts = []; $matches_count = count($matches); $total_context_length = 0; for($i = 0; $i < $matches_count; $i++) { $next_context = [ "from" => max(0, $matches[$i][1] - $settings->search_characters_context), "to" => min($sourceLength, $matches[$i][1] + mb_strlen($matches[$i][0]) + $settings->search_characters_context) ]; if(end($contexts) !== false && end($contexts)["to"] > $next_context["from"]) { // This next context overlaps with the previous one // Extend the last one instead of adding a new one // The array pointer is pointing at the last element now because we called end() above // Update the total context length counter appropriately $total_context_length += $next_context["to"] - $contexts[key($contexts)]["to"]; $contexts[key($contexts)]["to"] = $next_context["to"]; } else { // No overlap here! Business as usual. $contexts[] = $next_context; // Update the total context length counter as normal $total_context_length += $next_context["to"] - $next_context["from"]; } end($contexts); $last_context = &$contexts[key($contexts)]; if($total_context_length > $settings->search_characters_context_total) { // We've reached the limit on the number of characters this context should contain. Trim off the context to fit and break out $last_context["to"] -= $total_context_length - $settings->search_characters_context_total; break; } } $contexts_text = []; foreach($contexts as $context) { $contexts_text[] = substr($source, $context["from"], $context["to"] - $context["from"]); } // BUG: Make sure that a snippet is centred on the word in question if we have to cut it short $result = implode(" … ", $contexts_text); end($contexts); // If there's at least one item in the list and were not at the very end of the page, add an extra ellipsis if(isset($contexts[0]) && $contexts[key($contexts)]["to"] < $sourceLength) $result .= "… "; // Prepend an ellipsis if the context doesn't start at the beginning of a page if(isset($contexts[0]) && $contexts[0]["from"] > 0) $result = " …$result"; return $result; } /** * Highlights the keywords of a context string. * @param string $query The query to use when highlighting. * @param string $context The context string to highlight. * @return string The highlighted (HTML) string. */ public static function highlight_context($query, $context) { $qterms = self::stas_parse(self::stas_split($query))["terms"]; foreach($qterms as $qterm) { // Stop words are marked by STAS if($qterm["weight"] == -1) continue; // From http://stackoverflow.com/a/2483859/1460422 $context = preg_replace("/" . preg_replace('/\\//u', "\/", preg_quote($qterm["term"])) . "/iu", "$0", $context); } return $context; } } // Run the init function search::init(); ?>