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Start refactoring query_invindex & rename it to invindex_query

....but of course it's not finished yet. We're doing well, but there are 
a few thorny issues to go.

Mainly: We need to seriously optimise ids::getpagename(), 'cause we'll 
need it a *lot* when we get to implementing the size, before, and after 
colon : directives.
This commit is contained in:
Starbeamrainbowlabs 2019-08-18 21:25:48 +01:00
parent 0807cce256
commit b93dd3d9cc
Signed by: sbrl
GPG key ID: 1BE5172E637709C2

View file

@ -136,7 +136,7 @@ register_module([
$env->perfdata->invindex_decode_time = round((microtime(true) - $time_start)*1000, 3);
$time_start = microtime(true);
$results = search::query_invindex($_GET["query"], $invindex);
$results = search::invindex_query($_GET["query"], $invindex);
$resultCount = count($results);
$env->perfdata->invindex_query_time = round((microtime(true) - $time_start)*1000, 3);
@ -306,7 +306,7 @@ register_module([
$searchIndex = search::invindex_load($paths->searchindex);
$env->perfdata->searchindex_decode_time = (microtime(true) - $env->perfdata->searchindex_decode_start) * 1000;
$env->perfdata->searchindex_query_start = microtime(true);
$searchResults = search::query_invindex($_GET["query"], $searchIndex);
$searchResults = search::invindex_query($_GET["query"], $searchIndex);
$env->perfdata->searchindex_query_time = (microtime(true) - $env->perfdata->searchindex_query_start) * 1000;
header("content-type: application/json");
@ -882,91 +882,295 @@ class search
$this->invindex->set("|termlist|", json_encode($termlist));
}
/*
* ███████ ████████ █████ ███████
* ██ ██ ██ ██ ██
* ███████ ██ ███████ ███████
* ██ ██ ██ ██ ██
* ███████ ██ ██ ██ ███████
*/
/**
* Splits a *transliterated* query string into tokens.
* Actually based on my earlier explode_adv https://starbeamrainbowlabs.com/blog/article.php?article=posts/081-PHP-String-Splitting.html
* @param string $query The queyr string to split.
*/
private function stas_split($query) {
$chars = str_split($query);
$terms = [];
$next_term = "";
$toggle_state = false; // true = now inside, false = now outside
foreach($chars as $char)
{
if($char == '"') {
// Invert the toggle block state
$toggle_state = !$toggle_state;
}
// If this char is whitespace *and* we're outside a toggle block, then it's a token
if(ctype_space($char) && !$toggle_state) {
// If the string is empty, then don't bother
if(empty($next_term)) continue;
$terms[] = $next_term;
$next_term = "";
}
// If it's not whitespace, or it is whitespace and we're inside a toggle block....
else if(!ctype_space($char) || ($toggle_state && ctype_space($char)))
$next_term .= $char; // ...then add the char to the next part
}
if(strlen($next_term) > 0)
$terms[] = $next_term;
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[] $tokens The array of query tokens to parse.
*/
private function stas_parse($tokens) {
/* 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] == "-") {
$result["exclude"][] = substr($tokens[$i], 1);
continue;
}
// Look for weighted terms
if($tokens[$i][0] == "+") {
$result["terms"][] = [
"term" => substr($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":
$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) ? 0 : -1,
"location" => "all"
];
}
return $result;
}
/**
* Searches the given inverted index for the specified search terms.
* @param string $query The search query.
* @param array $invindex The inverted index to search.
* @return array An array of matching pages.
*/
public static function query_invindex($query, &$invindex)
public static function invindex_query($query)
{
global $settings, $pageindex;
/** Normalises input characters for searching & indexing */
static $literator; if($literator == null) $literator = Transliterator::createFromRules(':: Any-Latin; :: Latin-ASCII; :: NFD; :: [:Nonspacing Mark:] Remove; :: Lower(); :: NFC;', Transliterator::FORWARD);
$query_terms = self::tokenize($query);
$query_stas = $this->stas_parse(
$this->stas_split($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
];
// Loop over each term in the query and find the matching page entries
$count = count($query_terms);
for($i = 0; $i < $count; $i++)
{
$qterm = $query_terms[$i];
// Query the inverted index
foreach($query_stas as $term_def) {
if($term_def["weight"] == -1)
continue; // Skip stop words
// Stop words aren't worth the bother - make sure we don't search
// the title or the tags for them
if(in_array($qterm, self::$stop_words))
continue;
if(!in_array($term_def["location"], ["all", "inbody"]))
continue; // Skip terms we shouldn't search the page body for
// Only search the inverted index if it actually exists there
if(isset($invindex[$qterm])) {
// Loop over each page in the inverted index entry
reset($invindex[$qterm]); // Reset array/object pointer
foreach($invindex[$qterm] as $pageid => $page_entry) {
// Create an entry in the matching pages array if it doesn't exist
if(!isset($matching_pages[$pageid]))
$matching_pages[$pageid] = [ "nterms" => [] ];
$matching_pages[$pageid]["nterms"][$qterm] = $page_entry;
if(!$this->$invindex->has($term_def["term"]))
continue; // Skip if it's not in the index
// For each page that contains this term.....
$term_pageids = json_decode($this->invindex->get($term_def["term"]));
foreach($term_pageids as $pageid) {
// Check to see if it contains any words we should exclude
$skip = false;
foreach($query_stas["exclude"] as $exlc_term) {
if($this->invindex->has("$excl_term|$pageid")) {
$skip = true;
break;
}
}
if($skip) continue;
// Get the list of offsets
$page_offsets = json_decode($this->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
);
$matching_pages[$pageid]["nterms"][$term_def["term"]] = count($page_offsets) * $term_def["weight"];
}
}
// Query page titles & tags
foreach($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", "intitle", "intags"]))
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 => $pagedata)
{
foreach ($pageindex as $pagename => $pagedata) {
// Setup a variable to hold the current page's id
$pageid = false; // Only fill this out if we find a match
$pageid = null; // Cache the page id
$lit_title = $literator->transliterate($pagename);
$lit_tags = $literator->transliterate(implode(" ", $pagedata->tags));
// 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
// 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
$title_matches = mb_stripos_all($literator->transliterate($pagename), $qterm);
$title_matches_count = $title_matches !== false ? count($title_matches) : 0;
if($title_matches_count > 0)
{
$pageid = ids::getid($pagename); // Fill out the page id
// We found the qterm in the title
if(!isset($matching_pages[$pageid]))
$matching_pages[$pageid] = [ "nterms" => [] ];
// Set up a counter for page title matches if it doesn't exist already
if(!isset($matching_pages[$pageid]["title-matches"]))
$matching_pages[$pageid]["title-matches"] = 0;
$matching_pages[$pageid]["title-matches"] += $title_matches_count * strlen($qterm);
if(in_array($term_def["location"], ["all", "intitle"])) {
// 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 * $term_def["weight"];
}
}
if(!in_array($term_def["location"], ["all", "intags"]))
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($literator->transliterate(implode(" ", $pagedata->tags)), $qterm) : false;
$tag_matches = isset($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 == false) // Fill out the page id if it hasn't been already
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] = [ "nterms" => [] ];
$matching_pages[$pageid] = $match_template; // Assign by copy
// Set up a counter for tag match if there isn't one already
if(!isset($matching_pages[$pageid]["tag-matches"]))
$matching_pages[$pageid]["tag-matches"] = 0;
$matching_pages[$pageid]["tag-matches"] += $tag_matches_count * strlen($qterm);
$matching_pages[$pageid]["rank_tags"] += $tag_matches_count * $term_def["weight"];
}
}
}
// TODO: Implement the rest of STAS here
// TODO: We got up to here; finish refactoring invindex_query
reset($matching_pages);
foreach($matching_pages as $pageid => &$pagedata)
{
@ -987,29 +1191,6 @@ class search
foreach($entry["offsets"] as $offset)
$pageOffsets[] = $offset;
}
/*
// Sort the list of offsets
$pageOffsets = array_unique($pageOffsets);
sort($pageOffsets);
var_dump($pageOffsets);
// Calcualate the clump distances via a variable moving window size
$pageOffsetsCount = count($pageOffsets);
$clumpDistanceWindow = min($count, $pageOffsetsCount); // a.k.a. count($query_terms) - see above
$clumpDistances = [];
for($i = 0; $i < $pageOffsetsCount - $clumpDistanceWindow; $i++)
$clumpDistances[] = $pageOffsets[$i] - $pageOffsets[$i + $clumpDistanceWindow];
// Sort the new list of clump distances
sort($clumpDistances);
// Calcualate a measure of how clumped the offsets are
$tightClumpLimit = floor((count($clumpDistances) - 1) / 0.25);
$tightClumpsMeasure = $clumpDistances[$tightClumpLimit] - $clumpDistances[0];
$clumpsRange = $clumpDistances[count($clumpDistances) - 1] - $clumpDistances[0];
$clumpiness = $tightClumpsMeasure / $clumpsRange;
echo("{$pagedata["pagename"]} - $clumpiness");
*/
// Consider matches in the title / tags
if(isset($pagedata["title-matches"]))