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Pepperminty-Wiki/modules/feature-search.php

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<?php
register_module([
"name" => "Search",
"version" => "0.6.2",
"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;
/**
* @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");
$index = search::index($source);
var_dump($env->page);
var_dump($source);
var_dump($index);
});
/**
* @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::rebuild_invindex();
else
{
http_response_code(401);
exit(page_renderer::render_main("Error - Search index regenerator - $settings->sitename", "<p>Error: You aren't allowed to regenerate the search index. Try logging in as an admin, or setting the <code>secret</code> POST parameter to $settings->sitename's secret - which can be found in $settings->sitename's <code>peppermint.json</code> file.</p>"));
}
});
/**
* @api {get} ?action=idindex-show Show the id index
* @apiDescription Outputs the id index. Useful if you need to verify that it's working as expected. Output is a json object.
* @apiName SearchShowIdIndex
* @apiGroup Search
* @apiPermission Anonymous
*/
add_action("idindex-show", function() {
global $idindex;
header("content-type: application/json; charset=UTF-8");
exit(json_encode($idindex, JSON_PRETTY_PRINT));
});
/**
* @api {get} ?action=search&query={text}[&format={format}] Search the wiki for a given query string
* @apiName Search
* @apiGroup Search
* @apiPermission Anonymous
*
* @apiParam {string} query The query string to search for.
* @apiParam {string} format Optional. Valid values: html, json. In json mode an object is returned with page names as keys, values as search result information - sorted in ranking order.
*/
/*
* ███████ ███████ █████ ██████ ██████ ██ ██
* ██ ██ ██ ██ ██ ██ ██ ██ ██
* ███████ █████ ███████ ██████ ██ ███████
* ██ ██ ██ ██ ██ ██ ██ ██ ██
* ███████ ███████ ██ ██ ██ ██ ██████ ██ ██
*/
add_action("search", function() {
global $settings, $env, $pageindex, $paths;
// Create the inverted index if it doesn't exist.
// todo In the future perhaps a CLI for this would be good?
if(!file_exists($paths->searchindex))
search::rebuild_invindex(false);
if(!isset($_GET["query"]))
exit(page_renderer::render("No Search Terms - Error - $settings->sitename", "<p>You didn't specify any search terms. Try typing some into the box above.</p>"));
$search_start = microtime(true);
$invindex = search::load_invindex($paths->searchindex);
$results = search::query_invindex($_GET["query"], $invindex);
$resultCount = count($results);
foreach($results as &$result) {
$result["context"] = search::extract_context(
$_GET["query"],
file_get_contents($env->storage_prefix . $result["pagename"] . ".md")
);
}
if(!empty($_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));
}
$env->perfdata->search_time = round((microtime(true) - $search_start)*1000, 3);
$title = $_GET["query"] . " - Search results - $settings->sitename";
$content = "<section>\n";
$content .= "<h1>Search Results</h1>";
/// Search Box ///
$content .= "<form method='get' action=''>\n";
$content .= " <input type='search' id='search-box' name='query' placeholder='Type your query here and then press enter.' value='" . htmlentities($_GET["query"], ENT_HTML5 | ENT_QUOTES) . "' />\n";
$content .= " <input type='hidden' name='action' value='search' />\n";
$content .= "</form>";
$content .= "<p>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 $settings->sitename called <a href='?page=" . rawurlencode($query) . "'>$query</a>.";
}
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)
{
$content .= " You could try <a href='?action=login&returnto=" . rawurlencode($_SERVER["REQUEST_URI"]) . "'>logging in</a>.";
}
}
else
{
$content .= "can <a href='?action=edit&page=" . rawurlencode($query) . "'>create it</a>.";
}
}
$content .= "</p>";
if(module_exists("page-list")) {
$nterms = search::tokenize($query);
$nterms_regex = implode("|", array_map(function($nterm) {
return preg_quote(strtolower(trim($nterm)));
}, $nterms));
$all_tags = get_all_tags();
$matching_tags = [];
foreach($all_tags as $tag) {
if(preg_match("/$nterms_regex/i", trim($tag)) > 0)
$matching_tags[] = $tag;
}
if(count($matching_tags) > 0) {
$content .= "<p>Matching tags: <span class='tags'>";
foreach($matching_tags as $tag) {
$content .= "\t<a href='?action=list-tags&tag=" . rawurlencode($tag) ."' class='mini-tag'>" . htmlentities($tag) . "</a> \n";
}
$content .= "</span></p>";
}
}
$i = 0; // todo use $_GET["offset"] and $_GET["result-count"] or something
foreach($results as $result)
{
$link = "?page=" . rawurlencode($result["pagename"]);
$pagesource = file_get_contents($env->storage_prefix . $result["pagename"] . ".md");
//echo("Extracting context for result " . $result["pagename"] . ".\n");
$context = $result["context"];
if(mb_strlen($context) === 0)
$context = mb_substr($pagesource, 0, $settings->search_characters_context * 2);
//echo("'Generated search context for " . $result["pagename"] . ": $context'\n");
$context = search::highlight_context(
$_GET["query"],
preg_replace('/</u', '&lt;', $context)
);
/*if(strlen($context) == 0)
{
$context = search::strip_markup(file_get_contents("$env->page.md", null, null, null, $settings->search_characters_context * 2));
if($pageindex->{$env->page}->size > $settings->search_characters_context * 2)
$context .= "...";
}*/
$tag_list = "<span class='tags'>";
foreach($pageindex->{$result["pagename"]}->tags ?? [] as $tag) $tag_list .= "<a href='?action=list-tags&tag=" . rawurlencode($tag) . "' class='mini-tag'>$tag</a>";
$tag_list .= "</span>\n";
// Make redirect pages italics
if(!empty($pageindex->{$result["pagename"]}->redirect))
$result["pagename"] = "<em>{$result["pagename"]}</em>";
// We add 1 to $i here to convert it from an index to a result
// number as people expect it to start from 1
$content .= "<div class='search-result' data-result-number='" . ($i + 1) . "' data-rank='" . $result["rank"] . "'>\n";
$content .= " <h2><a href='$link'>" . $result["pagename"] . "</a> <span class='search-result-badges'>$tag_list</span></h2>\n";
$content .= " <p class='search-context'>$context</p>\n";
$content .= "</div>\n";
$i++;
}
$content .= "</section>\n";
header("content-type: text/html; charset=UTF-8");
exit(page_renderer::render($title, $content));
//header("content-type: text/plain");
//var_dump($results);
});
/*
* ██████ ██ ██ ███████ ██████ ██ ██
* ██ ██ ██ ██ ██ ██ ██ ██ ██
* ██ ██ ██ ██ █████ ██████ ████ █████
* ██ ▄▄ ██ ██ ██ ██ ██ ██ ██
* ██████ ██████ ███████ ██ ██ ██
* ▀▀
* ███████ ███████ █████ ██████ ██████ ██ ██ ██ ███ ██ ██████ ███████ ██ ██
* ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ████ ██ ██ ██ ██ ██ ██
* ███████ █████ ███████ ██████ ██ ███████ ██ ██ ██ ██ ██ ██ █████ ███
* ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██
* ███████ ███████ ██ ██ ██ ██ ██████ ██ ██ ██ ██ ████ ██████ ███████ ██ ██
*/
/**
* @api {get} ?action=query-searchindex&query={text} Inspect the internals of the search results for a query
* @apiName Search
* @apiGroup Search
* @apiPermission Anonymous
*
* @apiParam {string} query The query string to search for.
*/
add_action("query-searchindex", function() {
global $env, $paths;
if(empty($_GET["query"])) {
http_response_code(400);
header("content-type: text/plain");
exit("Error: No query specified. Specify it with the 'query' GET parameter.");
}
$env->perfdata->searchindex_decode_start = microtime(true);
$searchIndex = search::load_invindex($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);
$env->perfdata->searchindex_query_time = (microtime(true) - $env->perfdata->searchindex_query_start) * 1000;
header("content-type: application/json");
$result = new stdClass();
$result->time_format = "ms";
$result->decode_time = $env->perfdata->searchindex_decode_time;
$result->query_time = $env->perfdata->searchindex_query_time;
$result->total_time = $result->decode_time + $result->query_time;
$result->search_results = $searchResults;
exit(json_encode($result, JSON_PRETTY_PRINT));
});
/*
* ██████ ██████ ███████ ███ ██ ███████ ███████ █████ ██████ ██████ ██ ██
* ██ ██ ██ ██ ██ ████ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██
* ██ ██ ██████ █████ ██ ██ ██ ███████ █████ ███████ ██████ ██ ███████
* ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██ ██
* ██████ ██ ███████ ██ ████ ███████ ███████ ██ ██ ██ ██ ██████ ██ ██
*/
/**
* @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('<?xml version="1.0" encoding="UTF-8"?' . '>' . // hack The build system strips it otherwise O.o I should really fix that.
"\n<OpenSearchDescription xmlns=\"http://a9.com/-/spec/opensearch/1.1/\">
<ShortName>Search $settings->sitename</ShortName>
<Description>Search $settings->sitename, which is powered by Pepperminty Wiki.</Description>
<Tags>$settings->sitename Wiki</Tags>
<Image type=\"image/png\">$settings->favicon</Image>
<Attribution>Search content available under the license linked to at the bottom of the search results page.</Attribution>
<Developer>Starbeamrainbowlabs (https://github.com/sbrl/Pepperminty-Wiki/graphs/contributors)</Developer>
<InputEncoding>UTF-8</InputEncoding>
<OutputEncoding>UTF-8</OutputEncoding>
<Url type=\"text/html\" method=\"get\" template=\"$siteRoot?action=view&amp;search-redirect=yes&amp;page={searchTerms}&amp;offset={startIndex?}&amp;count={count}\" />
<Url type=\"application/x-suggestions+json\" template=\"$siteRoot?action=suggest-pages&amp;query={searchTerms}&amp;type=opensearch\" />
</OpenSearchDescription>");
});
/**
* @api {get} ?action=suggest-pages[&type={type}] Get page name suggestions for a query
* @apiName OpenSearchDescription
* @apiGroup Search
* @apiPermission Anonymous
*
* @apiParam {string} text The search query string to get search suggestions for.
* @apiParam {string} type The type of result to return. Default value: json. Available values: json, opensearch
*/
add_action("suggest-pages", function() {
global $settings, $pageindex;
if($settings->dynamic_page_suggestion_count === 0)
{
header("content-type: application/json");
header("content-length: 3");
exit("[]\n");
}
if(empty($_GET["query"])) {
http_response_code(400);
header("content-type: text/plain");
exit("Error: You didn't specify the 'query' GET parameter.");
}
$type = $_GET["type"] ?? "json";
if(!in_array($type, ["json", "opensearch"])) {
http_response_code(406);
exit("Error: The type '$type' is not one of the supported output types. Available values: json, opensearch. Default: json");
}
// Rank each page name
$results = [];
foreach($pageindex as $pageName => $entry) {
$results[] = [
"pagename" => $pageName,
// Costs: Insert: 1, Replace: 8, Delete: 6
"distance" => levenshtein(mb_strtolower($_GET["query"]), mb_strtolower($pageName), 1, 8, 6)
];
}
// Sort the page names by distance from the original query
usort($results, function($a, $b) {
if($a["distance"] == $b["distance"])
return strcmp($a["pagename"], $b["pagename"]);
return $a["distance"] < $b["distance"] ? -1 : 1;
});
// Send the results to the user
$suggestions = array_slice($results, 0, $settings->dynamic_page_suggestion_count);
switch($type)
{
case "json":
header("content-type: application/json");
exit(json_encode($suggestions));
case "opensearch":
$opensearch_output = [
$_GET["query"],
array_map(function($suggestion) { return $suggestion["pagename"]; }, $suggestions)
];
header("content-type: application/x-suggestions+json");
exit(json_encode($opensearch_output));
}
});
if($settings->dynamic_page_suggestion_count > 0)
{
page_renderer::AddJSSnippet('/// Dynamic page suggestion system
// Micro snippet 8 - Promisified GET (fetched 20th Nov 2016)
function get(u){return new Promise(function(r,t,a){a=new XMLHttpRequest();a.onload=function(b,c){b=a.status;c=a.response;if(b>199&&b<300){r(c)}else{t(c)}};a.open("GET",u,true);a.send(null)})}
window.addEventListener("load", function(event) {
var searchBox = document.querySelector("input[type=search]");
searchBox.dataset.lastValue = "";
searchBox.addEventListener("keyup", function(event) {
// Make sure that we don\'t keep sending requests to the server if nothing has changed
if(searchBox.dataset.lastValue == event.target.value)
return;
searchBox.dataset.lastValue = event.target.value;
// Fetch the suggestions from the server
get("?action=suggest-pages&query=" + encodeURIComponent(event.target.value)).then(function(response) {
var suggestions = JSON.parse(response),
dataList = document.getElementById("allpages");
// If the server sent no suggestions, then we shouldn\'t replace the contents of the datalist
if(suggestions.length == 0)
return;
console.info(`Fetched suggestions for ${event.target.value}:`, suggestions.map(s => s.pagename));
// Remove all the existing suggestions
while(dataList.firstChild) {
dataList.removeChild(dataList.firstChild);
}
// Add the new suggestions to the datalist
var optionsFrag = document.createDocumentFragment();
suggestions.forEach(function(suggestion) {
var suggestionElement = document.createElement("option");
suggestionElement.value = suggestion.pagename;
suggestionElement.dataset.distance = suggestion.distance;
optionsFrag.appendChild(suggestionElement);
});
dataList.appendChild(optionsFrag);
});
});
});
');
}
}
]);
/**
* Holds a collection to methods to manipulate various types of search index.
*/
class search
{
/**
* Words that we should exclude from the inverted index
*/
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", "cannot", "cant", "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", "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"
];
/**
* Converts a source string into an index of search terms that can be
* merged into an inverted index.
* @param string $source The source string to index.
* @return array An index represents the specified string.
*/
public static function index($source)
{
$source = html_entity_decode($source, ENT_QUOTES);
$source_length = mb_strlen($source);
$index = [];
$terms = self::tokenize($source);
$i = 0;
foreach($terms as $term)
{
$nterm = $term;
// Skip over stop words (see https://en.wikipedia.org/wiki/Stop_words)
if(in_array($nterm, self::$stop_words)) continue;
if(!isset($index[$nterm]))
{
$index[$nterm] = [ "freq" => 0, "offsets" => [] ];
}
$index[$nterm]["freq"]++;
$index[$nterm]["offsets"][] = $i;
$i++;
}
return $index;
}
/**
* Converts a source string into a series of raw tokens.
* @param string $source The source string to process.
* @return array An array of raw tokens extracted from the specified source string.
*/
public static function tokenize($source)
{
$source = Normalizer::normalize(strtolower($source), Normalizer::FORM_C);
$source = preg_replace('/[\[\]\|\{\}\/]/u', " ", $source);
return preg_split("/((^\p{P}+)|(\p{P}*\s+\p{P}*)|(\p{P}+$))|\|/u", $source, -1, PREG_SPLIT_NO_EMPTY);
}
/**
* Removes (most) markdown markup from the specified string.
* Stripped strings are not suitable for indexing!
* @param string $source The source string to process.
* @return string The stripped string.
*/
public static function strip_markup($source)
{
return preg_replace('/([\"*_\[\]]| - |`)/u', "", $source);
}
/**
* Rebuilds the master inverted index and clears the page id index.
* @param boolean $output Whether to send progress information to the user's browser.
*/
public static function rebuild_invindex($output = true)
{
global $pageindex, $env, $paths, $settings;
if($output) {
header("content-type: text/event-stream");
ob_end_flush();
}
// Clear the id index out
ids::clear();
// Reindex each page in turn
$invindex = [];
$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;
}
$pagesource = Normalizer::normalize(file_get_contents($page_filename), Normalizer::FORM_C);
$index = self::index($pagesource);
$pageid = ids::getid($pagename);
self::merge_into_invindex($invindex, $pageid, $index);
if($output) {
echo("data: [" . ($i + 1) . " / $max] Added $pagename (id #$pageid) to the new search index.\n\n");
flush();
}
$i++;
}
if($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");
}
self::save_invindex($paths->searchindex, $invindex);
}
/**
* Sorts an index alphabetically. Will also sort an inverted index.
* This allows us to do a binary search instead of a regular
* sequential search.
* @param array $index The index to sort.
*/
public static function sort_index(&$index)
{
ksort($index, SORT_NATURAL);
}
/**
* 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 $removed An array to be filled with the nterms of all the removed entries.
*/
public static function compare_indexes($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 world is new
$newindex[$nterm] !== $oldindex[$nterm]) // If this word has changed
$changed[$nterm] = $newindex[$nterm];
}
}
/**
* Reads in and parses an inverted index.
* @param string $invindex_filename The path tp the inverted index to parse.
* @todo Remove this function and make everything streamable
*/
public static function load_invindex($invindex_filename) {
$invindex = json_decode(file_get_contents($invindex_filename), true);
return $invindex;
}
/**
* Reads in and parses an inverted index, measuring the time it takes to do so.
* @param string $invindex_filename The path to the file inverted index to parse.
*/
public static function measure_invindex_load_time($invindex_filename) {
global $env;
$searchindex_decode_start = microtime(true);
search::load_invindex($invindex_filename);
$env->perfdata->searchindex_decode_time = round((microtime(true) - $searchindex_decode_start)*1000, 3);
}
/**
* Merge an index into an inverted index.
* @param array $invindex The inverted index to merge into.
* @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 $removals An array of index entries to remove from the inverted index. Useful for applying changes to an inverted index instead of deleting and remerging an entire page's index.
*/
public static function merge_into_invindex(&$invindex, $pageid, &$index, &$removals = [])
{
// Remove all the subentries that were removed since last time
foreach($removals as $nterm)
{
unset($invindex[$nterm][$pageid]);
}
// Merge all the new / changed index entries into the inverted index
foreach($index as $nterm => $newentry)
{
// If the nterm isn't in the inverted index, then create a space for it
if(!isset($invindex[$nterm])) $invindex[$nterm] = [];
$invindex[$nterm][$pageid] = $newentry;
// Sort the page entries for this word by frequency
uasort($invindex[$nterm], function($a, $b) {
if($a["freq"] == $b["freq"]) return 0;
return ($a["freq"] < $b["freq"]) ? +1 : -1;
});
}
// Sort the inverted index by rank
uasort($invindex, function($a, $b) {
$ac = count($a); $bc = count($b);
if($ac == $bc) return 0;
return ($ac < $bc) ? +1 : -1;
});
}
/**
* Deletes the given pageid from the given pageindex.
* @param inverted_index &$invindex The inverted index.
* @param number $pageid The pageid to remove.
*/
public static function delete_entry(&$invindex, $pageid)
{
$str_pageid = (string)$pageid;
foreach($invindex as $nterm => &$entry)
{
if(isset($entry[$pageid]))
unset($entry[$pageid]);
if(isset($entry[$str_pageid]))
unset($entry[$str_pageid]);
if(count($entry) === 0)
unset($invindex[$nterm]);
}
}
/**
* Saves the given inverted index back to disk.
* @param string $filename The path to the file to save the inverted index to.
* @param array $invindex The inverted index to save.
*/
public static function save_invindex($filename, &$invindex)
{
file_put_contents($filename, json_encode($invindex));
}
/**
* 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)
{
global $settings, $pageindex;
$query_terms = self::tokenize($query);
$matching_pages = [];
// 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];
// 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;
// Only search the inverted index if it actually exists there
if(isset($invindex[$qterm]))
{
// Loop over each page in the inverted index entry
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] = $page_entry;
}
}
// Loop over the pageindex and search the titles / tags
foreach ($pageindex as $pagename => $pagedata)
{
// Get the current page's id
$pageid = ids::getid($pagename);
// Consider matches in the page title
if(stripos($pagename, $qterm) !== false)
{
// We found the qterm in the title
if(!isset($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"] += count(mb_stripos_all($pagename, $qterm)) * strlen($qterm);
}
// Consider matches in the page's tags
if(isset($pagedata->tags) and // If this page has tags
stripos(implode(" ", $pagedata->tags), $qterm) !== false) // And we found the qterm in the tags
{
if(!isset($matching_pages[$pageid]))
$matching_pages[$pageid] = [ "nterms" => [] ];
// 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"] += count(mb_stripos_all(implode(" ", $pagedata->tags), $qterm)) * strlen($qterm);
}
}
}
foreach($matching_pages as $pageid => &$pagedata)
{
$pagedata["pagename"] = ids::getpagename($pageid);
$pagedata["rank"] = 0;
$pageOffsets = [];
// Loop over each search term found on this page
foreach($pagedata["nterms"] as $pterm => $entry)
{
// Add the number of occurrences of this search term to the ranking
// Multiply it by the length of the word
$pagedata["rank"] += $entry["freq"] * strlen($pterm);
// Add the offsets to a listof all offsets on this page
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"]))
$pagedata["rank"] += $pagedata["title-matches"] * $settings->search_title_matches_weighting;
if(isset($pagedata["tag-matches"]))
$pagedata["rank"] += $pagedata["tag-matches"] * $settings->search_tags_matches_weighting;
// todo remove items if the rank is below a threshold
}
// todo sort by rank here
uasort($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 $query The search queary to generate the context for.
* @param string $source The page source to extract the context from.
* @return string The generated context string.
*/
public static function extract_context($query, $source)
{
global $settings;
$nterms = self::tokenize($query);
$matches = [];
// Loop over each nterm and find it in the source
foreach($nterms as $nterm)
{
if(in_array($nterm, static::$stop_words))
continue;
$all_offsets = mb_stripos_all($source, $nterm);
// Skip over adding matches if there aren't any
if($all_offsets === false)
continue;
foreach($all_offsets as $offset)
{
$matches[] = [ $nterm, $offset ];
}
}
// Sort the matches by offset
usort($matches, function($a, $b) {
if($a[1] == $b[1]) return 0;
return ($a[1] > $b[1]) ? +1 : -1;
});
$sourceLength = mb_strlen($source);
$contexts = [];
$basepos = 0;
$matches_count = count($matches);
while($basepos < $matches_count)
{
// Store the next match along - all others will be relative to that one
$group = [$matches[$basepos]];
// Start scanning at the next one along - we always store the first match
$scanpos = $basepos + 1;
$distance = 0;
while(true)
{
// Break out if we reach the end
if($scanpos >= $matches_count) break;
// Find the distance between the current one and the last one
$distance = $matches[$scanpos][1] - $matches[$scanpos - 1][1];
// Store it if the distance is below the threshold
if($distance < $settings->search_characters_context)
$group[] = $matches[$scanpos];
else
break;
$scanpos++;
}
$context_start = $group[0][1] - $settings->search_characters_context;
$context_end = $group[count($group) - 1][1] + $settings->search_characters_context;
if($context_start < 0) $context_start = 0;
if($context_end > $sourceLength) $context_end = $sourceLength;
//echo("Got context. Start: $context_start, End: $context_end\n");
//echo("Group:"); var_dump($group);
$context = substr($source, $context_start, $context_end - $context_start);
// Strip the markdown from the context - it's most likely going to
// be broken anyway.
//$context = self::strip_markup($context);
// Escape special characters to protect against attacks
$context = htmlentities($context);
$contexts[] = $context;
$basepos = $scanpos + 1;
}
return implode(" ... ", $contexts);
}
/**
* 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)
{
$qterms = self::tokenize($query);
foreach($qterms as $qterm)
{
if(in_array($qterm, static::$stop_words))
continue;
// From http://stackoverflow.com/a/2483859/1460422
$context = preg_replace("/" . preg_replace('/\\//u', "\/", preg_quote($qterm)) . "/iu", "<strong class='search-term-highlight'>$0</strong>", $context);
}
return $context;
}
}
?>
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