Pepperminty-Wiki/modules/feature-search.php

529 lines
19 KiB
PHP

<?php
register_module([
"name" => "Search",
"version" => "0.2.1",
"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() {
/*
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*/
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);
});
/*
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*/
add_action("invindex-rebuild", function() {
search::rebuild_invindex();
});
/*
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*/
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();
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);
$search_end = microtime(true) - $search_start;
$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='" . $_GET["query"] . "' />\n";
$content .= " <input type='hidden' name='action' value='search' />\n";
$content .= "</form>";
$query = $_GET["query"];
if(isset($pageindex->$query))
{
$content .= "<p>There's a page on $settings->sitename called <a href='?page=" . rawurlencode($query) . "'>$query</a>.</p>";
}
else
{
$content .= "<p>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>.</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");
$context = search::extract_context($_GET["query"], $pagesource);
$context = search::highlight_context($_GET["query"], $context);
/*if(strlen($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 .= "...";
}*/
// 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></h2>\n";
$content .= " <p>$context</p>\n";
$content .= "</div>\n";
$i++;
}
$content .= "</section>\n";
exit(page_renderer::render($title, $content));
//header("content-type: text/plain");
//var_dump($results);
});
}
]);
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", "fifteen", "fify", "fill", "find",
"fire", "first", "five", "for", "former", "formerly", "forty", "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", "hundred", "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"
];
public static function index($source)
{
$source = html_entity_decode($source, ENT_QUOTES);
$source_length = strlen($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 $index;
}
public static function tokenize($source)
{
$source = strtolower($source);
return preg_split("/((^\p{P}+)|(\p{P}*\s+\p{P}*)|(\p{P}+$))|\|/", $source, -1, PREG_SPLIT_NO_EMPTY);
}
public static function strip_markup($source)
{
return str_replace([ "[", "]", "\"", "*", "_", " - ", "`" ], "", $source);
}
public static function rebuild_invindex()
{
global $pageindex, $env, $paths;
$invindex = [];
foreach($pageindex as $pagename => $pagedetails)
{
$pagesource = file_get_contents("$env->storage_prefix$pagename.md");
$index = self::index($pagesource);
self::merge_into_invindex($invindex, ids::getid($pagename), $index);
}
self::save_invindex($paths->searchindex, $invindex);
}
/*
* @summary Sorts an index alphabetically. Will also sort an inverted index.
* This allows us to do a binary search instead of a regular
* sequential search.
*/
public static function sort_index(&$index)
{
ksort($index, SORT_NATURAL);
}
/*
* @summary Compares two *regular* indexes to find the differences between them.
*
* @param {array} $indexa - The old index.
* @param {array} $indexb - 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];
}
}
/*
* @summary Reads in and parses an inverted index.
*/
// 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 $invindex;
}
/*
* @summary Merge an index into an inverted index.
*/
public static function merge_into_invindex(&$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[$nterm]);
}
}
public static function save_invindex($filename, &$invindex)
{
file_put_contents($filename, json_encode($invindex));
}
public static function query_invindex($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];
// 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, $qterm));
}
// Consider matches in the page's tags
if(isset($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), $qterm));
}
}
}
foreach($matching_pages as $pageid => &$pagedata)
{
$pagedata["pagename"] = ids::getpagename($pageid);
$pagedata["rank"] = 0;
foreach($pagedata["nterms"] as $pterm => $entry)
{
$pagedata["rank"] += $entry["freq"];
// todo rank by context here
}
// Consider matches in the title / tags
if(isset($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 $matching_pages;
}
public static function extract_context($query, $source)
{
global $settings;
$nterms = self::tokenize($query);
$matches = [];
// Loop over each nterm and find it in the source
foreach($nterms as $nterm)
{
$all_offsets = mb_stripos_all($source, $nterm);
// Skip over adding matches if there aren't any
if($all_offsets === false)
continue;
foreach($all_offsets as $offset)
{
$matches[] = [ $nterm, $offset ];
}
}
usort($matches, function($a, $b) {
if($a[1] == $b[1]) return 0;
return ($a[1] < $b[1]) ? +1 : -1;
});
$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;
$context = substr($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);
$contexts[] = $context;
$basepos = $scanpos + 1;
}
return implode(" ... ", $contexts);
}
public static function highlight_context($query, $context)
{
$qterms = self::tokenize($query);
foreach($qterms as $qterm)
{
// From http://stackoverflow.com/a/2483859/1460422
$context = preg_replace("/" . str_replace("/", "\/", preg_quote($qterm)) . "/i", "<strong>$0</strong>", $context);
}
return $context;
}
}
?>