search/querylib.php

   1 <?php
   2   require_once("$CFG->dirroot/search/Zend/Search/Lucene.php");
   3
   4   class SearchResult {
   5     public  $url,
   6             $title,
   7             $doctype,
   8             $author,
   9             $score,
  10             $number;
  11   } //SearchResult
  12
  13
  14   //split this into Cache class and extend to SearchCache?
  15   class SearchCache {
  16     private $mode,
  17             $valid;
  18
  19     public function __construct($mode='session') {
  20       $accepted_modes = array('session');
  21
  22       if (in_array($mode, $accepted_modes)) {
  23         $this->mode = $mode;
  24       } else {
  25         $this->mode = 'session';
  26       } //else
  27
  28       $this->valid = true;
  29     } //constructor
  30
  31     public function can_cache() {
  32       return $this->valid;
  33     } //can_cache
  34
  35     public function cache($id=false, $object=false) {
  36       //see if there was a previous query
  37       $last_term = $this->fetch('search_last_term');
  38
  39       //if this query is different from the last, clear out the last one
  40       if ($id != false and $last_term != $id) {
  41         $this->clear($last_term);
  42       } //if
  43
  44       //store the new query if id and object are passed in
  45       if ($object and $id) {
  46         $this->store('search_last_term', $id);
  47         $this->store($id, $object);
  48         return true;
  49       //otherwise return the stored results
  50       } else if ($id and $this->exists($id)) {
  51         return $this->fetch($id);
  52       } //else
  53     } //cache
  54
  55     private function exists($id) {
  56       switch ($this->mode) {
  57         case 'session' :
  58           return isset($_SESSION[$id]);
  59       } //switch
  60     } //exists
  61
  62     private function clear($id) {
  63       switch ($this->mode) {
  64         case 'session' :
  65           unset($_SESSION[$id]);
  66           session_unregister($id);
  67           return;
  68       } //switch
  69     } //clear
  70
  71     private function fetch($id) {
  72       switch ($this->mode) {
  73         case 'session' :
  74           return ($this->exists($id)) ? unserialize($_SESSION[$id]) : false;
  75       } //switch
  76     } //fetch
  77
  78     private function store($id, $object) {
  79       switch ($this->mode) {
  80         case 'session' :
  81           $_SESSION[$id] = serialize($object);
  82           return;
  83       } //switch
  84     } //store
  85   } //SearchCache
  86
  87
  88   class SearchQuery {
  89     private $index,
  90             $term,
  91             $pagenumber,
  92             $cache,
  93             $validquery,
  94             $validindex,
  95             $results,
  96             $results_per_page,
  97             $total_results;
  98
  99     public function __construct($term='', $page=1, $results_per_page=10, $cache=false) {
 100       global $CFG;
 101
 102       $this->term       = $term;
 103       $this->pagenumber = $page;
 104       $this->cache      = $cache;
 105       $this->validquery = true;
 106       $this->validindex = true;
 107       $this->results_per_page = $results_per_page;
 108
 109       $index_path = SEARCH_INDEX_PATH;
 110
 111       try {
 112         $this->index = new Zend_Search_Lucene($index_path, false);
 113       } catch(Exception $e) {
 114         $this->validindex = false;
 115         return;
 116       } //catch
 117
 118       if (empty($this->term)) {
 119         $this->validquery = false;
 120       } else {
 121         $this->set_query($this->term);
 122       } //else
 123     } //constructor
 124
 125     public function set_query($term='') {
 126       if (!empty($term)) {
 127         $this->term = $term;
 128       } //if
 129
 130       if (empty($this->term)) {
 131         $this->validquery = false;
 132       } else {
 133         $this->validquery = true;
 134       } //else
 135
 136       if ($this->validquery and $this->validindex) {
 137         $this->results = $this->get_results();
 138       } else {
 139         $this->results = array();
 140       } //else
 141     } //set_query
 142
 143     public function results() {
 144       return $this->results;
 145     } //results
 146
 147     private function process_results($all=false) {
 148       global $USER;
 149
 150       $term = strtolower($this->term);
 151
 152       //experimental - return more results
 153       $strip_arr = array('author:', 'title:', '+', '-', 'doctype:');
 154       $stripped_term = str_replace($strip_arr, '', $term);
 155
 156       $hits = $this->index->find($term." title:".$stripped_term." author:".$stripped_term);
 157       //--
 158
 159       $hitcount = count($hits);
 160       $this->total_results = $hitcount;
 161
 162       if ($hitcount == 0) return array();
 163
 164       $totalpages = ceil($hitcount/$this->results_per_page);
 165
 166       if (!$all) {
 167         if ($hitcount < $this->results_per_page) {
 168           $this->pagenumber = 1;
 169         } else if ($this->pagenumber > $totalpages) {
 170           $this->pagenumber  =$totalpages;
 171         } //if
 172
 173         $start = ($this->pagenumber - 1) * $this->results_per_page;
 174         $end = $start + $this->results_per_page;
 175
 176         if ($end > $hitcount) {
 177           $end = $hitcount;
 178         } //if
 179       } else {
 180         $start = 0;
 181         $end = $hitcount;
 182       } //else
 183
 184       $resultdoc  = new SearchResult();
 185       $resultdocs = array();
 186
 187       for ($i = $start; $i < $end; $i++) {
 188         $hit = $hits[$i];
 189
 190         //check permissions on each result
 191         if ($this->can_display($USER, $hit->id, $hit->doctype, $hit->course_id, $hit->group_id)) {
 192           $resultdoc->number  = $i;
 193           $resultdoc->url     = $hit->url;
 194           $resultdoc->title   = $hit->title;
 195           $resultdoc->score   = $hit->score;
 196           $resultdoc->doctype = $hit->doctype;
 197           $resultdoc->author  = $hit->author;
 198
 199           //and store it
 200           $resultdocs[] = clone($resultdoc);
 201         } //if
 202       } //foreach
 203
 204       return $resultdocs;
 205     } //process_results
 206
 207     private function get_results() {
 208       $cache = new SearchCache();
 209
 210       if ($this->cache and $cache->can_cache()) {
 211         if (!($resultdocs = $cache->cache($this->term))) {
 212           $resultdocs = $this->process_results();
 213           //cache the results so we don't have to compute this on every page-load
 214           $cache->cache($this->term, $resultdocs);
 215           //print "Using new results.";
 216         } else {
 217           //There was something in the cache, so we're using that to save time
 218           //print "Using cached results.";
 219         } //else
 220       } else {
 221         //no caching :(
 222         //print "Caching disabled!";
 223         $resultdocs = $this->process_results();
 224       } //else
 225
 226       return $resultdocs;
 227     } //get_results
 228
 229     public function page_numbers() {
 230       $pages  = $this->total_pages();
 231       $query  = htmlentities($this->term);
 232       $page   = $this->pagenumber;
 233       $next   = "Next";
 234       $back   = "Back";
 235
 236       $ret = "<div align='center' id='search_page_links'>";
 237
 238       //Back is disabled if we're on page 1
 239       if ($page > 1) {
 240         $ret .= "<a href='query.php?query_string=$query&page=".($page-1)."'>< $back</a>&nbsp;";
 241       } else {
 242         $ret .= "< $back&nbsp;";
 243       } //else
 244
 245       //don't <a href> the current page
 246       for ($i = 1; $i <= $pages; $i++) {
 247         if ($page == $i) {
 248           $ret .= "[$i]&nbsp;";
 249         } else {
 250           $ret .= "<a href='query.php?query_string=$query&page=$i'>$i</a>&nbsp;";
 251         } //else
 252       } //for
 253
 254       //Next disabled if we're on the last page
 255       if ($page < $pages) {
 256         $ret .= "<a href='query.php?query_string=$query&page=".($page+1)."'>$next ></a>&nbsp;";
 257       } else {
 258         $ret .= "$next >&nbsp;";
 259       } //else
 260
 261       $ret .= "</div>";
 262
 263       //shorten really long page lists, to stop table distorting width-ways
 264       if (strlen($ret) > 70) {
 265         $start = 4;
 266         $end = $page - 5;
 267         $ret = preg_replace("/<a\D+\d+\D+>$start<\/a>.*?<a\D+\d+\D+>$end<\/a>/", '...', $ret);
 268
 269         $start = $page + 5;
 270         $end = $pages - 3;
 271         $ret = preg_replace("/<a\D+\d+\D+>$start<\/a>.*?<a\D+\d+\D+>$end<\/a>/", '...', $ret);
 272       } //if
 273
 274       return $ret;
 275     } //page_numbers
 276
 277     //can the user see this result?
 278     private function can_display(&$user, $this_id, $doctype, $course_id, $group_id) {
 279       //this function should return true/false depending on
 280       //whether or not a user can see this resource
 281       //..
 282       //if one of you nice moodlers see this, feel free to
 283       //implement it for me .. :-P
 284       return true;
 285     } //can_display
 286
 287     public function count() {
 288       return $this->total_results;
 289     } //count
 290
 291     public function is_valid() {
 292       return ($this->validquery and $this->validindex);
 293     } //is_valid
 294
 295     public function is_valid_query() {
 296       return $this->validquery;
 297     } //is_valid_query
 298
 299     public function is_valid_index() {
 300       return $this->validindex;
 301     } //is_valid_index
 302
 303     public function total_pages() {
 304       return ceil($this->count()/$this->results_per_page);
 305     } //pages
 306
 307     public function get_pagenumber() {
 308       return $this->pagenumber;
 309     } //get_pagenumber
 310
 311     public function get_results_per_page() {
 312       return $this->results_per_page;
 313     } //get_results_per_page
 314   } //SearchQuery
 315
 316 ?>