application/LinkDB.php

   1 <?php
   2 /**
   3  * Data storage for links.
   4  *
   5  * This object behaves like an associative array.
   6  *
   7  * Example:
   8  *    $myLinks = new LinkDB();
   9  *    echo $myLinks['20110826_161819']['title'];
  10  *    foreach ($myLinks as $link)
  11  *       echo $link['title'].' at url '.$link['url'].'; description:'.$link['description'];
  12  *
  13  * Available keys:
  14  *  - description: description of the entry
  15  *  - linkdate: date of the creation of this entry, in the form YYYYMMDD_HHMMSS
  16  *              (e.g.'20110914_192317')
  17  *  - private:  Is this link private? 0=no, other value=yes
  18  *  - tags:     tags attached to this entry (separated by spaces)
  19  *  - title     Title of the link
  20  *  - url       URL of the link. Can be absolute or relative.
  21  *              Relative URLs are permalinks (e.g.'?m-ukcw')
  22  *
  23  * Implements 3 interfaces:
  24  *  - ArrayAccess: behaves like an associative array;
  25  *  - Countable:   there is a count() method;
  26  *  - Iterator:    usable in foreach () loops.
  27  */
  28 class LinkDB implements Iterator, Countable, ArrayAccess
  29 {
  30     // List of links (associative array)
  31     //  - key:   link date (e.g. "20110823_124546"),
  32     //  - value: associative array (keys: title, description...)
  33     private $links;
  34
  35     // List of all recorded URLs (key=url, value=linkdate)
  36     // for fast reserve search (url-->linkdate)
  37     private $urls;
  38
  39     // List of linkdate keys (for the Iterator interface implementation)
  40     private $keys;
  41
  42     // Position in the $this->keys array (for the Iterator interface)
  43     private $position;
  44
  45     // Is the user logged in? (used to filter private links)
  46     private $loggedIn;
  47
  48     // Hide public links
  49     private $hidePublicLinks;
  50
  51     /**
  52      * Creates a new LinkDB
  53      *
  54      * Checks if the datastore exists; else, attempts to create a dummy one.
  55      *
  56      * @param $isLoggedIn is the user logged in?
  57      */
  58     function __construct($isLoggedIn, $hidePublicLinks)
  59     {
  60         // FIXME: do not access $GLOBALS, pass the datastore instead
  61         $this->loggedIn = $isLoggedIn;
  62         $this->hidePublicLinks = $hidePublicLinks;
  63         $this->checkDB();
  64         $this->readdb();
  65     }
  66
  67     /**
  68      * Countable - Counts elements of an object
  69      */
  70     public function count()
  71     {
  72         return count($this->links);
  73     }
  74
  75     /**
  76      * ArrayAccess - Assigns a value to the specified offset
  77      */
  78     public function offsetSet($offset, $value)
  79     {
  80         // TODO: use exceptions instead of "die"
  81         if (!$this->loggedIn) {
  82             die('You are not authorized to add a link.');
  83         }
  84         if (empty($value['linkdate']) || empty($value['url'])) {
  85             die('Internal Error: A link should always have a linkdate and URL.');
  86         }
  87         if (empty($offset)) {
  88             die('You must specify a key.');
  89         }
  90         $this->links[$offset] = $value;
  91         $this->urls[$value['url']]=$offset;
  92     }
  93
  94     /**
  95      * ArrayAccess - Whether or not an offset exists
  96      */
  97     public function offsetExists($offset)
  98     {
  99         return array_key_exists($offset, $this->links);
 100     }
 101
 102     /**
 103      * ArrayAccess - Unsets an offset
 104      */
 105     public function offsetUnset($offset)
 106     {
 107         if (!$this->loggedIn) {
 108             // TODO: raise an exception
 109             die('You are not authorized to delete a link.');
 110         }
 111         $url = $this->links[$offset]['url'];
 112         unset($this->urls[$url]);
 113         unset($this->links[$offset]);
 114     }
 115
 116     /**
 117      * ArrayAccess - Returns the value at specified offset
 118      */
 119     public function offsetGet($offset)
 120     {
 121         return isset($this->links[$offset]) ? $this->links[$offset] : null;
 122     }
 123
 124     /**
 125      * Iterator - Returns the current element
 126      */
 127     function current()
 128     {
 129         return $this->links[$this->keys[$this->position]];
 130     }
 131
 132     /**
 133      * Iterator - Returns the key of the current element
 134      */
 135     function key()
 136     {
 137         return $this->keys[$this->position];
 138     }
 139
 140     /**
 141      * Iterator - Moves forward to next element
 142      */
 143     function next()
 144     {
 145         ++$this->position;
 146     }
 147
 148     /**
 149      * Iterator - Rewinds the Iterator to the first element
 150      *
 151      * Entries are sorted by date (latest first)
 152      */
 153     function rewind()
 154     {
 155         $this->keys = array_keys($this->links);
 156         rsort($this->keys);
 157         $this->position = 0;
 158     }
 159
 160     /**
 161      * Iterator - Checks if current position is valid
 162      */
 163     function valid()
 164     {
 165         return isset($this->keys[$this->position]);
 166     }
 167
 168     /**
 169      * Checks if the DB directory and file exist
 170      *
 171      * If no DB file is found, creates a dummy DB.
 172      */
 173     private function checkDB()
 174     {
 175         if (file_exists($GLOBALS['config']['DATASTORE'])) {
 176             return;
 177         }
 178
 179         // Create a dummy database for example
 180         $this->links = array();
 181         $link = array(
 182             'title'=>'Shaarli - sebsauvage.net',
 183             'url'=>'http://sebsauvage.net/wiki/doku.php?id=php:shaarli',
 184             'description'=>'Welcome to Shaarli! This is a bookmark. To edit or delete me, you must first login.',
 185             'private'=>0,
 186             'linkdate'=>'20110914_190000',
 187             'tags'=>'opensource software'
 188         );
 189         $this->links[$link['linkdate']] = $link;
 190
 191         $link = array(
 192             'title'=>'My secret stuff... - Pastebin.com',
 193             'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
 194             'description'=>'SShhhh!!  I\'m a private link only YOU can see. You can delete me too.',
 195             'private'=>1,
 196             'linkdate'=>'20110914_074522',
 197             'tags'=>'secretstuff'
 198         );
 199         $this->links[$link['linkdate']] = $link;
 200
 201         // Write database to disk
 202         // TODO: raise an exception if the file is not write-able
 203         file_put_contents(
 204             // FIXME: do not use $GLOBALS
 205             $GLOBALS['config']['DATASTORE'],
 206             PHPPREFIX.base64_encode(gzdeflate(serialize($this->links))).PHPSUFFIX
 207         );
 208     }
 209
 210     /**
 211      * Reads database from disk to memory
 212      */
 213     private function readdb()
 214     {
 215
 216         // Public links are hidden and user not logged in => nothing to show
 217         if ($this->hidePublicLinks && !$this->loggedIn) {
 218             $this->links = array();
 219             return;
 220         }
 221
 222         // Read data
 223         // Note that gzinflate is faster than gzuncompress.
 224         // See: http://www.php.net/manual/en/function.gzdeflate.php#96439
 225         // FIXME: do not use $GLOBALS
 226         $this->links = array();
 227
 228         if (file_exists($GLOBALS['config']['DATASTORE'])) {
 229             $this->links = unserialize(gzinflate(base64_decode(
 230                 substr(file_get_contents($GLOBALS['config']['DATASTORE']),
 231                        strlen(PHPPREFIX), -strlen(PHPSUFFIX)))));
 232         }
 233
 234         // If user is not logged in, filter private links.
 235         if (!$this->loggedIn) {
 236             $toremove = array();
 237             foreach ($this->links as $link) {
 238                 if ($link['private'] != 0) {
 239                     $toremove[] = $link['linkdate'];
 240                 }
 241             }
 242             foreach ($toremove as $linkdate) {
 243                 unset($this->links[$linkdate]);
 244             }
 245         }
 246
 247         // Keep the list of the mapping URLs-->linkdate up-to-date.
 248         $this->urls = array();
 249         foreach ($this->links as $link) {
 250             $this->urls[$link['url']] = $link['linkdate'];
 251         }
 252
 253         // Escape links data
 254         foreach($this->links as &$link) {
 255             sanitizeLink($link);
 256         }
 257     }
 258
 259     /**
 260      * Saves the database from memory to disk
 261      */
 262     public function savedb()
 263     {
 264         if (!$this->loggedIn) {
 265             // TODO: raise an Exception instead
 266             die('You are not authorized to change the database.');
 267         }
 268         file_put_contents(
 269             $GLOBALS['config']['DATASTORE'],
 270             PHPPREFIX.base64_encode(gzdeflate(serialize($this->links))).PHPSUFFIX
 271         );
 272         invalidateCaches();
 273     }
 274
 275     /**
 276      * Returns the link for a given URL, or False if it does not exist.
 277      */
 278     public function getLinkFromUrl($url)
 279     {
 280         if (isset($this->urls[$url])) {
 281             return $this->links[$this->urls[$url]];
 282         }
 283         return false;
 284     }
 285
 286     /**
 287      * Returns the list of links corresponding to a full-text search
 288      *
 289      * Searches:
 290      *  - in the URLs, title and description;
 291      *  - are case-insensitive.
 292      *
 293      * Example:
 294      *    print_r($mydb->filterFulltext('hollandais'));
 295      *
 296      * mb_convert_case($val, MB_CASE_LOWER, 'UTF-8')
 297      *  - allows to perform searches on Unicode text
 298      *  - see https://github.com/shaarli/Shaarli/issues/75 for examples
 299      */
 300     public function filterFulltext($searchterms)
 301     {
 302         // FIXME: explode(' ',$searchterms) and perform a AND search.
 303         // FIXME: accept double-quotes to search for a string "as is"?
 304         $filtered = array();
 305         $search = mb_convert_case($searchterms, MB_CASE_LOWER, 'UTF-8');
 306         $keys = ['title', 'description', 'url', 'tags'];
 307
 308         foreach ($this->links as $link) {
 309             $found = false;
 310
 311             foreach ($keys as $key) {
 312                 if (strpos(mb_convert_case($link[$key], MB_CASE_LOWER, 'UTF-8'),
 313                            $search) !== false) {
 314                     $found = true;
 315                 }
 316             }
 317
 318             if ($found) {
 319                 $filtered[$link['linkdate']] = $link;
 320             }
 321         }
 322         krsort($filtered);
 323         return $filtered;
 324     }
 325
 326     /**
 327      * Returns the list of links associated with a given list of tags
 328      *
 329      * You can specify one or more tags, separated by space or a comma, e.g.
 330      *  print_r($mydb->filterTags('linux programming'));
 331      */
 332     public function filterTags($tags, $casesensitive=false)
 333     {
 334         // Same as above, we use UTF-8 conversion to handle various graphemes (i.e. cyrillic, or greek)
 335         // FIXME: is $casesensitive ever true?
 336         $t = str_replace(
 337             ',', ' ',
 338             ($casesensitive ? $tags : mb_convert_case($tags, MB_CASE_LOWER, 'UTF-8'))
 339         );
 340
 341         $searchtags = explode(' ', $t);
 342         $filtered = array();
 343
 344         foreach ($this->links as $l) {
 345             $linktags = explode(
 346                 ' ',
 347                 ($casesensitive ? $l['tags']:mb_convert_case($l['tags'], MB_CASE_LOWER, 'UTF-8'))
 348             );
 349
 350             if (count(array_intersect($linktags, $searchtags)) == count($searchtags)) {
 351                 $filtered[$l['linkdate']] = $l;
 352             }
 353         }
 354         krsort($filtered);
 355         return $filtered;
 356     }
 357
 358
 359     /**
 360      * Returns the list of articles for a given day, chronologically sorted
 361      *
 362      * Day must be in the form 'YYYYMMDD' (e.g. '20120125'), e.g.
 363      *  print_r($mydb->filterDay('20120125'));
 364      */
 365     public function filterDay($day)
 366     {
 367         // TODO: check input format
 368         $filtered = array();
 369         foreach ($this->links as $l) {
 370             if (startsWith($l['linkdate'], $day)) {
 371                 $filtered[$l['linkdate']] = $l;
 372             }
 373         }
 374         ksort($filtered);
 375         return $filtered;
 376     }
 377
 378     /**
 379      * Returns the article corresponding to a smallHash
 380      */
 381     public function filterSmallHash($smallHash)
 382     {
 383         $filtered = array();
 384         foreach ($this->links as $l) {
 385             if ($smallHash == smallHash($l['linkdate'])) {
 386                 // Yes, this is ugly and slow
 387                 $filtered[$l['linkdate']] = $l;
 388                 return $filtered;
 389             }
 390         }
 391         return $filtered;
 392     }
 393
 394     /**
 395      * Returns the list of all tags
 396      * Output: associative array key=tags, value=0
 397      */
 398     public function allTags()
 399     {
 400         $tags = array();
 401         foreach ($this->links as $link) {
 402             foreach (explode(' ', $link['tags']) as $tag) {
 403                 if (!empty($tag)) {
 404                     $tags[$tag] = (empty($tags[$tag]) ? 1 : $tags[$tag] + 1);
 405                 }
 406             }
 407         }
 408         // Sort tags by usage (most used tag first)
 409         arsort($tags);
 410         return $tags;
 411     }
 412
 413     /**
 414      * Returns the list of days containing articles (oldest first)
 415      * Output: An array containing days (in format YYYYMMDD).
 416      */
 417     public function days()
 418     {
 419         $linkDays = array();
 420         foreach (array_keys($this->links) as $day) {
 421             $linkDays[substr($day, 0, 8)] = 0;
 422         }
 423         $linkDays = array_keys($linkDays);
 424         sort($linkDays);
 425         return $linkDays;
 426     }
 427 }
 428 ?>