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 $myLinks[350]['title'];
  10  *    foreach ($myLinks as $link)
  11  *       echo $link['title'].' at url '.$link['url'].'; description:'.$link['description'];
  12  *
  13  * Available keys:
  14  *  - id:       primary key, incremental integer identifier (persistent)
  15  *  - description: description of the entry
  16  *  - created:  creation date of this entry, DateTime object.
  17  *  - updated:  last modification date of this entry, DateTime object.
  18  *  - private:  Is this link private? 0=no, other value=yes
  19  *  - tags:     tags attached to this entry (separated by spaces)
  20  *  - title     Title of the link
  21  *  - url       URL of the link. Used for displayable links (no redirector, relative, etc.).
  22  *              Can be absolute or relative.
  23  *              Relative URLs are permalinks (e.g.'?m-ukcw')
  24  *  - real_url  Absolute processed URL.
  25  *  - shorturl  Permalink smallhash
  26  *
  27  * Implements 3 interfaces:
  28  *  - ArrayAccess: behaves like an associative array;
  29  *  - Countable:   there is a count() method;
  30  *  - Iterator:    usable in foreach () loops.
  31  *
  32  * ID mechanism:
  33  *   ArrayAccess is implemented in a way that will allow to access a link
  34  *   with the unique identifier ID directly with $link[ID].
  35  *   Note that it's not the real key of the link array attribute.
  36  *   This mechanism is in place to have persistent link IDs,
  37  *   even though the internal array is reordered by date.
  38  *   Example:
  39  *     - DB: link #1 (2010-01-01) link #2 (2016-01-01)
  40  *     - Order: #2 #1
  41  *     - Import links containing: link #3 (2013-01-01)
  42  *     - New DB: link #1 (2010-01-01) link #2 (2016-01-01) link #3 (2013-01-01)
  43  *     - Real order: #2 #3 #1
  44  */
  45 class LinkDB implements Iterator, Countable, ArrayAccess
  46 {
  47     // Links are stored as a PHP serialized string
  48     private $datastore;
  49
  50     // Link date storage format
  51     const LINK_DATE_FORMAT = 'Ymd_His';
  52
  53     // List of links (associative array)
  54     //  - key:   link date (e.g. "20110823_124546"),
  55     //  - value: associative array (keys: title, description...)
  56     private $links;
  57
  58     // List of all recorded URLs (key=url, value=link offset)
  59     // for fast reserve search (url-->link offset)
  60     private $urls;
  61
  62     /**
  63      * @var array List of all links IDS mapped with their array offset.
  64      *            Map: id->offset.
  65      */
  66     protected $ids;
  67
  68     // List of offset keys (for the Iterator interface implementation)
  69     private $keys;
  70
  71     // Position in the $this->keys array (for the Iterator interface)
  72     private $position;
  73
  74     // Is the user logged in? (used to filter private links)
  75     private $loggedIn;
  76
  77     // Hide public links
  78     private $hidePublicLinks;
  79
  80     // link redirector set in user settings.
  81     private $redirector;
  82
  83     /**
  84      * Set this to `true` to urlencode link behind redirector link, `false` to leave it untouched.
  85      *
  86      * Example:
  87      *   anonym.to needs clean URL while dereferer.org needs urlencoded URL.
  88      *
  89      * @var boolean $redirectorEncode parameter: true or false
  90      */
  91     private $redirectorEncode;
  92
  93     /**
  94      * Creates a new LinkDB
  95      *
  96      * Checks if the datastore exists; else, attempts to create a dummy one.
  97      *
  98      * @param string  $datastore        datastore file path.
  99      * @param boolean $isLoggedIn       is the user logged in?
 100      * @param boolean $hidePublicLinks  if true all links are private.
 101      * @param string  $redirector       link redirector set in user settings.
 102      * @param boolean $redirectorEncode Enable urlencode on redirected urls (default: true).
 103      */
 104     public function __construct(
 105         $datastore,
 106         $isLoggedIn,
 107         $hidePublicLinks,
 108         $redirector = '',
 109         $redirectorEncode = true
 110     )
 111     {
 112         $this->datastore = $datastore;
 113         $this->loggedIn = $isLoggedIn;
 114         $this->hidePublicLinks = $hidePublicLinks;
 115         $this->redirector = $redirector;
 116         $this->redirectorEncode = $redirectorEncode === true;
 117         $this->check();
 118         $this->read();
 119     }
 120
 121     /**
 122      * Countable - Counts elements of an object
 123      */
 124     public function count()
 125     {
 126         return count($this->links);
 127     }
 128
 129     /**
 130      * ArrayAccess - Assigns a value to the specified offset
 131      */
 132     public function offsetSet($offset, $value)
 133     {
 134         // TODO: use exceptions instead of "die"
 135         if (!$this->loggedIn) {
 136             die(t('You are not authorized to add a link.'));
 137         }
 138         if (!isset($value['id']) || empty($value['url'])) {
 139             die(t('Internal Error: A link should always have an id and URL.'));
 140         }
 141         if (($offset !== null && ! is_int($offset)) || ! is_int($value['id'])) {
 142             die(t('You must specify an integer as a key.'));
 143         }
 144         if ($offset !== null && $offset !== $value['id']) {
 145             die(t('Array offset and link ID must be equal.'));
 146         }
 147
 148         // If the link exists, we reuse the real offset, otherwise new entry
 149         $existing = $this->getLinkOffset($offset);
 150         if ($existing !== null) {
 151             $offset = $existing;
 152         } else {
 153             $offset = count($this->links);
 154         }
 155         $this->links[$offset] = $value;
 156         $this->urls[$value['url']] = $offset;
 157         $this->ids[$value['id']] = $offset;
 158     }
 159
 160     /**
 161      * ArrayAccess - Whether or not an offset exists
 162      */
 163     public function offsetExists($offset)
 164     {
 165         return array_key_exists($this->getLinkOffset($offset), $this->links);
 166     }
 167
 168     /**
 169      * ArrayAccess - Unsets an offset
 170      */
 171     public function offsetUnset($offset)
 172     {
 173         if (!$this->loggedIn) {
 174             // TODO: raise an exception
 175             die('You are not authorized to delete a link.');
 176         }
 177         $realOffset = $this->getLinkOffset($offset);
 178         $url = $this->links[$realOffset]['url'];
 179         unset($this->urls[$url]);
 180         unset($this->ids[$realOffset]);
 181         unset($this->links[$realOffset]);
 182     }
 183
 184     /**
 185      * ArrayAccess - Returns the value at specified offset
 186      */
 187     public function offsetGet($offset)
 188     {
 189         $realOffset = $this->getLinkOffset($offset);
 190         return isset($this->links[$realOffset]) ? $this->links[$realOffset] : null;
 191     }
 192
 193     /**
 194      * Iterator - Returns the current element
 195      */
 196     public function current()
 197     {
 198         return $this[$this->keys[$this->position]];
 199     }
 200
 201     /**
 202      * Iterator - Returns the key of the current element
 203      */
 204     public function key()
 205     {
 206         return $this->keys[$this->position];
 207     }
 208
 209     /**
 210      * Iterator - Moves forward to next element
 211      */
 212     public function next()
 213     {
 214         ++$this->position;
 215     }
 216
 217     /**
 218      * Iterator - Rewinds the Iterator to the first element
 219      *
 220      * Entries are sorted by date (latest first)
 221      */
 222     public function rewind()
 223     {
 224         $this->keys = array_keys($this->ids);
 225         $this->position = 0;
 226     }
 227
 228     /**
 229      * Iterator - Checks if current position is valid
 230      */
 231     public function valid()
 232     {
 233         return isset($this->keys[$this->position]);
 234     }
 235
 236     /**
 237      * Checks if the DB directory and file exist
 238      *
 239      * If no DB file is found, creates a dummy DB.
 240      */
 241     private function check()
 242     {
 243         if (file_exists($this->datastore)) {
 244             return;
 245         }
 246
 247         // Create a dummy database for example
 248         $this->links = array();
 249         $link = array(
 250             'id' => 1,
 251             'title'=> t('The personal, minimalist, super-fast, database free, bookmarking service'),
 252             'url'=>'https://shaarli.readthedocs.io',
 253             'description'=>t('Welcome to Shaarli! This is your first public bookmark. To edit or delete me, you must first login.
 254
 255 To learn how to use Shaarli, consult the link "Documentation" at the bottom of this page.
 256
 257 You use the community supported version of the original Shaarli project, by Sebastien Sauvage.'),
 258             'private'=>0,
 259             'created'=> new DateTime(),
 260             'tags'=>'opensource software'
 261         );
 262         $link['shorturl'] = link_small_hash($link['created'], $link['id']);
 263         $this->links[1] = $link;
 264
 265         $link = array(
 266             'id' => 0,
 267             'title'=> t('My secret stuff... - Pastebin.com'),
 268             'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
 269             'description'=> t('Shhhh! I\'m a private link only YOU can see. You can delete me too.'),
 270             'private'=>1,
 271             'created'=> new DateTime('1 minute ago'),
 272             'tags'=>'secretstuff',
 273         );
 274         $link['shorturl'] = link_small_hash($link['created'], $link['id']);
 275         $this->links[0] = $link;
 276
 277         // Write database to disk
 278         $this->write();
 279     }
 280
 281     /**
 282      * Reads database from disk to memory
 283      */
 284     private function read()
 285     {
 286         // Public links are hidden and user not logged in => nothing to show
 287         if ($this->hidePublicLinks && !$this->loggedIn) {
 288             $this->links = array();
 289             return;
 290         }
 291
 292         $this->links = FileUtils::readFlatDB($this->datastore, []);
 293
 294         $toremove = array();
 295         foreach ($this->links as $key => &$link) {
 296             if (! $this->loggedIn && $link['private'] != 0) {
 297                 // Transition for not upgraded databases.
 298                 $toremove[] = $key;
 299                 continue;
 300             }
 301
 302             // Sanitize data fields.
 303             sanitizeLink($link);
 304
 305             // Remove private tags if the user is not logged in.
 306             if (! $this->loggedIn) {
 307                 $link['tags'] = preg_replace('/(^|\s+)\.[^($|\s)]+\s*/', ' ', $link['tags']);
 308             }
 309
 310             // Do not use the redirector for internal links (Shaarli note URL starting with a '?').
 311             if (!empty($this->redirector) && !startsWith($link['url'], '?')) {
 312                 $link['real_url'] = $this->redirector;
 313                 if ($this->redirectorEncode) {
 314                     $link['real_url'] .= urlencode(unescape($link['url']));
 315                 } else {
 316                     $link['real_url'] .= $link['url'];
 317                 }
 318             }
 319             else {
 320                 $link['real_url'] = $link['url'];
 321             }
 322
 323             // To be able to load links before running the update, and prepare the update
 324             if (! isset($link['created'])) {
 325                 $link['id'] = $link['linkdate'];
 326                 $link['created'] = DateTime::createFromFormat(self::LINK_DATE_FORMAT, $link['linkdate']);
 327                 if (! empty($link['updated'])) {
 328                     $link['updated'] = DateTime::createFromFormat(self::LINK_DATE_FORMAT, $link['updated']);
 329                 }
 330                 $link['shorturl'] = smallHash($link['linkdate']);
 331             }
 332         }
 333
 334         // If user is not logged in, filter private links.
 335         foreach ($toremove as $offset) {
 336             unset($this->links[$offset]);
 337         }
 338
 339         $this->reorder();
 340     }
 341
 342     /**
 343      * Saves the database from memory to disk
 344      *
 345      * @throws IOException the datastore is not writable
 346      */
 347     private function write()
 348     {
 349         FileUtils::writeFlatDB($this->datastore, $this->links);
 350     }
 351
 352     /**
 353      * Saves the database from memory to disk
 354      *
 355      * @param string $pageCacheDir page cache directory
 356      */
 357     public function save($pageCacheDir)
 358     {
 359         if (!$this->loggedIn) {
 360             // TODO: raise an Exception instead
 361             die('You are not authorized to change the database.');
 362         }
 363
 364         $this->write();
 365
 366         invalidateCaches($pageCacheDir);
 367     }
 368
 369     /**
 370      * Returns the link for a given URL, or False if it does not exist.
 371      *
 372      * @param string $url URL to search for
 373      *
 374      * @return mixed the existing link if it exists, else 'false'
 375      */
 376     public function getLinkFromUrl($url)
 377     {
 378         if (isset($this->urls[$url])) {
 379             return $this->links[$this->urls[$url]];
 380         }
 381         return false;
 382     }
 383
 384     /**
 385      * Returns the shaare corresponding to a smallHash.
 386      *
 387      * @param string $request QUERY_STRING server parameter.
 388      *
 389      * @return array $filtered array containing permalink data.
 390      *
 391      * @throws LinkNotFoundException if the smallhash is malformed or doesn't match any link.
 392      */
 393     public function filterHash($request)
 394     {
 395         $request = substr($request, 0, 6);
 396         $linkFilter = new LinkFilter($this->links);
 397         return $linkFilter->filter(LinkFilter::$FILTER_HASH, $request);
 398     }
 399
 400     /**
 401      * Returns the list of articles for a given day.
 402      *
 403      * @param string $request day to filter. Format: YYYYMMDD.
 404      *
 405      * @return array list of shaare found.
 406      */
 407     public function filterDay($request) {
 408         $linkFilter = new LinkFilter($this->links);
 409         return $linkFilter->filter(LinkFilter::$FILTER_DAY, $request);
 410     }
 411
 412     /**
 413      * Filter links according to search parameters.
 414      *
 415      * @param array  $filterRequest Search request content. Supported keys:
 416      *                                - searchtags: list of tags
 417      *                                - searchterm: term search
 418      * @param bool   $casesensitive Optional: Perform case sensitive filter
 419      * @param string $visibility    return only all/private/public links
 420      * @param string $untaggedonly  return only untagged links
 421      *
 422      * @return array filtered links, all links if no suitable filter was provided.
 423      */
 424     public function filterSearch($filterRequest = array(), $casesensitive = false, $visibility = 'all', $untaggedonly = false)
 425     {
 426         // Filter link database according to parameters.
 427         $searchtags = isset($filterRequest['searchtags']) ? escape($filterRequest['searchtags']) : '';
 428         $searchterm = isset($filterRequest['searchterm']) ? escape($filterRequest['searchterm']) : '';
 429
 430         // Search tags + fullsearch - blank string parameter will return all links.
 431         $type = LinkFilter::$FILTER_TAG | LinkFilter::$FILTER_TEXT; // == "vuotext"
 432         $request = [$searchtags, $searchterm];
 433
 434         $linkFilter = new LinkFilter($this);
 435         return $linkFilter->filter($type, $request, $casesensitive, $visibility, $untaggedonly);
 436     }
 437
 438     /**
 439      * Returns the list tags appearing in the links with the given tags
 440      * @param $filteringTags: tags selecting the links to consider
 441      * @param $visibility: process only all/private/public links
 442      * @return: a tag=>linksCount array
 443      */
 444     public function linksCountPerTag($filteringTags = [], $visibility = 'all')
 445     {
 446         $links = empty($filteringTags) ? $this->links : $this->filterSearch(['searchtags' => $filteringTags], false, $visibility);
 447         $tags = array();
 448         $caseMapping = array();
 449         foreach ($links as $link) {
 450             foreach (preg_split('/\s+/', $link['tags'], 0, PREG_SPLIT_NO_EMPTY) as $tag) {
 451                 if (empty($tag)) {
 452                     continue;
 453                 }
 454                 // The first case found will be displayed.
 455                 if (!isset($caseMapping[strtolower($tag)])) {
 456                     $caseMapping[strtolower($tag)] = $tag;
 457                     $tags[$caseMapping[strtolower($tag)]] = 0;
 458                 }
 459                 $tags[$caseMapping[strtolower($tag)]]++;
 460             }
 461         }
 462         // Sort tags by usage (most used tag first)
 463         arsort($tags);
 464         return $tags;
 465     }
 466
 467     /**
 468      * Rename or delete a tag across all links.
 469      *
 470      * @param string $from Tag to rename
 471      * @param string $to   New tag. If none is provided, the from tag will be deleted
 472      *
 473      * @return array|bool List of altered links or false on error
 474      */
 475     public function renameTag($from, $to)
 476     {
 477         if (empty($from)) {
 478             return false;
 479         }
 480         $delete = empty($to);
 481         // True for case-sensitive tag search.
 482         $linksToAlter = $this->filterSearch(['searchtags' => $from], true);
 483         foreach($linksToAlter as $key => &$value)
 484         {
 485             $tags = preg_split('/\s+/', trim($value['tags']));
 486             if (($pos = array_search($from, $tags)) !== false) {
 487                 if ($delete) {
 488                     unset($tags[$pos]); // Remove tag.
 489                 } else {
 490                     $tags[$pos] = trim($to);
 491                 }
 492                 $value['tags'] = trim(implode(' ', array_unique($tags)));
 493                 $this[$value['id']] = $value;
 494             }
 495         }
 496
 497         return $linksToAlter;
 498     }
 499
 500     /**
 501      * Returns the list of days containing articles (oldest first)
 502      * Output: An array containing days (in format YYYYMMDD).
 503      */
 504     public function days()
 505     {
 506         $linkDays = array();
 507         foreach ($this->links as $link) {
 508             $linkDays[$link['created']->format('Ymd')] = 0;
 509         }
 510         $linkDays = array_keys($linkDays);
 511         sort($linkDays);
 512
 513         return $linkDays;
 514     }
 515
 516     /**
 517      * Reorder links by creation date (newest first).
 518      *
 519      * Also update the urls and ids mapping arrays.
 520      *
 521      * @param string $order ASC|DESC
 522      */
 523     public function reorder($order = 'DESC')
 524     {
 525         $order = $order === 'ASC' ? -1 : 1;
 526         // Reorder array by dates.
 527         usort($this->links, function($a, $b) use ($order) {
 528             return $a['created'] < $b['created'] ? 1 * $order : -1 * $order;
 529         });
 530
 531         $this->urls = array();
 532         $this->ids = array();
 533         foreach ($this->links as $key => $link) {
 534             $this->urls[$link['url']] = $key;
 535             $this->ids[$link['id']] = $key;
 536         }
 537     }
 538
 539     /**
 540      * Return the next key for link creation.
 541      * E.g. If the last ID is 597, the next will be 598.
 542      *
 543      * @return int next ID.
 544      */
 545     public function getNextId()
 546     {
 547         if (!empty($this->ids)) {
 548             return max(array_keys($this->ids)) + 1;
 549         }
 550         return 0;
 551     }
 552
 553     /**
 554      * Returns a link offset in links array from its unique ID.
 555      *
 556      * @param int $id Persistent ID of a link.
 557      *
 558      * @return int Real offset in local array, or null if doesn't exist.
 559      */
 560     protected function getLinkOffset($id)
 561     {
 562         if (isset($this->ids[$id])) {
 563             return $this->ids[$id];
 564         }
 565         return null;
 566     }
 567 }