<?php
/**
* Data storage for links.
*
* This object behaves like an associative array.
*
* Example:
* $myLinks = new LinkDB();
* echo $myLinks['20110826_161819']['title'];
* foreach ($myLinks as $link)
* echo $link['title'].' at url '.$link['url'].'; description:'.$link['description'];
*
* Available keys:
* - description: description of the entry
* - linkdate: date of the creation of this entry, in the form YYYYMMDD_HHMMSS
* (e.g.'20110914_192317')
* - private: Is this link private? 0=no, other value=yes
* - tags: tags attached to this entry (separated by spaces)
* - title Title of the link
* - url URL of the link. Used for displayable links (no redirector, relative, etc.).
* Can be absolute or relative.
* Relative URLs are permalinks (e.g.'?m-ukcw')
* - real_url Absolute processed URL.
*
* Implements 3 interfaces:
* - ArrayAccess: behaves like an associative array;
* - Countable: there is a count() method;
* - Iterator: usable in foreach () loops.
*/
class LinkDB implements Iterator, Countable, ArrayAccess
{
// Links are stored as a PHP serialized string
private $_datastore;
// Link date storage format
const LINK_DATE_FORMAT = 'Ymd_His';
// Datastore PHP prefix
protected static $phpPrefix = '<?php /* ';
// Datastore PHP suffix
protected static $phpSuffix = ' */ ?>';
// List of links (associative array)
// - key: link date (e.g. "20110823_124546"),
// - value: associative array (keys: title, description...)
private $_links;
// List of all recorded URLs (key=url, value=linkdate)
// for fast reserve search (url-->linkdate)
private $_urls;
// List of linkdate keys (for the Iterator interface implementation)
private $_keys;
// Position in the $this->_keys array (for the Iterator interface)
private $_position;
// Is the user logged in? (used to filter private links)
private $_loggedIn;
// Hide public links
private $_hidePublicLinks;
// link redirector set in user settings.
private $_redirector;
/**
* Set this to `true` to urlencode link behind redirector link, `false` to leave it untouched.
*
* Example:
* anonym.to needs clean URL while dereferer.org needs urlencoded URL.
*
* @var boolean $redirectorEncode parameter: true or false
*/
private $redirectorEncode;
/**
* Creates a new LinkDB
*
* Checks if the datastore exists; else, attempts to create a dummy one.
*
* @param string $datastore datastore file path.
* @param boolean $isLoggedIn is the user logged in?
* @param boolean $hidePublicLinks if true all links are private.
* @param string $redirector link redirector set in user settings.
* @param boolean $redirectorEncode Enable urlencode on redirected urls (default: true).
*/
function __construct(
$datastore,
$isLoggedIn,
$hidePublicLinks,
$redirector = '',
$redirectorEncode = true
)
{
$this->_datastore = $datastore;
$this->_loggedIn = $isLoggedIn;
$this->_hidePublicLinks = $hidePublicLinks;
$this->_redirector = $redirector;
$this->redirectorEncode = $redirectorEncode === true;
$this->_checkDB();
$this->_readDB();
}
/**
* Countable - Counts elements of an object
*/
public function count()
{
return count($this->_links);
}
/**
* ArrayAccess - Assigns a value to the specified offset
*/
public function offsetSet($offset, $value)
{
// TODO: use exceptions instead of "die"
if (!$this->_loggedIn) {
die('You are not authorized to add a link.');
}
if (empty($value['linkdate']) || empty($value['url'])) {
die('Internal Error: A link should always have a linkdate and URL.');
}
if (empty($offset)) {
die('You must specify a key.');
}
$this->_links[$offset] = $value;
$this->_urls[$value['url']]=$offset;
}
/**
* ArrayAccess - Whether or not an offset exists
*/
public function offsetExists($offset)
{
return array_key_exists($offset, $this->_links);
}
/**
* ArrayAccess - Unsets an offset
*/
public function offsetUnset($offset)
{
if (!$this->_loggedIn) {
// TODO: raise an exception
die('You are not authorized to delete a link.');
}
$url = $this->_links[$offset]['url'];
unset($this->_urls[$url]);
unset($this->_links[$offset]);
}
/**
* ArrayAccess - Returns the value at specified offset
*/
public function offsetGet($offset)
{
return isset($this->_links[$offset]) ? $this->_links[$offset] : null;
}
/**
* Iterator - Returns the current element
*/
function current()
{
return $this->_links[$this->_keys[$this->_position]];
}
/**
* Iterator - Returns the key of the current element
*/
function key()
{
return $this->_keys[$this->_position];
}
/**
* Iterator - Moves forward to next element
*/
function next()
{
++$this->_position;
}
/**
* Iterator - Rewinds the Iterator to the first element
*
* Entries are sorted by date (latest first)
*/
function rewind()
{
$this->_keys = array_keys($this->_links);
rsort($this->_keys);
$this->_position = 0;
}
/**
* Iterator - Checks if current position is valid
*/
function valid()
{
return isset($this->_keys[$this->_position]);
}
/**
* Checks if the DB directory and file exist
*
* If no DB file is found, creates a dummy DB.
*/
private function _checkDB()
{
if (file_exists($this->_datastore)) {
return;
}
// Create a dummy database for example
$this->_links = array();
$link = array(
'title'=>' Shaarli: the personal, minimalist, super-fast, no-database delicious clone',
'url'=>'https://github.com/shaarli/Shaarli/wiki',
'description'=>'Welcome to Shaarli! This is your first public bookmark. To edit or delete me, you must first login.
To learn how to use Shaarli, consult the link "Help/documentation" at the bottom of this page.
You use the community supported version of the original Shaarli project, by Sebastien Sauvage.',
'private'=>0,
'linkdate'=> date('Ymd_His'),
'tags'=>'opensource software'
);
$this->_links[$link['linkdate']] = $link;
$link = array(
'title'=>'My secret stuff... - Pastebin.com',
'url'=>'http://sebsauvage.net/paste/?8434b27936c09649#bR7XsXhoTiLcqCpQbmOpBi3rq2zzQUC5hBI7ZT1O3x8=',
'description'=>'Shhhh! I\'m a private link only YOU can see. You can delete me too.',
'private'=>1,
'linkdate'=> date('Ymd_His', strtotime('-1 minute')),
'tags'=>'secretstuff'
);
$this->_links[$link['linkdate']] = $link;
// Write database to disk
$this->writeDB();
}
/**
* Reads database from disk to memory
*/
private function _readDB()
{
// Public links are hidden and user not logged in => nothing to show
if ($this->_hidePublicLinks && !$this->_loggedIn) {
$this->_links = array();
return;
}
// Read data
// Note that gzinflate is faster than gzuncompress.
// See: http://www.php.net/manual/en/function.gzdeflate.php#96439
$this->_links = array();
if (file_exists($this->_datastore)) {
$this->_links = unserialize(gzinflate(base64_decode(
substr(file_get_contents($this->_datastore),
strlen(self::$phpPrefix), -strlen(self::$phpSuffix)))));
}
// If user is not logged in, filter private links.
if (!$this->_loggedIn) {
$toremove = array();
foreach ($this->_links as $link) {
if ($link['private'] != 0) {
$toremove[] = $link['linkdate'];
}
}
foreach ($toremove as $linkdate) {
unset($this->_links[$linkdate]);
}
}
$this->_urls = array();
foreach ($this->_links as &$link) {
// Keep the list of the mapping URLs-->linkdate up-to-date.
$this->_urls[$link['url']] = $link['linkdate'];
// Sanitize data fields.
sanitizeLink($link);
// Remove private tags if the user is not logged in.
if (! $this->_loggedIn) {
$link['tags'] = preg_replace('/(^| )\.[^($| )]+/', '', $link['tags']);
}
// Do not use the redirector for internal links (Shaarli note URL starting with a '?').
if (!empty($this->_redirector) && !startsWith($link['url'], '?')) {
$link['real_url'] = $this->_redirector;
if ($this->redirectorEncode) {
$link['real_url'] .= urlencode(unescape($link['url']));
} else {
$link['real_url'] .= $link['url'];
}
}
else {
$link['real_url'] = $link['url'];
}
}
}
/**
* Saves the database from memory to disk
*
* @throws IOException the datastore is not writable
*/
private function writeDB()
{
if (is_file($this->_datastore) && !is_writeable($this->_datastore)) {
// The datastore exists but is not writeable
throw new IOException($this->_datastore);
} else if (!is_file($this->_datastore) && !is_writeable(dirname($this->_datastore))) {
// The datastore does not exist and its parent directory is not writeable
throw new IOException(dirname($this->_datastore));
}
file_put_contents(
$this->_datastore,
self::$phpPrefix.base64_encode(gzdeflate(serialize($this->_links))).self::$phpSuffix
);
}
/**
* Saves the database from memory to disk
*
* @param string $pageCacheDir page cache directory
*/
public function savedb($pageCacheDir)
{
if (!$this->_loggedIn) {
// TODO: raise an Exception instead
die('You are not authorized to change the database.');
}
$this->writeDB();
invalidateCaches($pageCacheDir);
}
/**
* Returns the link for a given URL, or False if it does not exist.
*
* @param string $url URL to search for
*
* @return mixed the existing link if it exists, else 'false'
*/
public function getLinkFromUrl($url)
{
if (isset($this->_urls[$url])) {
return $this->_links[$this->_urls[$url]];
}
return false;
}
/**
* Returns the shaare corresponding to a smallHash.
*
* @param string $request QUERY_STRING server parameter.
*
* @return array $filtered array containing permalink data.
*
* @throws LinkNotFoundException if the smallhash is malformed or doesn't match any link.
*/
public function filterHash($request)
{
$request = substr($request, 0, 6);
$linkFilter = new LinkFilter($this->_links);
return $linkFilter->filter(LinkFilter::$FILTER_HASH, $request);
}
/**
* Returns the list of articles for a given day.
*
* @param string $request day to filter. Format: YYYYMMDD.
*
* @return array list of shaare found.
*/
public function filterDay($request) {
$linkFilter = new LinkFilter($this->_links);
return $linkFilter->filter(LinkFilter::$FILTER_DAY, $request);
}
/**
* Filter links according to search parameters.
*
* @param array $filterRequest Search request content. Supported keys:
* - searchtags: list of tags
* - searchterm: term search
* @param bool $casesensitive Optional: Perform case sensitive filter
* @param bool $privateonly Optional: Returns private links only if true.
*
* @return array filtered links, all links if no suitable filter was provided.
*/
public function filterSearch($filterRequest = array(), $casesensitive = false, $privateonly = false)
{
// Filter link database according to parameters.
$searchtags = !empty($filterRequest['searchtags']) ? escape($filterRequest['searchtags']) : '';
$searchterm = !empty($filterRequest['searchterm']) ? escape($filterRequest['searchterm']) : '';
// Search tags + fullsearch.
if (empty($type) && ! empty($searchtags) && ! empty($searchterm)) {
$type = LinkFilter::$FILTER_TAG | LinkFilter::$FILTER_TEXT;
$request = array($searchtags, $searchterm);
}
// Search by tags.
elseif (! empty($searchtags)) {
$type = LinkFilter::$FILTER_TAG;
$request = $searchtags;
}
// Fulltext search.
elseif (! empty($searchterm)) {
$type = LinkFilter::$FILTER_TEXT;
$request = $searchterm;
}
// Otherwise, display without filtering.
else {
$type = '';
$request = '';
}
$linkFilter = new LinkFilter($this->_links);
return $linkFilter->filter($type, $request, $casesensitive, $privateonly);
}
/**
* Returns the list of all tags
* Output: associative array key=tags, value=0
*/
public function allTags()
{
$tags = array();
foreach ($this->_links as $link) {
foreach (explode(' ', $link['tags']) as $tag) {
if (!empty($tag)) {
$tags[$tag] = (empty($tags[$tag]) ? 1 : $tags[$tag] + 1);
}
}
}
// Sort tags by usage (most used tag first)
arsort($tags);
return $tags;
}
/**
* Returns the list of days containing articles (oldest first)
* Output: An array containing days (in format YYYYMMDD).
*/
public function days()
{
$linkDays = array();
foreach (array_keys($this->_links) as $day) {
$linkDays[substr($day, 0, 8)] = 0;
}
$linkDays = array_keys($linkDays);
sort($linkDays);
return $linkDays;
}
}
