Add a persistent 'shorturl' key to all links

All existing link will keep their permalinks.
New links will have smallhash generated with date+id.

The purpose of this is to avoid collision between links due to their creation date.

7 files changed, 32 insertions, 7 deletions

diff --git a/application/FeedBuilder.php b/application/FeedBuilder.php
index bfdf2fd3..fedd90e6 100644
--- a/application/FeedBuilder.php
+++ b/application/FeedBuilder.php
@@ -143,7 +143,7 @@ class FeedBuilder
      */
     protected function buildItem($link, $pageaddr)
     {
-        $link['guid'] = $pageaddr .'?'. smallHash($link['created']->format('Ymd_His'));
+        $link['guid'] = $pageaddr .'?'. $link['shorturl'];
         // Check for both signs of a note: starting with ? and 7 chars long.
         if ($link['url'][0] === '?' && strlen($link['url']) === 7) {
             $link['url'] = $pageaddr . $link['url'];
diff --git a/application/LinkDB.php b/application/LinkDB.php
index e429ab4f..1e13286a 100644
--- a/application/LinkDB.php
+++ b/application/LinkDB.php
@@ -22,6 +22,7 @@
  *              Can be absolute or relative.
  *              Relative URLs are permalinks (e.g.'?m-ukcw')
  *  - real_url  Absolute processed URL.
+ *  - shorturl  Permalink smallhash
  *
  * Implements 3 interfaces:
  *  - ArrayAccess: behaves like an associative array;
@@ -264,6 +265,7 @@ You use the community supported version of the original Shaarli project, by Seba
             'created'=> new DateTime(),
             'tags'=>'opensource software'
         );
+        $link['shorturl'] = link_small_hash($link['created'], $link['id']);
         $this->links[1] = $link;
 
         $link = array(
@@ -273,8 +275,9 @@ You use the community supported version of the original Shaarli project, by Seba
             'description'=>'Shhhh! I\'m a private link only YOU can see. You can delete me too.',
             'private'=>1,
             'created'=> new DateTime('1 minute ago'),
-            'tags'=>'secretstuff'
+            'tags'=>'secretstuff',
         );
+        $link['shorturl'] = link_small_hash($link['created'], $link['id']);
         $this->links[0] = $link;
 
         // Write database to disk
@@ -335,10 +338,11 @@ You use the community supported version of the original Shaarli project, by Seba
             // To be able to load links before running the update, and prepare the update
             if (! isset($link['created'])) {
                 $link['id'] = $link['linkdate'];
-                $link['created'] = DateTime::createFromFormat('Ymd_His', $link['linkdate']);
+                $link['created'] = DateTime::createFromFormat(self::LINK_DATE_FORMAT, $link['linkdate']);
                 if (! empty($link['updated'])) {
-                    $link['updated'] = DateTime::createFromFormat('Ymd_His', $link['updated']);
+                    $link['updated'] = DateTime::createFromFormat(self::LINK_DATE_FORMAT, $link['updated']);
                 }
+                $link['shorturl'] = smallHash($link['linkdate']);
             }
         }
 
@@ -558,7 +562,7 @@ You use the community supported version of the original Shaarli project, by Seba
      *
      * @param int $id Persistent ID of a link.
      *
-     * @return int Real offset in local array, or null if doesn't exists.
+     * @return int Real offset in local array, or null if doesn't exist.
      */
     protected function getLinkOffset($id)
     {
diff --git a/application/LinkFilter.php b/application/LinkFilter.php
index 7bab46ba..daa6d9cc 100644
--- a/application/LinkFilter.php
+++ b/application/LinkFilter.php
@@ -120,7 +120,7 @@ class LinkFilter
     {
         $filtered = array();
         foreach ($this->links as $key => $l) {
-            if ($smallHash == smallHash($l['created']->format('Ymd_His'))) {
+            if ($smallHash == $l['shorturl']) {
                 // Yes, this is ugly and slow
                 $filtered[$key] = $l;
                 return $filtered;
diff --git a/application/LinkUtils.php b/application/LinkUtils.php
index 9d9ae3cb..cf58f808 100644
--- a/application/LinkUtils.php
+++ b/application/LinkUtils.php
@@ -169,3 +169,16 @@ function space2nbsp($text)
 function format_description($description, $redirector = '', $indexUrl = '') {
     return nl2br(space2nbsp(hashtag_autolink(text2clickable($description, $redirector), $indexUrl)));
 }
+
+/**
+ * Generate a small hash for a link.
+ *
+ * @param DateTime $date Link creation date.
+ * @param int      $id   Link ID.
+ *
+ * @return string the small hash generated from link data.
+ */
+function link_small_hash($date, $id)
+{
+    return smallHash($date->format(LinkDB::LINK_DATE_FORMAT) . $id);
+}
diff --git a/application/NetscapeBookmarkUtils.php b/application/NetscapeBookmarkUtils.php
index 8a939adb..e7148d00 100644
--- a/application/NetscapeBookmarkUtils.php
+++ b/application/NetscapeBookmarkUtils.php
@@ -174,6 +174,7 @@ class NetscapeBookmarkUtils
             $newLinkDate->setTimezone(new DateTimeZone(date_default_timezone_get()));
             $newLink['created'] = $newLinkDate;
             $newLink['id'] = $linkDb->getNextId();
+            $newLink['shorturl'] = link_small_hash($newLink['created'], $newLink['id']);
             $linkDb[$newLink['id']] = $newLink;
             $importCount++;
         }
diff --git a/application/Updater.php b/application/Updater.php
index 16c8c376..f0d02814 100644
--- a/application/Updater.php
+++ b/application/Updater.php
@@ -223,6 +223,9 @@ class Updater
      * Since this update is very sensitve (changing the whole database), the datastore will be
      * automatically backed up into the file datastore.<datetime>.php.
      *
+     * LinkDB also adds the field 'shorturl' with the precedent format (linkdate smallhash),
+     * which will be saved by this method.
+     *
      * @return bool true if the update is successful, false otherwise.
      */
     public function updateMethodDatastoreIds()
diff --git a/application/Utils.php b/application/Utils.php
index 0166ee2a..0a5b476e 100644
--- a/application/Utils.php
+++ b/application/Utils.php
@@ -31,7 +31,11 @@ function logm($logFile, $clientIp, $message)
  *   - are NOT cryptographically secure (they CAN be forged)
  *
  *  In Shaarli, they are used as a tinyurl-like link to individual entries,
- *  e.g. smallHash('20111006_131924') --> yZH23w
+ *  built once with the combination of the date and item ID.
+ *  e.g. smallHash('20111006_131924' . 142) --> eaWxtQ
+ *
+ * @warning before v0.8.1, smallhashes were built only with the date,
+ *          and their value has been preserved.
  *
  * @param string $text Create a hash from this text.
  *