feature 657: permalinks for categories

git-svn-id: http://piwigo.org/svn/trunk@1866 68402e56-0260-453c-a942-63ccdbb3a9ee

22 files changed, 650 insertions, 89 deletions

diff --git a/admin.php b/admin.php
index 9b2147728..9282f3430 100644
--- a/admin.php
+++ b/admin.php
@@ -4,7 +4,6 @@
 // | Copyright (C) 2002-2003 Pierrick LE GALL - pierrick@phpwebgallery.net |
 // | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
 // +-----------------------------------------------------------------------+
-// | branch        : BSF (Best So Far)
 // | file          : $Id$
 // | last update   : $Date$
 // | last modifier : $Author$
@@ -107,10 +106,9 @@ $template->assign_vars(
     'U_THUMBNAILS'=> $link_start.'thumbnail',
     'U_USERS'=> $link_start.'user_list',
     'U_GROUPS'=> $link_start.'group_list',
+    'U_PERMALINKS'=> $link_start.'permalinks',
     'U_RETURN'=> make_index_url(),
     'U_ADMIN'=> PHPWG_ROOT_PATH.'admin.php',
-    'L_ADMIN' => $lang['admin'],
-    'L_ADMIN_HINT' => $lang['hint_admin']
     )
   );
 if ($conf['ws_access_control']) // Do we need to display ws_checker
diff --git a/admin/cat_list.php b/admin/cat_list.php
index c34754f87..e11e13b8b 100644
--- a/admin/cat_list.php
+++ b/admin/cat_list.php
@@ -138,32 +138,6 @@ SELECT id, name
 }
 
 // +-----------------------------------------------------------------------+
-// |                           Cache management                            |
-// +-----------------------------------------------------------------------+
-$query = '
-SELECT *
-  FROM '.CATEGORIES_TABLE;
-if (!isset($_GET['parent_id']))
-{
-  $query.= '
-  WHERE id_uppercat IS NULL';
-}
-else
-{
-  $query.= '
-  WHERE id_uppercat = '.$_GET['parent_id'];
-}
-$query.= '
-  ORDER BY rank ASC
-;';
-$result = pwg_query($query);
-while ($row = mysql_fetch_assoc($result))
-{
-  $categories[$row['rank']] = $row;
-  $categories[$row['rank']]['nb_subcats'] = 0;
-}
-
-// +-----------------------------------------------------------------------+
 // |                            Navigation path                            |
 // +-----------------------------------------------------------------------+
 
@@ -209,7 +183,7 @@ $tpl = array('cat_first','cat_last');
 $categories = array();
 
 $query = '
-SELECT id, name, dir, rank, nb_images, status
+SELECT id, name, permalink, dir, rank, nb_images, status
   FROM '.CATEGORIES_TABLE;
 if (!isset($_GET['parent_id']))
 {
diff --git a/admin/include/functions.php b/admin/include/functions.php
index ff54dbbab..99ebfac62 100644
--- a/admin/include/functions.php
+++ b/admin/include/functions.php
@@ -120,6 +120,11 @@ DELETE FROM '.CATEGORIES_TABLE.'
 ;';
   pwg_query($query);
 
+   $query='
+DELETE FROM '.OLD_PERMALINKS_TABLE.'
+  WHERE cat_id IN ('.implode(',',$cat_ids).')';
+  pwg_query($query);
+
   if (isset($counts['del_categories']))
   {
     $counts['del_categories']+= count($ids);
diff --git a/admin/include/functions_permalinks.php b/admin/include/functions_permalinks.php
new file mode 100644
index 000000000..9a36ccf3d
--- /dev/null
+++ b/admin/include/functions_permalinks.php
@@ -0,0 +1,170 @@
+<?php
+// +-----------------------------------------------------------------------+
+// | PhpWebGallery - a PHP based picture gallery                           |
+// | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
+// +-----------------------------------------------------------------------+
+// | file          : $Id: admin/function_permalinks.inc.php$
+// | last update   : $Date$
+// | last modifier : $Author$
+// | revision      : $Revision$
+// +-----------------------------------------------------------------------+
+// | This program is free software; you can redistribute it and/or modify  |
+// | it under the terms of the GNU General Public License as published by  |
+// | the Free Software Foundation                                          |
+// |                                                                       |
+// | This program is distributed in the hope that it will be useful, but   |
+// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
+// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
+// | General Public License for more details.                              |
+// |                                                                       |
+// | You should have received a copy of the GNU General Public License     |
+// | along with this program; if not, write to the Free Software           |
+// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
+// | USA.                                                                  |
+// +-----------------------------------------------------------------------+
+
+/** deletes the permalink associated with a category
+ * returns true on success
+ * @param int cat_id the target category id
+ * @param boolean save if true, the current category-permalink association
+ * is saved in the old permalinks table in case external links hit it
+ */
+function delete_cat_permalink( $cat_id, $save )
+{
+  global $page, $cache;
+  $query = '
+SELECT permalink
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id="'.$cat_id.'"
+;';
+  $result = pwg_query($query);
+  if ( mysql_num_rows($result) )
+  {
+    list($permalink) = mysql_fetch_array($result);
+  }
+  if ( !isset($permalink) )
+  {// no permalink; nothing to do
+    return true;
+  }
+  if ($save)
+  {
+    $old_cat_id = get_cat_id_from_old_permalink($permalink, false);
+    if ( isset($old_cat_id) and $old_cat_id!=$cat_id )
+    {
+      $page['errors'][] = 
+        sprintf( 
+          l10n('Permalink_%s_histo_used_by_%s'),
+          $permalink, $old_cat_id
+        );
+      return false;
+    }
+  }
+  $query = '
+UPDATE '.CATEGORIES_TABLE.'
+  SET permalink=NULL
+  WHERE id='.$cat_id.'
+  LIMIT 1';
+  pwg_query($query);
+  
+  unset( $cache['cat_names'] ); //force regeneration
+  if ($save)
+  {
+    if ( isset($old_cat_id) )
+    {
+      $query = '
+UPDATE '.OLD_PERMALINKS_TABLE.'
+  SET date_deleted=NOW()
+  WHERE cat_id='.$cat_id.' AND permalink="'.$permalink.'"';
+    }
+    else
+    {
+      $query = '
+INSERT INTO '.OLD_PERMALINKS_TABLE.'
+  (permalink, cat_id, date_deleted)
+VALUES
+  ( "'.$permalink.'",'.$cat_id.',NOW() )';
+    }
+    pwg_query( $query );
+  }
+  return true;
+}
+
+/** sets a new permalink for a category
+ * returns true on success
+ * @param int cat_id the target category id
+ * @param string permalink the new permalink
+ * @param boolean save if true, the current category-permalink association
+ * is saved in the old permalinks table in case external links hit it
+ */
+function set_cat_permalink( $cat_id, $permalink, $save )
+{
+  global $page, $cache;
+  
+  $sanitized_permalink = preg_replace( '#[^a-zA-Z0-9_-]#', '' ,$permalink);
+  if ( $sanitized_permalink != $permalink 
+      or preg_match( '#^(\d)+-?#', $permalink) )
+  {
+    $page['errors'][] = l10n('Permalink_name_rule');
+    return false;
+  }
+  
+  $existing_cat_id = get_cat_id_from_permalink( $permalink );
+  if ( isset($existing_cat_id) )
+  {
+    if ( $existing_cat_id==$cat_id )
+    {// no change required
+      return true;
+    }
+    else
+    {
+      $page['errors'][] = 
+        sprintf( 
+          l10n('Permalink %s is already used by category %s'),
+          $permalink, $existing_cat_id 
+        );
+      return false;
+    }
+  }
+
+  if ($save)
+  {
+    $old_cat_id = get_cat_id_from_old_permalink($permalink, false);
+    if ( isset($old_cat_id) )
+    {
+      if ( $old_cat_id!=$cat_id )
+      {
+        $page['errors'][] = 
+          sprintf( 
+            l10n('Permalink_%s_histo_used_by_%s'),
+            $permalink, $old_cat_id
+          );
+        return false;
+      }
+      else
+      {
+        $query = '
+DELETE FROM '.OLD_PERMALINKS_TABLE.'
+  WHERE cat_id='.$cat_id.' AND permalink="'.$permalink.'"';
+        pwg_query($query);
+      }
+    }
+  }
+  
+  if ( !delete_cat_permalink($cat_id, $save ) )
+  {
+    return false;
+  }
+
+  $query = '
+UPDATE '.CATEGORIES_TABLE.'
+  SET permalink="'.$permalink.'"
+  WHERE id='.$cat_id.'
+  LIMIT 1';
+  pwg_query($query);
+
+  unset( $cache['cat_names'] ); //force regeneration
+  
+  return true;
+}
+
+?>
diff --git a/admin/permalinks.php b/admin/permalinks.php
new file mode 100644
index 000000000..d00770dd9
--- /dev/null
+++ b/admin/permalinks.php
@@ -0,0 +1,97 @@
+<?php
+// +-----------------------------------------------------------------------+
+// | PhpWebGallery - a PHP based picture gallery                           |
+// | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
+// +-----------------------------------------------------------------------+
+// | file          : $Id$
+// | last update   : $Date$
+// | last modifier : $Author$
+// | revision      : $Revision$
+// +-----------------------------------------------------------------------+
+// | This program is free software; you can redistribute it and/or modify  |
+// | it under the terms of the GNU General Public License as published by  |
+// | the Free Software Foundation                                          |
+// |                                                                       |
+// | This program is distributed in the hope that it will be useful, but   |
+// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
+// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
+// | General Public License for more details.                              |
+// |                                                                       |
+// | You should have received a copy of the GNU General Public License     |
+// | along with this program; if not, write to the Free Software           |
+// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
+// | USA.                                                                  |
+// +-----------------------------------------------------------------------+
+
+if (!defined('PHPWG_ROOT_PATH')) die('Hacking attempt!');
+
+include_once(PHPWG_ROOT_PATH.'admin/include/functions_permalinks.php');
+
+$selected_cat = array();
+if ( isset($_POST['set_permalink']) and $_POST['cat_id']>0 )
+{
+  $permalink = $_POST['permalink'];
+  if ( empty($permalink) )
+    delete_cat_permalink($_POST['cat_id'], isset($_POST['save']) );
+  else
+    set_cat_permalink($_POST['cat_id'], $permalink, isset($_POST['save']) );
+  $selected_cat = array( $_POST['cat_id'] );
+}
+elseif ( isset($_GET['delete_permanent']) )
+{
+  $query = '
+DELETE FROM '.OLD_PERMALINKS_TABLE.'
+  WHERE permalink="'.$_GET['delete_permanent'].'"
+  LIMIT 1';
+  pwg_query($query);
+  if (mysql_affected_rows()==0)
+    array_push($page['errors'], 'Cannot delete the old permalink !');
+}
+
+$template->set_filename('permalinks', 'admin/permalinks.tpl' );
+
+$query = '
+SELECT 
+  id, 
+  CONCAT(id, " - ", name, IF(permalink IS NULL, "", " &radic;") ) AS name,
+  uppercats, global_rank 
+FROM '.CATEGORIES_TABLE;
+
+display_select_cat_wrapper( $query, $selected_cat, 'categories', false );
+
+$query = '
+SELECT id, name, permalink 
+  FROM '.CATEGORIES_TABLE.'
+  WHERE permalink IS NOT NULL';
+$result=pwg_query($query);
+while ( $row=mysql_fetch_assoc($result) )
+{
+  $display_name = get_cat_display_name( array($row) );
+  $template->assign_block_vars( 'permalink',
+    array(
+      'CAT_ID' => $row['id'],
+      'CAT' => $display_name,
+      'PERMALINK' => $row['permalink'],
+    )
+    );
+}
+
+$url_del_base = get_root_url().'admin.php?page=permalinks';
+
+$query = 'SELECT * FROM '.OLD_PERMALINKS_TABLE;
+$result = pwg_query($query);
+while ( $row=mysql_fetch_assoc($result) )
+{
+  $row['display_name'] = get_cat_display_name_cache($row['cat_id']);
+  $row['U_DELETE'] =
+      add_url_params(
+        $url_del_base,
+        array( 'delete_permanent'=> $row['permalink'] )
+      );
+  $template->assign_block_vars( 'deleted_permalink', $row );
+}
+
+$template->assign_var('U_HELP', get_root_url().'popuphelp.php?page=permalinks');
+
+$template->assign_var_from_handle('ADMIN_CONTENT', 'permalinks');
+?>
diff --git a/admin/plugin.php b/admin/plugin.php
index 1657f10c8..aa8faaade 100644
--- a/admin/plugin.php
+++ b/admin/plugin.php
@@ -49,8 +49,7 @@ if (count($sections)<2)
 }
 
 $plugin_id = $sections[0];
-$check_db_plugin = get_db_plugins('active', $plugin_id );
-if (empty($check_db_plugin))
+if ( !isset($pwg_loaded_plugins[$plugin_id]) )
 {
   die('Invalid URL - plugin '.$plugin_id.' not active');
 }
diff --git a/comments.php b/comments.php
index 9a41dcb2b..b46ee3f8e 100644
--- a/comments.php
+++ b/comments.php
@@ -369,17 +369,12 @@ SELECT id, name, file, path, tn_ext
   }
 
   // retrieving category informations
-  $categories = array();
   $query = '
-SELECT id, name, uppercats
+SELECT id, name, permalink, uppercats
   FROM '.CATEGORIES_TABLE.'
   WHERE id IN ('.implode(',', $category_ids).')
 ;';
-  $result = pwg_query($query);
-  while ($row = mysql_fetch_assoc($result))
-  {
-    $categories[$row['id']] = $row;
-  }
+  $categories = hash_from_query($query, 'id');
 
   foreach ($comments as $comment)
   {
diff --git a/include/category_cats.inc.php b/include/category_cats.inc.php
index e9549ba44..ccdfa5949 100644
--- a/include/category_cats.inc.php
+++ b/include/category_cats.inc.php
@@ -35,7 +35,7 @@ if ($page['section']=='recent_cats')
   // $user['forbidden_categories'] including with USER_CACHE_CATEGORIES_TABLE
   $query = '
 SELECT
-  id, name, representative_picture_id, comment, nb_images, uppercats,
+  id, name, permalink, representative_picture_id, comment, nb_images, uppercats,
   date_last, max_date_last, count_images, count_categories, global_rank
   FROM '.CATEGORIES_TABLE.' INNER JOIN '.USER_CACHE_CATEGORIES_TABLE.'
   ON id = cat_id and user_id = '.$user['id'].'
@@ -57,7 +57,7 @@ else
   // $user['forbidden_categories'] including with USER_CACHE_CATEGORIES_TABLE
   $query = '
 SELECT
-  id, name, representative_picture_id, comment, nb_images,
+  id, name, permalink, representative_picture_id, comment, nb_images,
   date_last, max_date_last, count_images, count_categories
   FROM '.CATEGORIES_TABLE.' INNER JOIN '.USER_CACHE_CATEGORIES_TABLE.'
   ON id = cat_id and user_id = '.$user['id'].'
diff --git a/include/constants.php b/include/constants.php
index 0d1b6f9ae..f442bac99 100644
--- a/include/constants.php
+++ b/include/constants.php
@@ -4,8 +4,7 @@
 // | Copyright (C) 2002-2003 Pierrick LE GALL - pierrick@phpwebgallery.net |
 // | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
 // +-----------------------------------------------------------------------+
-// | branch        : BSF (Best So Far)
-// | file          : $RCSfile$
+// | file          : $Id$
 // | last update   : $Date$
 // | last modifier : $Author$
 // | revision      : $Revision$
@@ -75,4 +74,5 @@ define('TAGS_TABLE', $prefixeTable.'tags');
 define('IMAGE_TAG_TABLE', $prefixeTable.'image_tag');
 define('PLUGINS_TABLE', $prefixeTable.'plugins');
 define('WEB_SERVICES_ACCESS_TABLE', $prefixeTable.'ws_access');
+define('OLD_PERMALINKS_TABLE', $prefixeTable.'old_permalinks');
 ?>
diff --git a/include/functions.inc.php b/include/functions.inc.php
index 6b44c81dc..eb706e6ba 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -1175,6 +1175,26 @@ function simple_hash_from_query($query, $keyname, $valuename)
 }
 
 /**
+ * creates an hashed based on a query, this function is a very common
+ * pattern used here. The key is given as parameter, the value is an associative
+ * array.
+ *
+ * @param string $query
+ * @param string $keyname
+ * @return array
+ */
+function hash_from_query($query, $keyname)
+{
+  $array = array();
+  $result = pwg_query($query);
+  while ($row = mysql_fetch_assoc($result))
+  {
+    $array[ $row[$keyname] ] = $row;
+  }
+  return $array;
+}
+
+/**
  * Return basename of the current script
  * Lower case convertion is applied on return value
  * Return value is without file extention ".php"
diff --git a/include/functions_category.inc.php b/include/functions_category.inc.php
index 66b8865da..5d1679e5c 100644
--- a/include/functions_category.inc.php
+++ b/include/functions_category.inc.php
@@ -59,7 +59,7 @@ function get_categories_menu()
 SELECT ';
   // From CATEGORIES_TABLE
   $query.= '
-  name, id, nb_images, global_rank,';
+  id, name, permalink, nb_images, global_rank,';
   // From USER_CACHE_CATEGORIES_TABLE
   $query.= '
   date_last, max_date_last, count_images, count_categories';
@@ -159,25 +159,34 @@ SELECT *
     $cat['comment'] = nl2br(@$cat['comment']);
   }
 
-  $names = array();
-  $query = '
-SELECT id, name
-  FROM '.CATEGORIES_TABLE.'
-  WHERE id IN ('.$cat['uppercats'].')
-;';
-  $result = pwg_query($query);
-  while($row = mysql_fetch_assoc($result))
-  {
-    $names[$row['id']] = $row;
+  $upper_ids = explode(',', $cat['uppercats']);
+  if ( count($upper_ids)==1 )
+  {// no need to make a query for level 1
+    $cat['upper_names'] = array(
+        array(
+          'id' => $cat['id'],
+          'name' => $cat['name'],
+          'permalink' => $cat['permalink'],
+          )
+      );
   }
-
-  // category names must be in the same order than uppercats list
-  $cat['upper_names'] = array();
-  foreach (explode(',', $cat['uppercats']) as $cat_id)
+  else
   {
-    $cat['upper_names'][$cat_id] = $names[$cat_id];
+    $names = array();
+    $query = '
+  SELECT id, name, permalink
+    FROM '.CATEGORIES_TABLE.'
+    WHERE id IN ('.$cat['uppercats'].')
+  ;';
+    $names = hash_from_query($query, 'id');
+
+    // category names must be in the same order than uppercats list
+    $cat['upper_names'] = array();
+    foreach ($upper_ids as $cat_id)
+    {
+      array_push( $cat['upper_names'], $names[$cat_id]);
+    }
   }
-
   return $cat;
 }
 
@@ -308,7 +317,7 @@ function display_select_cat_wrapper($query, $selecteds, $blockname,
   $categories = array();
   if (!empty($result))
   {
-    while ($row = mysql_fetch_array($result))
+    while ($row = mysql_fetch_assoc($result))
     {
       array_push($categories, $row);
     }
@@ -355,6 +364,50 @@ SELECT DISTINCT(id)
   return $subcats;
 }
 
+/** returns a category id that corresponds to the given permalink (or null)
+ * @param string permalink
+ */
+function get_cat_id_from_permalink( $permalink )
+{
+  $query ='
+SELECT id FROM '.CATEGORIES_TABLE.'
+  WHERE permalink="'.$permalink.'"';
+  $ids = array_from_query($query, 'id');
+  if (!empty($ids))
+  {
+    return $ids[0];
+  }
+  return null;
+}
+
+/** returns a category id that has used before this permalink (or null)
+ * @param string permalink
+ * @param boolean is_hit if true update the usage counters on the old permalinks
+ */
+function get_cat_id_from_old_permalink($permalink, $is_hit)
+{
+  $query='
+SELECT c.id
+  FROM '.OLD_PERMALINKS_TABLE.' op INNER JOIN '.CATEGORIES_TABLE.' c
+    ON op.cat_id=c.id
+  WHERE op.permalink="'.$permalink.'"
+  LIMIT 1';
+  $result = pwg_query($query);
+  $cat_id = null;
+  if ( mysql_num_rows($result) )
+    list( $cat_id ) = mysql_fetch_array($result);
+
+  if ( isset($cat_id) and $is_hit )
+  {
+    $query='
+UPDATE '.OLD_PERMALINKS_TABLE.' SET last_hit=NOW(), hit=hit+1
+  WHERE permalink="'.$permalink.'" AND cat_id='.$cat_id.'
+  LIMIT 1';
+    pwg_query($query);
+  }
+  return $cat_id;
+}
+
 function global_rank_compare($a, $b)
 {
   return strnatcasecmp($a['global_rank'], $b['global_rank']);
diff --git a/include/functions_html.inc.php b/include/functions_html.inc.php
index dcb42cdb1..5612454b0 100644
--- a/include/functions_html.inc.php
+++ b/include/functions_html.inc.php
@@ -234,8 +234,8 @@ function create_navigation_bar(
  * returns the list of categories as a HTML string
  *
  * categories string returned contains categories as given in the input
- * array $cat_informations. $cat_informations array must be an association
- * of {category_id => array( id, name) }. If url input parameter is null,
+ * array $cat_informations. $cat_informations array must be an array
+ * of array( id=>?, name=>?, permalink=>?). If url input parameter is null,
  * returns only the categories name without links.
  *
  * @param array cat_informations
@@ -251,10 +251,10 @@ function get_cat_display_name($cat_informations,
 
   $output = '';
   $is_first = true;
-  foreach ($cat_informations as $id => $cat)
+  foreach ($cat_informations as $cat)
   {
     is_array($cat) or trigger_error(
-        'get_cat_display_name wrong type for cat '.$id, E_USER_WARNING
+        'get_cat_display_name wrong type for category ', E_USER_WARNING
       );
     if ($is_first)
     {
@@ -282,7 +282,7 @@ function get_cat_display_name($cat_informations,
     }
     else
     {
-      $output.= '<a href="'.PHPWG_ROOT_PATH.$url.$id.'">';
+      $output.= '<a href="'.PHPWG_ROOT_PATH.$url.$cat['id'].'">';
       $output.= $cat['name'].'</a>';
     }
   }
@@ -318,14 +318,10 @@ function get_cat_display_name_cache($uppercats,
   if (!isset($cache['cat_names']))
   {
     $query = '
-SELECT id, name
+SELECT id, name, permalink
   FROM '.CATEGORIES_TABLE.'
 ;';
-    $result = pwg_query($query);
-    while ($row = mysql_fetch_assoc($result))
-    {
-      $cache['cat_names'][$row['id']] = $row;
-    }
+    $cache['cat_names'] = hash_from_query($query, 'id');
   }
 
   $output = '';
diff --git a/include/functions_url.inc.php b/include/functions_url.inc.php
index b96ed82b7..04e0b32d1 100644
--- a/include/functions_url.inc.php
+++ b/include/functions_url.inc.php
@@ -336,10 +336,22 @@ function make_section_in_url($params)
             'make_section_in_url category name not set', E_USER_WARNING
             );
 
-        $section_string.= '/category/'.$params['category']['id'];
-        if ( $conf['category_url_style']=='id-name' )
+        array_key_exists('permalink', $params['category']) or trigger_error(
+            'make_section_in_url category permalink not set', E_USER_WARNING
+            );
+
+        $section_string.= '/category/';
+        if ( empty($params['category']['permalink']) )
+        {
+          $section_string.= $params['category']['id'];
+          if ( $conf['category_url_style']=='id-name' )
+          {
+            $section_string.= '-'.str2url($params['category']['name']);
+          }
+        }
+        else
         {
-          $section_string.= '-'.str2url($params['category']['name']);
+          $section_string.= $params['category']['permalink'];
         }
       }
 
diff --git a/include/section_init.inc.php b/include/section_init.inc.php
index 4434ec542..af633571a 100644
--- a/include/section_init.inc.php
+++ b/include/section_init.inc.php
@@ -107,7 +107,6 @@ if (script_basename() == 'picture') // basename without file extention
       {
         $page['image_file'] = $matches[2];
       }
-
     }
     else
     {
@@ -128,11 +127,39 @@ if (0 === strpos(@$tokens[$next_token], 'categor'))
   $page['section'] = 'categories';
   $next_token++;
 
-  if (isset($tokens[$next_token])
-      and preg_match('/^(\d+)/', $tokens[$next_token], $matches))
+  if (isset($tokens[$next_token]) )
   {
-    $page['category'] = $matches[1];
-    $next_token++;
+    if (preg_match('/^(\d+)(?:-(.+))?$/', $tokens[$next_token], $matches))
+    {
+      if ( isset($matches[2]) )
+        $page['hit_by']['cat_url_name'] = $matches[2];
+      $page['category'] = $matches[1];
+      $next_token++;
+    }
+    else
+    {
+      if ( strpos($tokens[$next_token], 'created-')!==0
+          and strpos($tokens[$next_token], 'posted-')!==0
+          and $tokens[$next_token] != 'flat')
+      {// try a permalink
+        $cat_id = get_cat_id_from_permalink($tokens[$next_token]);
+        if ( !isset($cat_id) )
+        {//try old permalink
+          $cat_id = get_cat_id_from_old_permalink($tokens[$next_token], true);
+        }
+        if ( isset($cat_id) )
+        {
+          $page['category'] = $cat_id;
+          $page['hit_by']['cat_permalink'] = $tokens[$next_token];
+        }
+        else
+        {
+          page_not_found('Permalink for album not found');
+        }
+        unset($cat_id);
+        $next_token++;
+      }
+    }
   }
 }
 else if (0 === strpos(@$tokens[$next_token], 'tag'))
@@ -690,5 +717,41 @@ if ( $filter['enabled'] )
   $page['meta_robots']['noindex']=1;
 }
 
+// see if we need a redirect because of a permalink
+if ( 'categories'==$page['section'] and isset($page['category']) )
+{
+  $need_redirect=false;
+  if ( empty($page['category']['permalink']) )
+  {
+    if ( $conf['category_url_style'] == 'id-name' and
+        @$page['hit_by']['cat_url_name'] !== str2url($page['category']['name']) )
+    {
+      $need_redirect=true;
+    }
+  }
+  else
+  {
+    if ( $page['category']['permalink'] !== @$page['hit_by']['cat_permalink'] )
+    {
+      $need_redirect=true;
+    }
+  }
+
+  if ($need_redirect)
+  {
+    $redirect_url = ( script_basename()=='picture'
+        ? duplicate_picture_url()
+          : duplicate_index_url()
+      );
+    if (!headers_sent())
+    { // this is a permanent redirection
+      set_status_header(302);
+      redirect_http( $redirect_url );
+    }
+    redirect( $redirect_url );
+  }
+  unset( $need_redirect, $page['hit_by'] );
+}
+
 trigger_action('loc_end_section_init');
 ?>
\ No newline at end of file
diff --git a/include/ws_functions.inc.php b/include/ws_functions.inc.php
index c8e2a0fe0..f6653a457 100644
--- a/include/ws_functions.inc.php
+++ b/include/ws_functions.inc.php
@@ -319,7 +319,7 @@ function ws_categories_getImages($params, &$service)
   $where_clauses[] = 'id NOT IN ('.$user['forbidden_categories'].')';
 
   $query = '
-SELECT id, name, image_order
+SELECT id, name, permalink, image_order
   FROM '.CATEGORIES_TABLE.'
   WHERE '. implode('
     AND ', $where_clauses);
@@ -465,7 +465,7 @@ function ws_categories_getList($params, &$service)
   }
 
   $query = '
-SELECT id, name, uppercats, global_rank,
+SELECT id, name, permalink, uppercats, global_rank,
     nb_images, count_images AS total_nb_images,
     date_last, max_date_last, count_categories AS nb_categories
   FROM '.CATEGORIES_TABLE.'
@@ -596,7 +596,7 @@ LIMIT 1;';
 
   //-------------------------------------------------------- related categories
   $query = '
-SELECT id, name, uppercats, global_rank, commentable
+SELECT id, name, permalink, uppercats, global_rank, commentable
   FROM '.IMAGE_CATEGORY_TABLE.'
     INNER JOIN '.CATEGORIES_TABLE.' ON category_id = id
   WHERE image_id = '.$image_row['id'].'
diff --git a/install/db/54-database.php b/install/db/54-database.php
new file mode 100644
index 000000000..5014df0e0
--- /dev/null
+++ b/install/db/54-database.php
@@ -0,0 +1,71 @@
+<?php
+// +-----------------------------------------------------------------------+
+// | PhpWebGallery - a PHP based picture gallery                           |
+// | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
+// +-----------------------------------------------------------------------+
+// | file          : $Id$
+// | last update   : $Date$
+// | last modifier : $Author$
+// | revision      : $Revision$
+// +-----------------------------------------------------------------------+
+// | This program is free software; you can redistribute it and/or modify  |
+// | it under the terms of the GNU General Public License as published by  |
+// | the Free Software Foundation                                          |
+// |                                                                       |
+// | This program is distributed in the hope that it will be useful, but   |
+// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
+// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
+// | General Public License for more details.                              |
+// |                                                                       |
+// | You should have received a copy of the GNU General Public License     |
+// | along with this program; if not, write to the Free Software           |
+// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
+// | USA.                                                                  |
+// +-----------------------------------------------------------------------+
+
+if (!defined('PHPWG_ROOT_PATH'))
+{
+  die('Hacking attempt!');
+}
+
+$upgrade_description = 'add column #categories.permalink and table #old_permalinks';
+
+include_once(PHPWG_ROOT_PATH.'include/constants.php');
+
+// +-----------------------------------------------------------------------+
+// |                            Upgrade content                            |
+// +-----------------------------------------------------------------------+
+
+defined('OLD_PERMALINKS_TABLE') or die('OLD_PERMALINKS_TABLE is not defined');
+
+$query = "
+CREATE TABLE `".OLD_PERMALINKS_TABLE."` (
+  `cat_id` smallint(5) unsigned NOT NULL,
+  `permalink` VARCHAR(64) NOT NULL,
+  `date_deleted` datetime NOT NULL,
+  `last_hit` datetime default NULL,
+  `hit` int(10) unsigned NOT NULL default '0',
+  PRIMARY KEY (`permalink`)
+) TYPE=MyISAM
+;";
+pwg_query($query);
+
+$query = "
+ALTER TABLE `".CATEGORIES_TABLE."`
+  ADD COLUMN `permalink` VARCHAR(64) default NULL
+;";
+pwg_query($query);
+
+$query = "
+ALTER TABLE `".CATEGORIES_TABLE."`
+  ADD UNIQUE INDEX `categories_i3` (`permalink`)
+;";
+pwg_query($query);
+
+echo
+"\n"
+.'"'.$upgrade_description.'"'.' ended'
+."\n"
+;
+
+?>
diff --git a/install/phpwebgallery_structure.sql b/install/phpwebgallery_structure.sql
index bc229dc6a..5a9d3e544 100644
--- a/install/phpwebgallery_structure.sql
+++ b/install/phpwebgallery_structure.sql
@@ -38,8 +38,10 @@ CREATE TABLE `phpwebgallery_categories` (
   `commentable` enum('true','false') NOT NULL default 'true',
   `global_rank` varchar(255) default NULL,
   `image_order` varchar(128) default NULL,
+  `permalink` VARCHAR(64) default NULL,
   PRIMARY KEY  (`id`),
-  KEY `categories_i2` (`id_uppercat`)
+  KEY `categories_i2` (`id_uppercat`),
+  UNIQUE KEY `categories_i3` (`permalink`)
 ) TYPE=MyISAM;
 
 --
@@ -203,6 +205,20 @@ CREATE TABLE `phpwebgallery_images` (
 ) TYPE=MyISAM;
 
 --
+-- Table structure for table `phpwebgallery_old_permalinks`
+--
+
+DROP TABLE IF EXISTS `phpwebgallery_old_permalinks`;
+CREATE TABLE `phpwebgallery_old_permalinks` (
+  `cat_id` smallint(5) unsigned NOT NULL,
+  `permalink` VARCHAR(64) NOT NULL,
+  `date_deleted` datetime NOT NULL,
+  `last_hit` datetime default NULL,
+  `hit` int(10) unsigned NOT NULL default '0',
+  PRIMARY KEY (`permalink`)
+) TYPE=MyISAM;
+
+--
 -- Table structure for table `phpwebgallery_plugins`
 --
 
diff --git a/language/en_UK.iso-8859-1/admin.lang.php b/language/en_UK.iso-8859-1/admin.lang.php
index 859ab6719..0dcb19ed0 100644
--- a/language/en_UK.iso-8859-1/admin.lang.php
+++ b/language/en_UK.iso-8859-1/admin.lang.php
@@ -4,8 +4,7 @@
 // | Copyright (C) 2002-2003 Pierrick LE GALL - pierrick@phpwebgallery.net |
 // | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
 // +-----------------------------------------------------------------------+
-// | branch        : BSF (Best So Far)
-// | file          : $RCSfile$
+// | file          : $Id$
 // | last update   : $Date$
 // | last modifier : $Author$
 // | revision      : $Revision$
@@ -43,6 +42,7 @@ $lang['%d waiting pictures validated'] = '%d waiting pictures validated';
 $lang['A new version of PhpWebGallery is available.'] = 'A new version of PhpWebGallery is available.';
 $lang['Actions'] = 'Actions';
 $lang['Activate'] = 'Activate';
+$lang['Add/delete a permalink'] = 'Add/delete a permalink';
 $lang['Add a tag'] = 'Add a tag';
 $lang['Add a user'] = 'Add a user';
 $lang['Add group'] = 'Add group';
@@ -137,6 +137,12 @@ $lang['Other private categories'] = 'Other private categories';
 $lang['Page banner'] = 'Page banner';
 $lang['Parent category'] = 'Parent category';
 $lang['Path'] = 'Path';
+$lang['Permalink'] = 'Permalink';
+$lang['Permalink_%s_histo_used_by_%s'] = 'Permalink %s has been previously used by category %s. Delete from the permalink history first';
+$lang['Permalink_name_rule'] = 'The permalink name must be composed of a-z, A-Z, 0-9, "-" or "_". It must not be numeric or start with number followed by "-"';
+$lang['Permalink %s is already used by category %s'] = 'Permalink %s is already used by category %s';
+$lang['Permalink history'] = 'Permalink history';
+$lang['Permalinks'] = 'Permalinks';
 $lang['Permission denied'] = 'Permission denied';
 $lang['Permission granted thanks to a group'] = 'Permission granted thanks to a group';
 $lang['Permission granted'] = 'Permission granted';
@@ -159,6 +165,7 @@ $lang['Representation of categories'] = 'Representation of categories';
 $lang['Representative'] = 'Representative';
 $lang['Represents'] = 'Represents';
 $lang['Save order'] = 'Save order';
+$lang['Save to permalink history'] = 'Save to permalink history';
 $lang['Select at least one category'] = 'Select at least one category';
 $lang['Select at least one picture'] = 'Select at least one picture';
 $lang['Select at least one user'] = 'Select at least one user';
diff --git a/language/fr_FR.iso-8859-1/admin.lang.php b/language/fr_FR.iso-8859-1/admin.lang.php
index ee335985e..49fd6a98c 100644
--- a/language/fr_FR.iso-8859-1/admin.lang.php
+++ b/language/fr_FR.iso-8859-1/admin.lang.php
@@ -4,8 +4,7 @@
 // | Copyright (C) 2002-2003 Pierrick LE GALL - pierrick@phpwebgallery.net |
 // | Copyright (C) 2003-2007 PhpWebGallery Team - http://phpwebgallery.net |
 // +-----------------------------------------------------------------------+
-// | branch        : BSF (Best So Far)
-// | file          : $RCSfile$
+// | file          : $Id$
 // | last update   : $Date$
 // | last modifier : $Author$
 // | revision      : $Revision$
@@ -43,6 +42,7 @@ $lang['%d waiting pictures validated'] = '%d images en attente validées';
 $lang['A new version of PhpWebGallery is available.'] = 'Une nouvelle version de PhpWebGallery est disponible.';
 $lang['Actions'] = 'Actions';
 $lang['Activate'] = 'Activer';
+$lang['Add/delete a permalink'] = 'Ajouter/effacer un lien permanent';
 $lang['Add a tag'] = 'Ajouter un tag';
 $lang['Add a user'] = 'Ajouter un utilisateur';
 $lang['Add group'] = 'Ajouter un groupe';
@@ -137,6 +137,12 @@ $lang['Other private categories'] = 'Autres catégories privées';
 $lang['Page banner'] = 'Bannière des pages';
 $lang['Parent category'] = 'Catégorie parente';
 $lang['Path'] = 'Chemin';
+$lang['Permalink'] = 'Lien permanent';
+$lang['Permalink_%s_histo_used_by_%s'] = 'Le lien permanent %s a été utilisé précédemment par la catégorie %s. Veuillez l\'effacer de l\'historique des liens permanents';
+$lang['Permalink_name_rule'] = 'Le lien permanent ne doit contenir des caractères que parmi "a-zA-Z0-9", "-" ou "_". Il ne doit pas être numérique ou commencer par un nombre suivi par "-"';
+$lang['Permalink %s is already used by category %s'] = 'Le lien permanent %s est dèja utilisé par la catégorie %s';
+$lang['Permalink history'] = 'Historique des liens permanents';
+$lang['Permalinks'] = 'Liens permanents';
 $lang['Permission denied'] = 'Accès interdit';
 $lang['Permission granted thanks to a group'] = 'Accès autorisé grâce à l\'appartenance aux groupes';
 $lang['Permission granted'] = 'Accès autorisé';
@@ -159,6 +165,7 @@ $lang['Representation of categories'] = 'Représentation des catégories';
 $lang['Representative'] = 'Représentant';
 $lang['Represents'] = 'Représente';
 $lang['Save order'] = 'Sauvegarder l\'ordre';
+$lang['Save to permalink history'] = 'Sauvegarder dans l\'historique des liens permanents';
 $lang['Select at least one category'] = 'Sélectionner au moins une catégorie';
 $lang['Select at least one picture'] = 'Sélectionner au moins une image';
 $lang['Select at least one user'] = 'Sélectionner au moins un utilisateur';
diff --git a/template/yoga/admin.tpl b/template/yoga/admin.tpl
index fdbd50614..5920f4e95 100644
--- a/template/yoga/admin.tpl
+++ b/template/yoga/admin.tpl
@@ -6,7 +6,7 @@
       <ul>
         <li><a href="{U_RETURN}">{lang:home}</a></li>
         <li><a href="{U_FAQ}">{lang:instructions}</a></li>
-        <li><a href="{U_ADMIN}" title="{L_ADMIN_HINT}">{L_ADMIN}</a></li>
+        <li><a href="{U_ADMIN}" title="{lang:hint_admin}">{lang:admin}</a></li>
       </ul>
     </dd>
   </dl>
@@ -34,6 +34,7 @@
         <!-- BEGIN representative -->
         <li><a href="{representative.URL}">{lang:Representative}</a></li>
         <!-- END representative -->
+        <li><a href="{U_PERMALINKS}">{lang:Permalinks}</a></li>
       </ul>
     </dd>
   </dl>
diff --git a/template/yoga/admin/permalinks.tpl b/template/yoga/admin/permalinks.tpl
new file mode 100644
index 000000000..508cf66a9
--- /dev/null
+++ b/template/yoga/admin/permalinks.tpl
@@ -0,0 +1,71 @@
+<div class="titrePage">
+  <ul class="categoryActions">
+    <li><a href="{U_HELP}" onclick="popuphelp(this.href); return false;" title="{lang:Help}"><img src="{themeconf:icon_dir}/help.png" class="button" alt="(?)"></a></li>
+  </ul>
+  <h2>{lang:Permalinks}</h2>
+</div>
+
+<form method="post">
+<fieldset><legend>{lang:Add/delete a permalink}</legend>
+  <label>Category:
+    <select name="cat_id">
+      <option value="0">------</option>
+<!-- BEGIN categories -->
+      <option value="{categories.VALUE}" {categories.SELECTED}>{categories.OPTION}</option>
+<!-- END categories -->
+    </select>
+  </label>
+
+  <label>{lang:Permalink}:
+    <input name="permalink" />
+  </label>
+
+  <label>{lang:Save to permalink history}:
+    <input type="checkbox" name="save" checked="checked" />
+  </label>
+
+  <p>
+    <input type="submit" class="submit" name="set_permalink" value="{lang:submit}"/>
+  </p>
+  </fieldset>
+</form>
+
+<h3>{lang:Permalinks}</h3>
+<table class="table2">
+  <tr class="throw">
+    <td>Id</td>
+    <td>{lang:Category}</td>
+    <td>{lang:Permalink}</td>
+  </tr>
+<!-- BEGIN permalink -->
+  <tr>
+    <td>{permalink.CAT_ID}</td>
+    <td>{permalink.CAT}</td>
+    <td>{permalink.PERMALINK}</td>
+  </tr>
+<!-- END permalink -->
+</table>
+
+<h3>{lang:Permalink history}</h3>
+<table class="table2">
+  <tr class="throw">
+    <td>Id</td>
+    <td>{lang:Category}</td>
+    <td>{lang:Permalink}</td>
+    <td>Deleted on</td>
+    <td>Last hit</td>
+    <td>Hit</td>
+    <td></td>
+  </tr>
+<!-- BEGIN deleted_permalink -->
+  <tr>
+    <td>{deleted_permalink.cat_id}</td>
+    <td>{deleted_permalink.display_name}</td>
+    <td>{deleted_permalink.permalink}</td>
+    <td>{deleted_permalink.date_deleted}</td>
+    <td>{deleted_permalink.last_hit}</td>
+    <td>{deleted_permalink.hit}</td>
+    <td><a href="{deleted_permalink.U_DELETE}"><img src="{pwg_root}{themeconf:icon_dir}/delete.png" alt="Delete"></a></td>
+  </tr>
+<!-- END deleted_permalink -->
+</table>
diff --git a/template/yoga/default-layout.css b/template/yoga/default-layout.css
index 647f27781..2b43bc5bc 100644
--- a/template/yoga/default-layout.css
+++ b/template/yoga/default-layout.css
@@ -80,6 +80,12 @@ FORM P {
 	margin-top: 2em;
 	margin-bottom: 2em;
 }
+
+FORM FIELDSET P {
+	margin-top: 1em;
+	margin-bottom: 0;
+}
+
 .small {
 	font-size: 80%;
 }