Cleanup

functions/addressbook.php

@@ -11,484 +11,504 @@
  * $Id$
  */
 
-/*****************************************************************/
-/*** THIS FILE NEEDS TO HAVE ITS FORMATTING FIXED!!!           ***/
-/*** PLEASE DO SO AND REMOVE THIS COMMENT SECTION.             ***/
-/***    + Base level indent should begin at left margin, as    ***/
-/***      the require_once below looks.                        ***/
-/***    + All identation should consist of four space blocks   ***/
-/***    + Tab characters are evil.                             ***/
-/***    + all comments should use "slash-star ... star-slash"  ***/
-/***      style -- no pound characters, no slash-slash style   ***/
-/***    + FLOW CONTROL STATEMENTS (if, while, etc) SHOULD      ***/
-/***      ALWAYS USE { AND } CHARACTERS!!!                     ***/
-/***    + Please use ' instead of ", when possible. Note "     ***/
-/***      should always be used in _( ) function calls.        ***/
-/*** Thank you for your help making the SM code more readable. ***/
-/*****************************************************************/
-
-// This is the path to the global site-wide addressbook.
-// It looks and feels just like a user's .abook file
-// If this is in the data directory, use "$data_dir/global.abook"
-// If not, specify the path as though it was accessed from the
-// src/ directory ("../global.abook" -> in main directory)
-//
-// If you don't want a global site-wide addressbook, comment these
-// two lines out.  (They are disabled by default.)
-//
-// The global addressbook is unmodifiable by anyone.  You must actually
-// use a shell script or whatnot to modify the contents.
-//
-//global $data_dir;
-//$address_book_global_filename = "$data_dir/global.abook";
-
-// Include backends here.
+/*
+   This is the path to the global site-wide addressbook.
+   It looks and feels just like a user's .abook file
+   If this is in the data directory, use "$data_dir/global.abook"
+   If not, specify the path as though it was accessed from the
+   src/ directory ("../global.abook" -> in main directory)
+
+   If you don't want a global site-wide addressbook, comment these
+   two lines out.  (They are disabled by default.)
+
+   The global addressbook is unmodifiable by anyone.  You must actually
+   use a shell script or whatnot to modify the contents.
+
+  global $data_dir;
+  $address_book_global_filename = "$data_dir/global.abook";
+
+  Include backends here.
+*/
+
 require_once('../functions/abook_local_file.php');
 require_once('../functions/abook_ldap_server.php');
 
-   // Use this if you wanna have a global address book
-   if (isset($address_book_global_filename))
-      include_once('../functions/abook_global_file.php');
-
-   // Only load database backend if database is configured
-   global $addrbook_dsn;
-   if(isset($addrbook_dsn))
-      include_once('../functions/abook_database.php');
-
-
-   // Create and initialize an addressbook object. 
-   // Returns the created object
-   function addressbook_init($showerr = true, $onlylocal = false) {
-      global $data_dir, $username, $ldap_server, $address_book_global_filename;
-      global $addrbook_dsn;
-      
-      // Create a new addressbook object
-      $abook = new AddressBook;
-      
-      // Always add a local backend. We use *either* file-based *or* a
-      // database addressbook. If $addrbook_dsn is set, the database
-      // backend is used. If not, addressbooks are stores in files.
-      if(isset($addrbook_dsn) && !empty($addrbook_dsn)) {
-	 // Database
-	 $r = $abook->add_backend('database', Array('dsn' => $addrbook_dsn,
-						    'owner' => $username,
-						    'table' => 'address'));
-	 if(!$r && $showerr) {
-	    printf(_("Error initializing addressbook database."));
-	    exit;
-	 }
-      } else {
-	 // File
-	 $filename = getHashedFile($username, $data_dir, "$username.abook");
-	 $r = $abook->add_backend('local_file', Array('filename' => $filename,
-						      'create'   => true));
-	 if(!$r && $showerr) {
-	    printf(_("Error opening file %s"), $filename);
-	    exit;
-	 }
-	 
-      }
-
-      // This would be for the global addressbook
-      if (isset($address_book_global_filename)) {
-         $r = $abook->add_backend('global_file');
-         if (!$r && $showerr) {
-             printf(_("Error initializing global addressbook."));
-	     exit;
-         }
-      }
-
-      if($onlylocal)
-	return $abook;
-
-      // Load configured LDAP servers (if PHP has LDAP support)
-      if(isset($ldap_server) && is_array($ldap_server) && 
-          function_exists('ldap_connect')) {
-	 reset($ldap_server);
-	 while(list($undef,$param) = each($ldap_server)) {
-	    if(is_array($param)) {
-	       $r = $abook->add_backend('ldap_server', $param);
-	       if(!$r && $showerr) {
-		  printf(' ' . _("Error initializing LDAP server %s:") .
-		       "<BR>\n", $param['host']);
-		  print('&nbsp;' . $abook->error);
-		  exit;
-	       }
-	    }
-	 }
-      }
-
-      // Return the initialized object
-      return $abook;
-   }
-
-   
-   // Had to move this function outside of the Addressbook Class
-   // PHP 4.0.4 Seemed to be having problems with inline functions.
-   function addressbook_cmp($a,$b) {   
-      if($a['backend'] > $b['backend']) 
-	     return 1;
-	  else if($a['backend'] < $b['backend']) 
-	     return -1;
-	  return (strtolower($a['name']) > strtolower($b['name'])) ? 1 : -1;
-   }
-
-
-  /**
-   ** This is the main address book class that connect all the
-   ** backends and provide services to the functions above.
-   **
-   **/
-   
-   class AddressBook { 
-      var $backends    = array();
-      var $numbackends = 0;
-      var $error       = '';
-      var $localbackend = 0;
-      var $localbackendname = '';
+global $addrbook_dsn;
+
+/* Use this if you wanna have a global address book */
+if (isset($address_book_global_filename)) {
+    include_once('../functions/abook_global_file.php');
+}
+
+/* Only load database backend if database is configured */
+if(isset($addrbook_dsn)) {
+  include_once('../functions/abook_database.php');
+}
+
+/*
+   Create and initialize an addressbook object.
+   Returns the created object
+*/
+function addressbook_init($showerr = true, $onlylocal = false) {
+    global $data_dir, $username, $ldap_server, $address_book_global_filename;
+    global $addrbook_dsn;
+
+    /* Create a new addressbook object */
+    $abook = new AddressBook;
+
+    /*
+        Always add a local backend. We use *either* file-based *or* a
+        database addressbook. If $addrbook_dsn is set, the database
+        backend is used. If not, addressbooks are stores in files.
+    */
+    if (isset($addrbook_dsn) && !empty($addrbook_dsn)) {
+        /* Database */
+        $r = $abook->add_backend('database', Array('dsn' => $addrbook_dsn,
+                            'owner' => $username,
+                            'table' => 'address'));
+        if (!$r && $showerr) {
+            echo _("Error initializing addressbook database.");
+            exit;
+        }
+    } else {
+        /* File */
+        $filename = getHashedFile($username, $data_dir, "$username.abook");
+        $r = $abook->add_backend('local_file', Array('filename' => $filename,
+                              'create'   => true));
+        if(!$r && $showerr) {
+            printf( _("Error opening file %s"), $filename );
+            exit;
+        }
+
+    }
+
+    /* This would be for the global addressbook */
+    if (isset($address_book_global_filename)) {
+        $r = $abook->add_backend('global_file');
+        if (!$r && $showerr) {
+            echo _("Error initializing global addressbook.");
+            exit;
+        }
+    }
+
+    if ($onlylocal) {
+        return $abook;
+    }
+
+    /* Load configured LDAP servers (if PHP has LDAP support) */
+    if (isset($ldap_server) && is_array($ldap_server) && function_exists('ldap_connect')) {
+        reset($ldap_server);
+        while (list($undef,$param) = each($ldap_server)) {
+            if (is_array($param)) {
+                $r = $abook->add_backend('ldap_server', $param);
+                if (!$r && $showerr) {
+                    printf( '&nbsp;' . _("Error initializing LDAP server %s:") .
+                            "<BR>\n", $param['host']);
+                    echo '&nbsp;' . $abook->error;
+                    exit;
+                }
+            }
+        }
+    }
+
+    /* Return the initialized object */
+    return $abook;
+}
+
+
+/*
+ *   Had to move this function outside of the Addressbook Class
+ *   PHP 4.0.4 Seemed to be having problems with inline functions.
+ */    
+function addressbook_cmp($a,$b) {
+
+    if($a['backend'] > $b['backend']) {
+        return 1;
+    } else if($a['backend'] < $b['backend']) {
+        return -1;
+    }
+    
+    return (strtolower($a['name']) > strtolower($b['name'])) ? 1 : -1;
+
+}
+
+
+/*
+ * This is the main address book class that connect all the
+ * backends and provide services to the functions above.
+ *
+ */
 
+class AddressBook {
+
+    var $backends    = array();
+    var $numbackends = 0;
+    var $error       = '';
+    var $localbackend = 0;
+    var $localbackendname = '';
+    
       // Constructor function.
-      function AddressBook() {
-	 $localbackendname = _("Personal address book");
-      }
-
-      // Return an array of backends of a given type, 
-      // or all backends if no type is specified.
-      function get_backend_list($type = '') {
-	 $ret = array();
-	 for($i = 1 ; $i <= $this->numbackends ; $i++) {
-	    if(empty($type) || $type == $this->backends[$i]->btype) {
-	       $ret[] = &$this->backends[$i];
-	    }
-	 }
-	 return $ret;
-      }
-
-
-      // ========================== Public ========================
-
-      // Add a new backend. $backend is the name of a backend
-      // (without the abook_ prefix), and $param is an optional
-      // mixed variable that is passed to the backend constructor.
-      // See each of the backend classes for valid parameters.
-      function add_backend($backend, $param = '') {
-	 $backend_name = 'abook_' . $backend;
-	 eval('$newback = new ' . $backend_name . '($param);');
-	 if(!empty($newback->error)) {
-	    $this->error = $newback->error;
-	    return false;
-	 }
-
-	 $this->numbackends++;
-       
-	 $newback->bnum = $this->numbackends;
-	 $this->backends[$this->numbackends] = $newback;
-
-	 // Store ID of first local backend added
-	 if($this->localbackend == 0 && $newback->btype == 'local') {
-	    $this->localbackend = $this->numbackends;
-	    $this->localbackendname = $newback->sname;
-	 }
-
-	 return $this->numbackends;
-      }
-
-
-      // Return a list of addresses matching expression in
-      // all backends of a given type.
-      function search($expression, $bnum = -1) {
-	 $ret = array();
-	 $this->error = '';
-
-	 // Search all backends
-	 if($bnum == -1) {
-	    $sel = $this->get_backend_list('');
-	    $failed = 0;
-	    for($i = 0 ; $i < sizeof($sel) ; $i++) {
-	       $backend = &$sel[$i];
-	       $backend->error = '';
-	       $res = $backend->search($expression);
-	       if(is_array($res)) {
-		  $ret = array_merge($ret, $res);
-	       } else {
-		  $this->error .= "<br>\n" . $backend->error;
-		  $failed++;
-	       }
-	    }
-
-	    // Only fail if all backends failed
-	    if($failed >= sizeof($sel))
-	       return false;
-
-	 }
-
-	 // Search only one backend
-	 else {
-	    $ret = $this->backends[$bnum]->search($expression);
-	    if(!is_array($ret)) {
-	       $this->error .= "<br>\n" . $this->backends[$bnum]->error;
-	       return false;
-	    }
-	 }
-
-	 return $ret;
-      }
-
-      
-      // Return a sorted search
-      function s_search($expression, $bnum = -1) {
-	      
-    	 $ret = $this->search($expression, $bnum);
-    	 if(!is_array($ret))
-    	    return $ret;
-	     usort($ret, 'addressbook_cmp');
-	     return $ret;
-      }
-
-
-      // Lookup an address by alias. Only possible in
-      // local backends.
-      function lookup($alias, $bnum = -1) {
-	 $ret = array();
-
-	 if($bnum > -1) {
-	    $res = $this->backends[$bnum]->lookup($alias);
-	    if(is_array($res)) {
-	       return $res;
-	    } else {
-	       $this->error = $backend->error;
-	       return false;
-	    }
-	 }     
-
-	 $sel = $this->get_backend_list('local');
-	 for($i = 0 ; $i < sizeof($sel) ; $i++) {
-	    $backend = &$sel[$i];
-	    $backend->error = '';
-	    $res = $backend->lookup($alias);
-	    if(is_array($res)) {
-	       if(!empty($res))
-		  return $res;
-	    } else {
-	       $this->error = $backend->error;
-	       return false;
-	    }
-	 }
-
-	 return $ret;
-      }
-
-
-      // Return all addresses
-      function list_addr($bnum = -1) {
-	 $ret = array();
-
-	 if($bnum == -1) 
-	    $sel = $this->get_backend_list('local');
-	 else
-	    $sel = array(0 => &$this->backends[$bnum]);
-
-	 for($i = 0 ; $i < sizeof($sel) ; $i++) {
-	    $backend = &$sel[$i];
-	    $backend->error = '';
-	    $res = $backend->list_addr();
-	    if(is_array($res)) {
-	       $ret = array_merge($ret, $res);
-	    } else {
-	       $this->error = $backend->error;
-	       return false;
-	    }
-	 }
-
-	 return $ret;
-      }
-
-
-      // Create a new address from $userdata, in backend $bnum.
-      // Return the backend number that the/ address was added
-      // to, or false if it failed.
-      function add($userdata, $bnum) {
-
-	 // Validate data
-	 if(!is_array($userdata)) {
-	    $this->error = _("Invalid input data");
-	    return false;
-	 }
-	 if(empty($userdata['firstname']) &&
-	    empty($userdata['lastname'])) {
-	    $this->error = _("Name is missing");
-	    return false;
-	 }
-	 if(empty($userdata['email'])) {
-	    $this->error = _("E-mail address is missing");
-	    return false;
-	 }
-	 if(empty($userdata['nickname'])) {
-	    $userdata['nickname'] = $userdata['email'];
-	 }
-
-	 if(eregi('[ \\:\\|\\#\\"\\!]', $userdata['nickname'])) {
-	    $this->error = _("Nickname contains illegal characters");
-	    return false;
-	 }
-
-	 // Check that specified backend accept new entries
-	 if(!$this->backends[$bnum]->writeable) {
-	    $this->error = _("Addressbook is read-only");
-	    return false;
-	 }
-
-	 // Add address to backend
-	 $res = $this->backends[$bnum]->add($userdata);
-	 if($res) {
-	    return $bnum;
-	 } else {
-	    $this->error = $this->backends[$bnum]->error;
-	    return false;
-	 }
-
-	 return false;  // Not reached
-      } // end of add()
-
-
-      // Remove the user identified by $alias from backend $bnum
-      // If $alias is an array, all users in the array are removed.
-      function remove($alias, $bnum) {
-
-	 // Check input
-	 if(empty($alias))
-	    return true;
-
-	 // Convert string to single element array
-	 if(!is_array($alias))
-	   $alias = array(0 => $alias);
-
-	 // Check that specified backend is writable
-	 if(!$this->backends[$bnum]->writeable) {
-	    $this->error = _("Addressbook is read-only");
-	    return false;
-	 }
-
-	 // Remove user from backend
-	 $res = $this->backends[$bnum]->remove($alias);
-	 if($res) {
-	    return $bnum;
-	 } else {
-	    $this->error = $this->backends[$bnum]->error;
-	    return false;
-	 }
-
-	 return false;  // Not reached
-      } // end of remove()
-
-
-      // Remove the user identified by $alias from backend $bnum
-      // If $alias is an array, all users in the array are removed.
-      function modify($alias, $userdata, $bnum) {
-
-	 // Check input
-	 if(empty($alias) || !is_string($alias))
-	    return true;
-
-	 // Validate data
-	 if(!is_array($userdata)) {
-	    $this->error = _("Invalid input data");
-	    return false;
-	 }
-	 if(empty($userdata['firstname']) &&
-	    empty($userdata['lastname'])) {
-	    $this->error = _("Name is missing");
-	    return false;
-	 }
-	 if(empty($userdata['email'])) {
-	    $this->error = _("E-mail address is missing");
-	    return false;
-	 }
-
-	 if(eregi('[\\: \\|\\#"\\!]', $userdata['nickname'])) {
-	    $this->error = _("Nickname contains illegal characters");
-	    return false;
-	 }
-
-	 if(empty($userdata['nickname'])) {
-	    $userdata['nickname'] = $userdata['email'];
-	 }
-
-	 // Check that specified backend is writable
-	 if(!$this->backends[$bnum]->writeable) {
-	    $this->error = _("Addressbook is read-only");;
-	    return false;
-	 }
-
-	 // Modify user in backend
-	 $res = $this->backends[$bnum]->modify($alias, $userdata);
-	 if($res) {
-	    return $bnum;
-	 } else {
-	    $this->error = $this->backends[$bnum]->error;
-	    return false;
-	 }
-
-	 return false;  // Not reached
-      } // end of modify()
-
-
-   } // End of class Addressbook
-
-  /**
-   ** Generic backend that all other backends extend
-   **/
-   class addressbook_backend {
-
-      // Variables that all backends must provide.
-      var $btype      = 'dummy';
-      var $bname      = 'dummy';
-      var $sname      = 'Dummy backend';
-
-      // Variables common for all backends, but that 
-      // should not be changed by the backends.
-      var $bnum       = -1;
-      var $error      = '';
-      var $writeable  = false;
-
-      function set_error($string) {
-	 $this->error = '[' . $this->sname . '] ' . $string;
-	 return false;
-      }
-
-
-      // ========================== Public ========================
-
-      function search($expression) {
-	 $this->set_error('search not implemented');
-	 return false;
-      }
-
-      function lookup($alias) {
-	 $this->set_error('lookup not implemented');
-	 return false;
-      }
-
-      function list_addr() {
-	 $this->set_error('list_addr not implemented');
-	 return false;
-      }
-
-      function add($userdata) {
-	 $this->set_error('add not implemented');
-	 return false;
-      }
-
-      function remove($alias) {
-	 $this->set_error('delete not implemented');
-	 return false;
-      }
-
-      function modify($alias, $newuserdata) {
-	 $this->set_error('modify not implemented');
-	 return false;
-      }
-
-   }
-
-?>
+    function AddressBook() {
+        $localbackendname = _("Personal address book");
+    }
+
+    /*
+     * Return an array of backends of a given type,
+     * or all backends if no type is specified.
+     */
+    function get_backend_list($type = '') {
+        $ret = array();
+        for ($i = 1 ; $i <= $this->numbackends ; $i++) {
+            if (empty($type) || $type == $this->backends[$i]->btype) {
+                $ret[] = &$this->backends[$i];
+            }
+        }
+        return $ret;
+    }
+
+
+    /*
+       ========================== Public ========================
+
+        Add a new backend. $backend is the name of a backend
+        (without the abook_ prefix), and $param is an optional
+        mixed variable that is passed to the backend constructor.
+        See each of the backend classes for valid parameters.
+     */
+    function add_backend($backend, $param = '') {
+        $backend_name = 'abook_' . $backend;
+        eval('$newback = new ' . $backend_name . '($param);');
+        if(!empty($newback->error)) {
+            $this->error = $newback->error;
+            return false;
+        }
+
+        $this->numbackends++;
+
+        $newback->bnum = $this->numbackends;
+        $this->backends[$this->numbackends] = $newback;
+        
+        /* Store ID of first local backend added */
+        if ($this->localbackend == 0 && $newback->btype == 'local') {
+            $this->localbackend = $this->numbackends;
+            $this->localbackendname = $newback->sname;
+        }
+
+        return $this->numbackends;
+    }
+
+
+    /*
+        Return a list of addresses matching expression in
+        all backends of a given type.
+    */
+    function search($expression, $bnum = -1) {
+        $ret = array();
+        $this->error = '';
+
+        /* Search all backends */
+        if ($bnum == -1) {
+            $sel = $this->get_backend_list('');
+            $failed = 0;
+            for ($i = 0 ; $i < sizeof($sel) ; $i++) {
+                $backend = &$sel[$i];
+                $backend->error = '';
+                $res = $backend->search($expression);
+                if (is_array($res)) {
+                    $ret = array_merge($ret, $res);
+                } else {
+                    $this->error .= "<br>\n" . $backend->error;
+                    $failed++;
+                }
+            }
+
+            /* Only fail if all backends failed */
+            if( $failed >= sizeof( $sel ) ) {
+                $ret = FALSE;
+            }
+
+        }  else {
+
+            /* Search only one backend */
+
+            $ret = $this->backends[$bnum]->search($expression);
+            if (!is_array($ret)) {
+                $this->error .= "<br>\n" . $this->backends[$bnum]->error;
+                $ret = FALSE;
+            }
+        }
+
+        return( $ret );
+    }
+
+
+    /* Return a sorted search */
+    function s_search($expression, $bnum = -1) {
+    
+        $ret = $this->search($expression, $bnum);
+        if ( is_array( $ret ) ) {
+            usort($ret, 'addressbook_cmp');
+        }    
+        return $ret;
+    }
+
+
+    /*
+     *  Lookup an address by alias. Only possible in
+     *  local backends.
+     */
+    function lookup($alias, $bnum = -1) {
+    
+        $ret = array();
+    
+        if ($bnum > -1) {
+            $res = $this->backends[$bnum]->lookup($alias);
+            if (is_array($res)) {
+               return $res;
+            } else {
+               $this->error = $backend->error;
+               return false;
+            }
+        }
+    
+        $sel = $this->get_backend_list('local');
+        for ($i = 0 ; $i < sizeof($sel) ; $i++) {
+            $backend = &$sel[$i];
+            $backend->error = '';
+            $res = $backend->lookup($alias);
+            if (is_array($res)) {
+               if(!empty($res))
+              return $res;
+            } else {
+               $this->error = $backend->error;
+               return false;
+            }
+        }
+        
+        return $ret;
+    }
+
+
+    /* Return all addresses */
+    function list_addr($bnum = -1) {
+        $ret = array();
+        
+        if ($bnum == -1) {
+            $sel = $this->get_backend_list('local');
+        } else {
+            $sel = array(0 => &$this->backends[$bnum]);
+        }
+        
+        for ($i = 0 ; $i < sizeof($sel) ; $i++) {
+            $backend = &$sel[$i];
+            $backend->error = '';
+            $res = $backend->list_addr();
+            if (is_array($res)) {
+               $ret = array_merge($ret, $res);
+            } else {
+               $this->error = $backend->error;
+               return false;
+            }
+        }
+        
+        return $ret;
+    }
+
+
+    /*
+     * Create a new address from $userdata, in backend $bnum.
+     * Return the backend number that the/ address was added
+     * to, or false if it failed.
+     */
+    function add($userdata, $bnum) {
+    
+        /* Validate data */
+        if (!is_array($userdata)) {
+            $this->error = _("Invalid input data");
+            return false;
+        }
+        if (empty($userdata['firstname']) && empty($userdata['lastname'])) {
+            $this->error = _("Name is missing");
+            return false;
+        }
+        if (empty($userdata['email'])) {
+            $this->error = _("E-mail address is missing");
+            return false;
+        }
+        if (empty($userdata['nickname'])) {
+            $userdata['nickname'] = $userdata['email'];
+        }
+        
+        if (eregi('[ \\:\\|\\#\\"\\!]', $userdata['nickname'])) {
+            $this->error = _("Nickname contains illegal characters");
+            return false;
+        }
+        
+        /* Check that specified backend accept new entries */
+        if (!$this->backends[$bnum]->writeable) {
+            $this->error = _("Addressbook is read-only");
+            return false;
+        }
+        
+        /* Add address to backend */
+        $res = $this->backends[$bnum]->add($userdata);
+        if ($res) {
+            return $bnum;
+        } else {
+            $this->error = $this->backends[$bnum]->error;
+            return false;
+        }
+        
+        return false;  // Not reached
+    } /* end of add() */
+
+
+    /*
+     * Remove the user identified by $alias from backend $bnum
+     * If $alias is an array, all users in the array are removed.
+     */
+    function remove($alias, $bnum) {
+    
+        /* Check input */
+        if (empty($alias)) {
+            return true;
+        }
+        
+        /* Convert string to single element array */
+        if (!is_array($alias)) {
+            $alias = array(0 => $alias);
+        }
+        
+        /* Check that specified backend is writable */
+        if (!$this->backends[$bnum]->writeable) {
+            $this->error = _("Addressbook is read-only");
+            return false;
+        }
+        
+        /* Remove user from backend */
+        $res = $this->backends[$bnum]->remove($alias);
+        if ($res) {
+            return $bnum;
+        } else {
+            $this->error = $this->backends[$bnum]->error;
+            return false;
+        }
+        
+        return FALSE;  /* Not reached */
+    } /* end of remove() */
+
+
+    /*
+     * Remove the user identified by $alias from backend $bnum
+     * If $alias is an array, all users in the array are removed.
+     */
+    function modify($alias, $userdata, $bnum) {
+    
+        /* Check input */
+        if (empty($alias) || !is_string($alias)) {
+            return true;
+        }
+        
+        /* Validate data */
+        if(!is_array($userdata)) {
+            $this->error = _("Invalid input data");
+            return false;
+        }
+        if (empty($userdata['firstname']) && empty($userdata['lastname'])) {
+            $this->error = _("Name is missing");
+            return false;
+        }
+        if (empty($userdata['email'])) {
+            $this->error = _("E-mail address is missing");
+            return false;
+        }
+        
+        if (eregi('[\\: \\|\\#"\\!]', $userdata['nickname'])) {
+            $this->error = _("Nickname contains illegal characters");
+            return false;
+        }
+        
+        if (empty($userdata['nickname'])) {
+            $userdata['nickname'] = $userdata['email'];
+        }
+        
+        /* Check that specified backend is writable */
+        if (!$this->backends[$bnum]->writeable) {
+            $this->error = _("Addressbook is read-only");;
+            return false;
+        }
+        
+        /* Modify user in backend */
+        $res = $this->backends[$bnum]->modify($alias, $userdata);
+        if ($res) {
+            return $bnum;
+        } else {
+            $this->error = $this->backends[$bnum]->error;
+            return false;
+        }
+        
+        return FALSE;  /* Not reached */
+    } /* end of modify() */
+    
+    
+} /* End of class Addressbook */
+
+/*
+ * Generic backend that all other backends extend
+ */
+class addressbook_backend {
+
+    /* Variables that all backends must provide. */
+    var $btype      = 'dummy';
+    var $bname      = 'dummy';
+    var $sname      = 'Dummy backend';
+    
+    /*
+     * Variables common for all backends, but that
+     * should not be changed by the backends.
+     */
+    var $bnum       = -1;
+    var $error      = '';
+    var $writeable  = false;
+    
+    function set_error($string) {
+        $this->error = '[' . $this->sname . '] ' . $string;
+        return false;
+    }
+    
+    
+    /* ========================== Public ======================== */
+    
+    function search($expression) {
+        $this->set_error('search not implemented');
+        return false;
+    }
+    
+    function lookup($alias) {
+        $this->set_error('lookup not implemented');
+        return false;
+    }
+    
+    function list_addr() {
+        $this->set_error('list_addr not implemented');
+        return false;
+    }
+    
+    function add($userdata) {
+        $this->set_error('add not implemented');
+        return false;
+    }
+    
+    function remove($alias) {
+        $this->set_error('delete not implemented');
+        return false;
+    }
+    
+    function modify($alias, $newuserdata) {
+        $this->set_error('modify not implemented');
+        return false;
+    }
+
+}
+
+?>