Concurrent access to guests.xml file

Benjamin Renard
1 parent 22609c36
Showing 1 changed file with 129 additions and 90 deletions Show diff stats
php/classes/Guest.php
@@ -7,117 +7,156 @@
  
 class Guest {
  
-    private $guestXml, $guestXmlFile, $xp, $root;
+    private $guestXmlFile;
     public  $Id, $Start, $Ip, $email;
  
     function __construct($Ip_, $email_ = null){
-      
         if($email_) {
-           $this->Start = getdate();
-           $this->Ip = $Ip_;
-           $this->email = $email_;  
-          }
-         else {
-             $this->Id = substr($Ip_,strlen("guest"));
-          }
-
-         $this->guestXmlFile = DATAPATH."guests.xml";
-         $this->guestXml  =  new DomDocument("1.0");
-
-         if (!file_exists($this->guestXmlFile)){
-            $status = $this->generateXML();
-         }
-         else {
-            $this->guestXml->load($this->guestXmlFile);
-            $this->root = $this->guestXml->getElementsByTagName("guests")->item(0);
+            $this->Start = getdate();
+            $this->Ip = $Ip_;
+            $this->email = $email_;  
         }
-        $this->xp = new domxpath($this->guestXml);  
+        else {
+            $this->Id = substr($Ip_,strlen("guest"));
+        }
+
+        $this->guestXmlFile = DATAPATH."guests.xml";
+    }
+
+    public function checkGuestTimes() {
+        return $this->concurrentAccessGuestFile(array($this,'_checkGuestTimes'));
+    }
+
+    public function deleteGuest() {
+        return $this->concurrentAccessGuestFile(array($this,'_deleteGuest'));
+    }
+
+    public function addGuest(){
+        return $this->concurrentAccessGuestFile(array($this,'_addGuest'));
     }
  
-    private function generateXML() {
-        $this->root = $this->guestXml->createElement('guests'); 
-        $this->guestXml->appendChild($this->root);
+    public function registerGuest(){
+        return $this->concurrentAccessGuestFile(array($this,'_registerGuest'));
+    }
+
+    private function concurrentAccessGuestFile($callback) {
+        $lockFile =  $this->guestXmlFile.".lockfile";
+
+        $fp = fopen($lockFile, "w+");
+
+        if ($fp === false) {
+            return false;
+        }
  
-        $status = $this->guestXml->save($this->guestXmlFile);
+        $res = true;
  
-        return $status;
+        if (flock($fp, LOCK_EX))
+        {
+            if (!file_exists($this->guestXmlFile)) {
+                $res = $this->_generateXML();
+            }
+
+            if ($res) {
+                $dom = new DomDocument("1.0","UTF-8");
+                $dom->preserveWhiteSpace = false;
+                $dom->formatOutput = true;
+                $res = $dom->load($this->guestXmlFile);
+                if ($res) {
+                    $func_res = call_user_func($callback,$dom);
+                }
+            }
+        }
+        else
+            $res = false;
+
+        fclose($fp);
+
+        if ($res)
+            return $func_res;
+
+        return false;
+    }
+
+    private function _generateXML() {
+        $dom = new DOMDocument("1.0","UTF-8");
+        $dom->preserveWhiteSpace = false;
+        $dom->formatOutput = true;
+        $rootNode = $dom->createElement('guests'); 
+        $dom->appendChild($rootNode);
+        return $dom->save($this->guestXmlFile);
     } 
  
-    public function GetId(){
-           
-         $elements = $this->xp->query("//@xml:id"); 
+    private function _getId($dom){
+        $xp = new DOMXpath($dom); 
+        $elements = $xp->query("//@xml:id"); 
 // Now find New Valid ID        
-            if ($elements->length > 0) {
-                     $idList = array();
-                     for ($i = 0; $i < $elements->length; $i++) 
-                           $idList[$i] = $elements->item($i)->nodeValue; 
+        if ($elements->length > 0) {
+            $idList = array();
+            for ($i = 0; $i < $elements->length; $i++) 
+                $idList[$i] = $elements->item($i)->nodeValue; 
  
-                     sort($idList);
-                     for ($i = 0; $i < $elements->length; $i++) {
-                        if ($idList[$i] > $i) { 
-                                 $newID = $i;
-                                 break;
-                           }  
-                         $newID = $i+1;  
-                      }                 
-             } else { $newID = 0;}
-
-       return $newID;
-   }
-
-   public function checkGuestTimes(){
-   
-         $Start_0 = time() - GuestSessionDuration*60; // in secs
-         $startTimes = $this->xp->query("//guest[@start<".$Start_0."]/@xml:id"); 
-
-         if ($startTimes->length > 0) {             
+            sort($idList);
+            for ($i = 0; $i < $elements->length; $i++) {
+                if ($idList[$i] > $i) { 
+                    $newID = $i;
+                    break;
+                }  
+                $newID = $i+1;  
+            }                 
+        } else { $newID = 0;}
+
+        return $newID;
+    }
+
+    private function _checkGuestTimes($dom){
+        $xp = new DOMXpath($dom);
+        $Start_0 = time() - GuestSessionDuration*60; // in secs
+        $startTimes = $xp->query("//guest[@start<".$Start_0."]/@xml:id"); 
+
+        if ($startTimes->length > 0) {
             for ($i = 0; $i < $startTimes->length; $i++) {                
-                    $user = "guest".$startTimes->item($i)->value;
-                    $this->deltree(USERPATH.$user);
-                    $this->root->removeChild($startTimes->item($i)->parentNode);  
+                $user = "guest".$startTimes->item($i)->value;
+                $this->_deltree(USERPATH.$user);
+                $dom->documentElement->removeChild($startTimes->item($i)->parentNode);
             }
-            $this->xp = new domxpath($this->guestXml);    
-         }
  
+            return $dom->save($this->guestXmlFile);
+        }
+        return true;
     }
  
-   public function deleteGuest(){
-
-            $user = "guest".$this->Id;
-            $this->deltree(USERPATH.$user);
-            $theGuest = $this->guestXml->getElementById($this->Id);
-            $this->root->removeChild($theGuest);
-            $this->guestXml->save($this->guestXmlFile);
-
- }
+    private function _deleteGuest($dom){
+        $user = "guest".$this->Id;
+        $this->_deltree(USERPATH.$user);
+        $theGuest = $dom->getElementById($this->Id);
+        $dom->documentElement->removeChild($theGuest);
+        return $dom->save($this->guestXmlFile);
+    }
  
-    public function addGuest(){
- 
-      if (($this->Id = $this->GetId()) < MaxGuests) {
-          $guest = $this->guestXml->createElement("guest");        
-          $guest->setAttribute('xml:id',$this->Id );         
-          $guest->setAttribute('start',time());
-          $guest->appendChild($this->guestXml->createElement("IP", $this->Ip));
-          $guest->appendChild($this->guestXml->createElement("email", $this->email));
-          $this->root->appendChild($guest);
-          $this->guestXml->save($this->guestXmlFile);
-
-          return "guest".$this->Id;
-      }
-       else  {  
-           return "allGuestLoginsInUse";
-      }
- }
-
-     public function registerGuest(){
-
-          $guest_file = fopen(DATAPATH.'guest.login','a'); 
-          fwrite($guest_file, $this->email." ".$this->Ip." ".$this->Start['mday']."/".$this->Start['mon']."/".$this->Start['year']."\n"); 
-          fclose($guest_file);     
+    private function _addGuest($dom){ 
+        if (($this->Id = $this->_getId($dom)) < MaxGuests) {
+            $guest = $dom->createElement("guest");        
+            $guest->setAttribute('xml:id',$this->Id );         
+            $guest->setAttribute('start',time());
+            $guest->appendChild($dom->createElement("IP", $this->Ip));
+            $guest->appendChild($dom->createElement("email", $this->email));
+            $dom->documentElement->appendChild($guest);
+            $dom->save($this->guestXmlFile);
+            return "guest".$this->Id;
+        }
+        else  {  
+            return "allGuestLoginsInUse";
+        }
+    }
  
+    private function _registerGuest($dom){
+        $guest_file = fopen(DATAPATH.'guest.login','a'); 
+        fwrite($guest_file, $this->email." ".$this->Ip." ".$this->Start['mday']."/".$this->Start['mon']."/".$this->Start['year']."\n"); 
+        fclose($guest_file);
+        return true; 
     }
  
-    public function deltree($f) {
+    private function _deltree($f) {
  
         if (is_dir($f)) {
  
@@ -125,7 +164,7 @@ class Guest {
  
             foreach($files as $sf) {
                 if (is_dir("$f/$sf") && !is_link("$f/$sf")) {
-                    $this->deltree("$f/$sf");
+                    $this->_deltree("$f/$sf");
                 } else {
                     unlink("$f/$sf");
                 }