--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Plugin/CachedAuthorizationService.cpp	Wed Mar 22 16:13:52 2017 +0100
@@ -0,0 +1,99 @@
+/**
+ * Advanced authorization plugin for Orthanc
+ * Copyright (C) 2017 Osimis, Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#include "CachedAuthorizationService.h"
+
+#include "../Resources/Orthanc/Core/OrthancException.h"
+
+#include <boost/lexical_cast.hpp>
+
+namespace OrthancPlugins
+{
+  std::string CachedAuthorizationService::ComputeKey(OrthancPluginHttpMethod method,
+                                                     const AccessedResource& access,
+                                                     const Token& token,
+                                                     const std::string& tokenValue) const
+  {
+    return (boost::lexical_cast<std::string>(method) + "|" +
+            boost::lexical_cast<std::string>(access.GetLevel()) + "|" +
+            access.GetOrthancId() + "|" + token.GetKey() + "|" + tokenValue);
+  }
+    
+
+  CachedAuthorizationService::CachedAuthorizationService(IAuthorizationService* decorated /* takes ownership */,
+                                                         ICacheFactory& factory) :
+    decorated_(decorated),
+    cache_(factory.Create())
+  {
+    if (decorated_.get() == NULL)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+    }
+  }
+
+
+  bool CachedAuthorizationService::IsGranted(unsigned int& validity,
+                                             OrthancPluginHttpMethod method,
+                                             const AccessedResource& access,
+                                             const Token& token,
+                                             const std::string& tokenValue)
+  {
+    assert(decorated_.get() != NULL);
+
+    std::string key = ComputeKey(method, access, token, tokenValue);
+    std::string value;
+
+    if (cache_->Retrieve(value, key))
+    {
+      // Return the previously cached value
+      return (value == "1");
+    }        
+        
+    bool granted = decorated_->IsGranted(validity, method, access, token, tokenValue);
+
+    if (granted)
+    {
+      if (validity > 0)
+      {
+        cache_->Store(key, "1", validity);
+      }
+        
+      return true;
+    }
+    else
+    {
+      if (validity > 0)
+      {
+        cache_->Store(key, "0", validity);
+      }
+        
+      return false;
+    }
+  }
+
+  
+  bool CachedAuthorizationService::IsGranted(unsigned int& validity,
+                                             OrthancPluginHttpMethod method,
+                                             const AccessedResource& access)
+  {
+    assert(decorated_.get() != NULL);
+
+    // The cache is not used if no token is available
+    return decorated_->IsGranted(validity, method, access);
+  }
+}