webserver: handle "If-Modified-Since" header for better caching

Montellese · Sep 6, 2012 · e3c5071 · e3c5071
1 parent e9ab7ad
commit e3c5071
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Showing 2 changed files with 42 additions and 7 deletions.
diff --git a/xbmc/network/WebServer.cpp b/xbmc/network/WebServer.cpp
@@ -275,6 +275,7 @@ int CWebServer::HandleRequest(IHTTPRequestHandler *handler, const HTTPRequest &r
   }
 
   struct MHD_Response *response = NULL;
+  int responseCode = handler->GetHTTPResonseCode();
   switch (handler->GetHTTPResponseType())
   {
     case HTTPNone:
@@ -286,7 +287,7 @@ int CWebServer::HandleRequest(IHTTPRequestHandler *handler, const HTTPRequest &r
       break;
 
     case HTTPFileDownload:
-      ret = CreateFileDownloadResponse(request.connection, handler->GetHTTPResponseFile(), request.method, response);
+      ret = CreateFileDownloadResponse(request.connection, handler->GetHTTPResponseFile(), request.method, response, responseCode);
       break;
 
     case HTTPMemoryDownloadNoFreeNoCopy:
@@ -324,7 +325,7 @@ int CWebServer::HandleRequest(IHTTPRequestHandler *handler, const HTTPRequest &r
   for (multimap<string, string>::const_iterator it = header.begin(); it != header.end(); it++)
     MHD_add_response_header(response, it->first.c_str(), it->second.c_str());
 
-  MHD_queue_response(request.connection, handler->GetHTTPResonseCode(), response);
+  MHD_queue_response(request.connection, responseCode, response);
   MHD_destroy_response(response);
   delete handler;
 
@@ -354,15 +355,43 @@ int CWebServer::CreateRedirect(struct MHD_Connection *connection, const string &
   return MHD_NO;
 }
 
-int CWebServer::CreateFileDownloadResponse(struct MHD_Connection *connection, const string &strURL, HTTPMethod methodType, struct MHD_Response *&response)
+int CWebServer::CreateFileDownloadResponse(struct MHD_Connection *connection, const string &strURL, HTTPMethod methodType, struct MHD_Response *&response, int &responseCode)
 {
   CFile *file = new CFile();
 
   if (file->Open(strURL, READ_NO_CACHE))
   {
+    bool getData = true;
     if (methodType != HEAD)
     {
-      response = MHD_create_response_from_callback ( file->GetLength(),
+      if (methodType == GET)
+      {
+        string ifModifiedSince = GetRequestHeaderValue(connection, MHD_HEADER_KIND, "If-Modified-Since");
+        if (!ifModifiedSince.empty())
+        {
+          CDateTime ifModifiedSinceDate;
+          ifModifiedSinceDate.SetFromRFC1123DateTime(ifModifiedSince);
+
+          struct __stat64 statBuffer;
+          if (file->Stat(&statBuffer) == 0)
+          {
+            struct tm *time = localtime((time_t *)&statBuffer.st_mtime);
+            if (time != NULL)
+            {
+              CDateTime lastModified = *time;
+              if (lastModified.GetAsUTCDateTime() <= ifModifiedSinceDate)
+              {
+                getData = false;
+                response = MHD_create_response_from_data (0, NULL, MHD_NO, MHD_NO);
+                responseCode = MHD_HTTP_NOT_MODIFIED;
+              }
+            }
+          }
+        }
+      }
+
+      if (getData)
+        response = MHD_create_response_from_callback(file->GetLength(),
                                                      2048,
                                                      &CWebServer::ContentReaderCallback, file,
                                                      &CWebServer::ContentReaderFreeCallback);
@@ -371,6 +400,8 @@ int CWebServer::CreateFileDownloadResponse(struct MHD_Connection *connection, co
     }
     else
     {
+      getData = false;
+
       CStdString contentLength;
       contentLength.Format("%I64d", file->GetLength());
 
@@ -408,8 +439,12 @@ int CWebServer::CreateFileDownloadResponse(struct MHD_Connection *connection, co
     expiryTime += CDateTimeSpan(365, 0, 0, 0);
     MHD_add_response_header(response, "Expires", expiryTime.GetAsRFC1123DateTime());
 
-    file->Close();
-    delete file;
+    // only close the CFile instance if libmicrohttpd doesn't have to grab the data of the file
+    if (!getData)
+    {
+      file->Close();
+      delete file;
+    }
   }
   else
   {

diff --git a/xbmc/network/WebServer.h b/xbmc/network/WebServer.h
@@ -92,7 +92,7 @@ class CWebServer : public JSONRPC::ITransportLayer
   static int HandleRequest(IHTTPRequestHandler *handler, const HTTPRequest &request);
   static void ContentReaderFreeCallback (void *cls);
   static int CreateRedirect(struct MHD_Connection *connection, const std::string &strURL, struct MHD_Response *&response);
-  static int CreateFileDownloadResponse(struct MHD_Connection *connection, const std::string &strURL, HTTPMethod methodType, struct MHD_Response *&response);
+  static int CreateFileDownloadResponse(struct MHD_Connection *connection, const std::string &strURL, HTTPMethod methodType, struct MHD_Response *&response, int &responseCode);
   static int CreateErrorResponse(struct MHD_Connection *connection, int responseType, HTTPMethod method, struct MHD_Response *&response);
   static int CreateMemoryDownloadResponse(struct MHD_Connection *connection, void *data, size_t size, bool free, bool copy, struct MHD_Response *&response);