Dear All, I have recently written a small Web Server application using the THttpServer component in ICS 5 with C++ Builder 5.
It serves GET requests perfectly, but when I added POST functionality, (following the WebServ example) it has started generating EAccessViolations. CodeGuard reports that these are due to my PostedDataBuffer having only a 1 byte heap length when I am writing the NULL string termination character in the "HttpServerPostedData" event handler. I have managed to improve the code reliability by not dynamically allocating the PostedDataBuffer at all, (but this is not an acceptable solution). In the code snippets below I pre-allocate once in the constructor but this still generates AV's. Can anyone shed some light on what might be happening here? Regards, Keith Willis. <<< CODE SNIPPETS >>> //-------------------------------------------------------------------------- - class TMyHttpConnection : public THttpConnection { public: char* Junk; char *PostedDataBuffer; // Will hold dynamically allocated buffer int PostedDataSize; // Databuffer size int RcvdByteCount; // Keep track of received byte count. public: __fastcall TMyHttpConnection(Classes::TComponent* AOwner); virtual __fastcall ~TMyHttpConnection(); }; //-------------------------------------------------------------------------- - //-------------------------------------------------------------------------- - __fastcall TMyHttpConnection::TMyHttpConnection(Classes::TComponent* AOwner) : THttpConnection(AOwner) { try { Junk = new char(65536); PostedDataBuffer = new char(65536); // Pre-allocate here in a desperate attempt to avoid EAccessViolations PostedDataSize = 65536; } catch(...) {} } //-------------------------------------------------------------------------- - __fastcall TMyHttpConnection::~TMyHttpConnection() { try { delete [] Junk; delete [] PostedDataBuffer; PostedDataBuffer = NULL; PostedDataSize = 0; } catch(...) {} } //-------------------------------------------------------------------------- - //-------------------------------------------------------------------------- - void __fastcall TAegisWebServerForm::HttpServerPostedData(TObject *Sender, TObject *Client, WORD Error) { try { int Len, Remains; TMyHttpConnection* Connection = (TMyHttpConnection*)Client; Remains = Connection->RequestContentLength - Connection->RcvdByteCount; if (Remains <= 0) { Len = Connection->Receive(Connection->Junk, sizeof(Connection->Junk)- 1); if (Len >= 0) Connection->Junk[Len] = 0; return; } // Len = Connection->Receive(Connection->PostedDataBuffer + Connection->RcvdByteCount, Remains); Len = Connection->Receive(&(Connection->PostedDataBuffer[Connection->RcvdByteCount ]), Remains); if (Len <= 0) return; Connection->RcvdByteCount += Len; if (Connection->RcvdByteCount > Connection->RequestContentLength) Connection->RcvdByteCount = Connection->RequestContentLength; if (Connection->RcvdByteCount == Connection->RequestContentLength) { Connection->PostedDataBuffer[Connection->RcvdByteCount] = 0; // <= CRASHES HERE! CodeGuard reports that the Heap length of is only 1 byte at this point??? if (CompareText(Connection->Path, "/content/home.html") == 0) ProcessPostedData(Connection); // else Connection->Answer404(); // I need to make Answer404 accessible else { AnsiString Body = AnsiString("<HTML><HEAD><TITLE>404 Not Found</TITLE></HEAD><BODY><H1>404 Not Found</H1>The requested URL ") + TextToHtmlText(Connection->Path) + " was not found on this server.<P></BODY></HTML>\r\n"; Connection->SendHeader(Connection->Version + " 404 Not Found\r\nContent-Type: text/html\r\nContent-Length: " + Utility->IntToStrEx(Body.Length()) + "\r\n\r\n"); Connection->SendStr(Body); } Connection->PostedDataReceived(); } } catch (Exception &E) {HandleError("TAegisWebServerForm::HttpServerPostedData", E.Message);} catch (const exception &e) {HandleError("TAegisWebServerForm::HttpServerPostedData", e.what());} catch (...) {HandleError("TAegisWebServerForm::HttpServerPostedData", "Unknown Exception");} } //-------------------------------------------------------------------------- - -- To unsubscribe or change your settings for TWSocket mailing list please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be