views:

1518

answers:

3

I know how to download an html/txt page. For example :

//Variables 
DWORD dwSize = 0;
DWORD dwDownloaded = 0;
LPSTR pszOutBuffer;
vector <string>  vFileContent;
BOOL  bResults = FALSE;
HINTERNET  hSession = NULL, 
           hConnect = NULL,
           hRequest = NULL;

// Use WinHttpOpen to obtain a session handle.
hSession = WinHttpOpen( L"WinHTTP Example/1.0",  
                        WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
                        WINHTTP_NO_PROXY_NAME, 
                        WINHTTP_NO_PROXY_BYPASS, 0);

// Specify an HTTP server.
if (hSession)
    hConnect = WinHttpConnect( hSession, L"nytimes.com",
                               INTERNET_DEFAULT_HTTP_PORT, 0);

// Create an HTTP request handle.
if (hConnect)
    hRequest = WinHttpOpenRequest( hConnect, L"GET", L"/ref/multimedia/podcasts.html",
                                   NULL, WINHTTP_NO_REFERER, 
              NULL, 
                                   NULL);

// Send a request.
if (hRequest)
    bResults = WinHttpSendRequest( hRequest,
                                   WINHTTP_NO_ADDITIONAL_HEADERS,
                                   0, WINHTTP_NO_REQUEST_DATA, 0, 
                                   0, 0);


// End the request.
if (bResults)
    bResults = WinHttpReceiveResponse( hRequest, NULL);

// Keep checking for data until there is nothing left.
if (bResults)
    do 
    {

        // Check for available data.
        dwSize = 0;
        if (!WinHttpQueryDataAvailable( hRequest, &dwSize))
            printf( "Error %u in WinHttpQueryDataAvailable.\n",
                    GetLastError());

        // Allocate space for the buffer.
        pszOutBuffer = new char[dwSize+1];
        if (!pszOutBuffer)
        {
            printf("Out of memory\n");
            dwSize=0;
        }
        else
        {
            // Read the Data.
            ZeroMemory(pszOutBuffer, dwSize+1);

            if (!WinHttpReadData( hRequest, (LPVOID)pszOutBuffer, 
                                  dwSize, &dwDownloaded))
      {
                printf( "Error %u in WinHttpReadData.\n", 
                        GetLastError());
      }
            else
      {
                     printf("%s", pszOutBuffer);
                            // Data in vFileContent
       vFileContent.push_back(pszOutBuffer);
      }

            // Free the memory allocated to the buffer.
            delete [] pszOutBuffer;
        }

    } while (dwSize>0);


// Report any errors.
if (!bResults)
    printf("Error %d has occurred.\n",GetLastError());

// Close any open handles.
if (hRequest) WinHttpCloseHandle(hRequest);
if (hConnect) WinHttpCloseHandle(hConnect);
if (hSession) WinHttpCloseHandle(hSession);

// Write vFileContent to file
ofstream out("test.txt",ios::binary);
for (int i = 0; i < (int) vFileContent.size();i++)
out << vFileContent[i];
out.close();

When I try to download a picture, I get only the first lines of the file and no error message. The problem seems related to this parameter (ppwszAcceptTypes) in WinHttpOpenRequest Function.

link text

A: 

Looks like this thread on MSDN is the same and has the solution

http://social.msdn.microsoft.com/forums/en-US/vclanguage/thread/45ccd91c-6794-4f9b-8f4f-865c76cc146d

Lou Franco
I've read this thread before, but the solution (opening the file in binary mode) didn't work for me. But I've just retried it, this time using C, not C++, and it works. So ofstream is not working with WinHttp, as far as I can tell.
A: 

Solution :

FILE * pFile; // NEW
pFile = fopen("file.bin", "w+b"); // NEW

if (bResults)
    do 
    {
        // Check for available data.
        dwSize = 0;
        if (!WinHttpQueryDataAvailable( hRequest, &dwSize))
            printf( "Error %u in WinHttpQueryDataAvailable.\n",
                    GetLastError());

        // Allocate space for the buffer.
        pszOutBuffer = new char[dwSize+1];



        if (!pszOutBuffer)
        {
            printf("Out of memory\n");
            dwSize=0;
        }
        else
        {
            // Read the Data.
            ZeroMemory(pszOutBuffer, dwSize+1);

            if (!WinHttpReadData( hRequest, (LPVOID)pszOutBuffer, 
                                  dwSize, &dwDownloaded))
      {
                printf( "Error %u in WinHttpReadData.\n", 
                        GetLastError());
      }
            else
      {
                            printf("%s", pszOutBuffer);
       fwrite(pszOutBuffer, (size_t)dwDownloaded, (size_t)1, pFile); // NEW

      }

            // Free the memory allocated to the buffer.
            delete [] pszOutBuffer;
        }

    } while (dwSize>0);

fclose (pFile); // NEW
+2  A: 

Merely opening the ofstream in binary mode does not change the way that the << operators work - they will always perfform formatted output. You need to use the stream's write() function, which does unformatted output.

anon