Question

I am creating an application in VC++ using win32,wininet to upload an image to Flickr.I am able to get Frob,Token correctly but when I try to upload the image I am getting error Post size too large.

Headers are created as follows

 wstring wstrAddHeaders = L"Content-Type: multipart/form-data;boundary=ABCD\r\n";
    wstrAddHeaders         += L"Host: api.flickr.com\r\n";
    wchar_t tempStr[MAX_PATH];
    wsprintf(L"Content-Length: %ld\r\n",szTotalSize);
    wstrAddHeaders         += tmpStr;
    wstrAddHeaders  +=L"\r\n";
HINTERNET hSession = InternetConnect(hInternet, L"www.flickr.com", INTERNET_DEFAULT_HTTP_PORT, NULL,NULL, INTERNET_SERVICE_HTTP, 0, 0);             
    if(hSession==NULL)
    {
        dwErr = GetLastError();
        return;
    }

Content of Post request are created as follows:

wstring wstrBoundry = L"--ABCD\r\n";

wstring wstrContent =wstrBoundry;
wstrContent +=L"Content-Disposition: form-data; name=\"api_key\"\r\n\r\n";
wstrContent +=wstrAPIKey.c_str() ;
wstrContent += L"\r\n";

wstrContent +=wstrBoundry;
wstrContent +=L"Content-Disposition: form-data; name=\"auth_token\"\r\n\r\n";
wstrContent +=m_wstrToken.c_str();
wstrContent += L"\r\n";

wstrContent +=wstrBoundry;
wstrContent +=L"Content-Disposition: form-data; name=\"api_sig\"\r\n\r\n";
wstrContent +=wstrSig;
wstrContent += L"\r\n";

wstrContent +=wstrBoundry;
wstrContent +=L"Content-Disposition: form-data; name=\"photo\"; filename=\"C:\\test.jpg\"";
wstrContent +=L"\r\n";
wstrContent +=L"Content-Type: image/jpeg\r\n\r\n";

wstring wstrFilePath(L"C:\\test.jpg");
CAtlFile file;

HRESULT hr = S_OK;
hr = file.Create(wstrFilePath.c_str(),GENERIC_READ,FILE_SHARE_READ,OPEN_EXISTING);
if(FAILED(hr))
{
    return;
}

ULONGLONG nLen;
hr = file.GetSize(nLen);

if (nLen > (DWORD)-1)
{
     return ;
}
char * fileBuf = new char[nLen];
file.Read(fileBuf,nLen);

wstring wstrLastLine(L"\r\n--ABCD--\r\n");

size_t szTotalSize =  sizeof(wchar_t) * (wstrContent.length()) +sizeof(wchar_t) * (wstrLastLine.length()) + nLen;
unsigned  char *buffer = (unsigned char *)malloc(szTotalSize);
memset(buffer,0,szTotalSize);


memcpy(buffer,wstrContent.c_str(),wstrContent.length() * sizeof(wchar_t));
memcpy(buffer+wstrContent.length() * sizeof(wchar_t),fileBuf,nLen);
memcpy(buffer+wstrContent.length() * sizeof(wchar_t)+nLen,wstrLastLine.c_str(),wstrLastLine.length() * sizeof(wchar_t));

hRequest =  HttpOpenRequest(hSession, L"POST", L"/services/upload/", L"HTTP/1.1", NULL, NULL, 0, NULL);
if(hRequest)
{
    bRet = HttpAddRequestHeaders(hRequest,wstrAddHeaders.c_str(),wstrAddHeaders.length(),HTTP_ADDREQ_FLAG_ADD | HTTP_ADDREQ_FLAG_REPLACE);
    if(bRet)
    {
        bRet  = HttpSendRequest(hRequest,NULL,0,(void *)buffer,szTotalSize);
        if(bRet)
        {
            while(true)         
                {   
                    char buffer[1024]={0};
                    DWORD read=0;
                    BOOL r = InternetReadFile(hRequest,buffer,1024,&read);
                    if(read !=0) 
                    {
                        wstring strUploadXML =buffer;
                        break;
                    }
                }
        }

    }

I am not pretty sure the way I am adding image data to the string and posting the request.
Do I need to convert image data into Unicode?
Any suggestions , if someone can find what I am doing wrong that would be very helpful to me.

Answer 1

Actually we cannot send Post content as unicode.
We can use headers as unicode in Wininet APIs .

Once we read the image data in char * buffer , we can add that buffer into post content string and then add the last line of content.