Problem - Kevin Tafuro

DWORD dwHeadersLength = 0;
LPSTR lpszOptional = 0;
DWORD dwOptionalLength = 0;
bResult = HttpSendRequest(hRequest, lpszHeaders, dwHeadersLength, lpOptional,
dwOptionalLength);
After sending the request, the server’s response can be retrieved. As part of sending
the request, WinInet will retrieve the response headers from the server. Information
about the response can be obtained using the HttpQueryInfo( ) function. A complete
list of the information that may be available can be found in the WinInet documentation,
but for our purposes, the only information we’re concerned with is the content
length. The server is not required to send a content length header back as part of its
response, so we must also be able to handle the case where it is not sent. Response
data sent by the server after its response headers can be obtained by calling
InternetReadFile( ) as many times as necessary to retrieve all of the data.
DWORD dwContentLength, dwIndex, dwInfoLevel;
DWORD dwBufferLength, dwNumberOfBytesRead, dwNumberOfBytesToRead;
LPVOID lpBuffer, lpFullBuffer, lpvBuffer;
dwInfoLevel = HTTP_QUERY_CONTENT_LENGTH;
lpvBuffer = (LPVOID)&dwContentLength;
dwBufferLength = sizeof(dwContentLength);
dwIndex = 0;
HttpQueryInfo(hRequest, dwInfoLevel, lpvBuffer, &dwBufferLength, &dwIndex);
if (dwIndex != ERROR_HTTP_HEADER_NOT_FOUND) {
/* Content length is known. Read only that much data. */
lpBuffer = GlobalAlloc(GMEM_FIXED, dwContentLength);
InternetReadFile(hRequest, lpBuffer, dwContentLength, &dwNumberOfBytesRead);
} else {
/* Content length is not known. Read until EOF is reached. */
dwContentLength = 0;
dwNumberOfBytesToRead = 4096;
lpFullBuffer = lpBuffer = GlobalAlloc(GMEM_FIXED, dwNumberOfBytesToRead);
while (InternetReadFile(hRequest, lpBuffer, dwNumberOfBytesToRead,
&dwNumberOfBytesRead)) {
dwContentLength += dwNumberOfBytesRead;
if (dwNumberOfBytesRead != dwNumberOfBytesToRead) break;
lpFullBuffer = GlobalReAlloc(lpFullBuffer, dwContentLength +
dwNumberOfBytesToRead, 0);
lpBuffer = (LPVOID)((LPBYTE)lpFullBuffer + dwContentLength);
}
lpFullBuffer = lpBuffer = GlobalReAlloc(lpFullBuffer, dwContentLength, 0);
}
After the data has been read with InternetReadFile( ), the variable lpBuffer will hold
the contents of the server’s response, and the variable dwContentLength will hold the
number of bytes contained in the response data buffer. At this point, the request has
been completed, and the request object should be destroyed by calling
InternetCloseHandle( ). If additional requests to the same connection are required, a
Securing Web Communication on Windows Using the WinInet API | 467
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