How do I configure WinHTTP Tracing programmatically? - c

Question

I have a C application (not C++ or C#) that tests connectivity to our API from a client's perspective using WinHTTP. Here's code that downloads a file.
DWORD Measure(FILE* fout, LPCTSTR lpszUrl) {
int i;
DWORD dwResult = 0;
DWORD dwSize = 0;
DWORD dwDownloaded = 0;
DWORD dwRequestSize = 0;
LPSTR pszOutBuffer;
BOOL bResults = FALSE;
HINTERNET hSession = NULL;
HINTERNET hConnect = NULL;
HINTERNET hRequest = NULL;
WINHTTP_STATUS_CALLBACK status = NULL;
if (0 == dwResult) {
hSession = WinHttpOpen(_T("Test/1.0"), WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
if (hSession == NULL) {
dwResult = GetLastError();
}
}
if (0 == dwResult) {
status = WinHttpSetStatusCallback(hSession, (WINHTTP_STATUS_CALLBACK)HttpCallback, WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS, NULL);
if (WINHTTP_INVALID_STATUS_CALLBACK == status) {
dwResult = GetLastError();
}
}
if (0 == dwResult) {
hConnect = WinHttpConnect(hSession, lpszUrl, INTERNET_DEFAULT_HTTPS_PORT, 0);
if (hConnect == NULL) {
dwResult = GetLastError();
}
}
if (0 == dwResult) {
hRequest = WinHttpOpenRequest(hConnect, L"GET", NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE | WINHTTP_FLAG_REFRESH);
if (hRequest == NULL) {
dwResult = GetLastError();
}
}
if (0 == dwResult) {
bResults = WinHttpSendRequest(hRequest,WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
}
if (0 == dwResult) {
if(!QueryPerformanceCounter(&liDownloadStart)){
dwResult = GetLastError();
}
}
if (bResults) {
bResults = WinHttpReceiveResponse(hRequest, NULL);
if (!bResults) {
dwResult = GetLastError();
}
}
if (dwResult == 0 && bResults) {
do {
dwSize = 0;
if( !WinHttpQueryDataAvailable( hRequest, &dwSize ) ){
dwResult = GetLastError();
}
if (0 == dwResult) {
dwRequestSize += dwSize;
}
pszOutBuffer = (LPSTR)malloc(dwSize+1);
if (!pszOutBuffer) {
dwResult = ERROR_OUTOFMEMORY;
}
if (dwResult == 0) {
ZeroMemory(pszOutBuffer, dwSize + 1);
if( !WinHttpReadData( hRequest, (LPVOID)pszOutBuffer, dwSize, &dwDownloaded ) ){
dwResult = GetLastError();
}
free(pszOutBuffer);
}
} while (dwSize > 0 && dwResult == 0);
}
if (hRequest) WinHttpCloseHandle(hRequest);
if (hConnect) WinHttpCloseHandle(hConnect);
if (hSession) WinHttpCloseHandle(hSession);
return dwResult;
}
I can enable tracing using the following module:
BOOL enable = TRUE;
WinHttpSetOption(NULL, WINHTTP_OPTION_ENABLETRACING, &enable, sizeof(enable));
Following the instructions in the article Capturing WinHTTP Logs, I could ask the user to enable tracing, including the path where files should be stored.
netsh winhttp set tracing trace-file-prefix="C:\Temp\dpws" level=verbose format=ansi state=enabled max-trace-file-size=1073741824
However, most folks running my application are technically challenged. They may forget to disable it when they are done.
How do I programmatically enable WinHTTP tracing for my process?