How to make HTTPS calls (POST requests) using WinHTTP on C++? - c++

Question

I'm writing program on C++ to make calls (POST requests) to Java Servlets using WinHTTP. When I request POST via HTTP everything is OK, problem occurs when I request via HTTPS. It sends empty requests to the server but cuts off request body (but it has content)
int sendPostRequest(char *pszPostData, LPCTSTR servletUrl, char* resultBuffer, ofstream &outputFile) {
outputFile << "====================================== SENDING REEQUEST ======================================" << endl;
HINTERNET hSession = WinHttpOpen(
userAgent,
WINHTTP_ACCESS_TYPE_NO_PROXY,
WINHTTP_NO_PROXY_NAME,
WINHTTP_NO_PROXY_BYPASS,
0);
if (!hSession)
{
_tprintf(_TEXT("Failed to open WinHTTP session: %ld\n"), GetLastError());
outputFile << "Failed to open WinHTTP session: %ld\n" << GetLastError() << endl;
return NULL;
}
else {
_tprintf(_TEXT("Oppening WinHTTP session successful: %ld\n"), GetLastError());
outputFile << "Oppening WinHTTP session successful: %ld\n" << GetLastError() << endl;
}
HINTERNET hConnect = WinHttpConnect(
hSession,
serverIP,
serverPort,
0);
if (!hConnect)
{
_tprintf(_TEXT("Failed to connect to server: %ld\n"), GetLastError());
outputFile << "Failed to connect to server: %ld\n" << GetLastError() << endl;
WinHttpCloseHandle(hSession);
return NULL;
}
else {
_tprintf(_TEXT("Connection to server successful: %ld\n"), GetLastError());
outputFile << "Connection to server successful: %ld\n" << GetLastError() << endl;
}
_tprintf(_TEXT("Post data : %ld\n"), pszPostData);
outputFile << "Post data : %ld\n" << pszPostData << endl;
DWORD dwDataLen = strlen(pszPostData);
HINTERNET hRequest = WinHttpOpenRequest(
hConnect,
_TEXT("POST"),
servletUrl,
NULL,
WINHTTP_NO_REFERER,
WINHTTP_DEFAULT_ACCEPT_TYPES,
WINHTTP_FLAG_REFRESH);
if (!hRequest)
{
_tprintf(_TEXT("Failed to open request: %ld\n"), GetLastError());
outputFile << "Failed to open request: %ld\n" << GetLastError() << endl;
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
return -1;
}
else {
_tprintf(_TEXT("Opening request successful: %ld\n"), GetLastError());
outputFile << "Opening request successful: %ld\n" << GetLastError() << endl;
}
DWORD dwReqOpts = 0;
DWORD dwSize = sizeof(DWORD);
WinHttpSetOption(
hRequest,
WINHTTP_OPTION_SECURITY_FLAGS,
&dwReqOpts,
sizeof(DWORD));
BOOL done = false;
BOOL rc = WinHttpSendRequest(
hRequest,
contentTypeHeader,
-1,
(LPVOID)pszPostData,
dwDataLen,
dwDataLen,
NULL);
if (rc) {
rc = WinHttpReceiveResponse(hRequest, NULL);
_tprintf(_TEXT("Sending request successful: %ld\n"), GetLastError());
outputFile << "Sending request successful: %ld\n" << GetLastError() << endl;
}
else
{
_tprintf(_TEXT("Send request failed: %ld\n"), GetLastError());
outputFile << "Send request failed: %ld\n" << GetLastError() << endl;
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
return -1;
}
// Get the status from the server
DWORD dwCode = 0;
if (rc)
{
rc = WinHttpQueryHeaders(
hRequest,
WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER,
NULL,
&dwCode,
&dwSize,
NULL);
}
if (dwCode != HTTP_STATUS_OK)
{
_tprintf(_TEXT("HTTP Request failed: %ld\n"), dwCode);
outputFile << "HTTP Request failed: %ld\n" << dwCode << endl;
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
}
else
{
_tprintf(_TEXT("HTTP Request is ok: %ld\n"), dwCode);
outputFile << "HTTP Request is ok : %ld\n" << dwCode << endl;
// Keep reading from the remote server until there's nothing left to read
DWORD dwBytesToBeRead = 0, dwBytesRead = 0;
//char szBuffer[8192] = { 0 };
//strcpy(resultBuffer, "");
do
{
if (!WinHttpQueryDataAvailable(hRequest, &dwBytesToBeRead))
{
_tprintf(_TEXT("No data available from server? %ld"), GetLastError());
outputFile << "No data available from server? %ld" << GetLastError() << endl;
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
return -1;
}
if (!WinHttpReadData(
hRequest,
//szBuffer,
resultBuffer,
//sizeof(szBuffer),
RESULT_BUFFER_SIZE,
&dwBytesRead))
{
_tprintf(_TEXT("Failed to read data from server: %ld"), GetLastError());
outputFile << "Failed to read data from server: %ld" << GetLastError() << endl;
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
return -1;
}
if (dwBytesRead > 0)
{
//szBuffer[dwBytesRead] = 0;
resultBuffer[dwBytesRead] = 0; // NULL-terminated returned buffer
}
} while (dwBytesRead > 0);
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
return 0;
}
return -1;
}
Where pszPostData - content of request body, servletUrl - url to Servlet (endpoint), resultBuffer - call result will be written to this buffer, outputFile - file for logs.
So how to make HTTPS calls without cutting of request body?

Answer 1

Regarding WinHttpSendRequest method, at the 2nd paramaet insert: L"content-type:application/x-www-form-urlencoded" and on the 3rd paramer -1 which is according to w3.
It should work with this correction.
Also, check the encoding of your .php file, gave me a trouble once.

Answer 2

I came across this today as I was facing a very similar issue. In WinHttpConnect() I was sending pswzServerName as 'example.com'. Problem is, in Apache, I was forcing a redirect on domain.com to www.domain.com and also http to https. This redirect was causing no POST data to be sent, wrong content-length header, and wrong content-type header because I had specified example.com in WinHttpConnect().
Two solutions worked with the last being the best choice :
Removing my htaccess non-www to www and http to https redirect
OR
just changing `pswzServerName` to 'www.example.com' (including the www.) in WinHttpConnect()
Spent a long time trying to figure out why winhttp wasn't working as this was easily overlooked so hopefully it helps someone else that might be in the same boat.

Answer 3

Even if it is an old question, this might be helpful:
Add WINHTTP_FLAG_SECURE to the WinHttpOpenRequest, and it should work.
...
HINTERNET hRequest = WinHttpOpenRequest(
hConnect,
_TEXT("POST"),
servletUrl,
NULL,
WINHTTP_NO_REFERER,
WINHTTP_DEFAULT_ACCEPT_TYPES,
WINHTTP_FLAG_REFRESH+WINHTTP_FLAG_SECURE); /// Here
...