data download with set user-agent c++ - c++

Question

I have a function to upload information to a byte array, but it ends with - if (!Httpsendrequest(httprequest, szHeaders, strlen(szhheaders), szRequest, strlen(szRequest)))
string GetUrlData(const string& url, LPCSTR host, string& output)
{
string request_data = "";
output = "";
HINTERNET hIntSession = InternetOpenA("token", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
if (!hIntSession)
{
return request_data;
}
HINTERNET hHttpSession = InternetConnectA(hIntSession, host, 80, 0, 0, INTERNET_SERVICE_HTTP, 0, NULL);
if (!hHttpSession)
{
return request_data;
}
HINTERNET hHttpRequest = HttpOpenRequestA(hHttpSession, "GET", url.c_str()
, 0, 0, 0, INTERNET_FLAG_RELOAD, 0);
if (!hHttpSession)
{
return request_data;
}
char* szHeaders = ("Content-Type: text/html\r\nUser-Agent: License");
char szRequest[1024] = { 0 };
if (!HttpSendRequestA(hHttpRequest, szHeaders, strlen(szHeaders), szRequest, strlen(szRequest)))
{
qDebug()<<"BLYA";
return request_data;
}
CHAR szBuffer[1024] = { 0 };
DWORD dwRead = 0;
while (InternetReadFile(hHttpRequest, szBuffer, sizeof(szBuffer) - 1, &dwRead) && dwRead)
{
request_data.append(szBuffer, dwRead);
}
InternetCloseHandle(hHttpRequest);
InternetCloseHandle(hHttpSession);
InternetCloseHandle(hIntSession);
output = request_data;
}

Answer 1

The failure might have something to do with the fact that szHeaders is missing \r\n on the User-Agent header. Every header you send ust be terminated with \r\n. And BTW, there is no reason to send a Content-Type header in a GET request, since there is no message body being sent to the server.
Also, your code has a bunch of memory leaks if anything goes wrong. You need to close every handle you successfully open.
Also, there is no point in having both a return value and an output parameter that return the same data. Pick one or the other. I would suggest using a bool return value and a string output parameter.
Try something more like this:
bool GetUrlData(const string& resource, const string& host)
{
output.clear();
bool result = false;
HINTERNET hIntSession = InternetOpenA("token", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
if (!hIntSession) {
qDebug() << "InternetOpen failed, error: " << GetLastError();
return false;
}
HINTERNET hHttpSession = InternetConnectA(hIntSession, host.c_str(), 80, 0, 0, INTERNET_SERVICE_HTTP, 0, NULL);
if (!hHttpSession) {
qDebug() << "InternetConnect failed, error: " << GetLastError();
InternetCloseHandle(hIntSession);
return false;
}
HINTERNET hHttpRequest = HttpOpenRequestA(hHttpSession, "GET", resource.c_str(), 0, 0, 0, INTERNET_FLAG_RELOAD, 0);
if (!hHttpRequest) {
qDebug() << "HttpOpenRequest failed, error: " << GetLastError();
InternetCloseHandle(hHttpSession);
InternetCloseHandle(hIntSession);
return false;
}
const char* szHeaders = "User-Agent: License\r\n";
if (!HttpSendRequestA(hHttpRequest, szHeaders, -1, NULL, 0)) {
qDebug() << "HttpSendRequest failed, error: " << GetLastError();
InternetCloseHandle(hHttpRequest);
InternetCloseHandle(hHttpSession);
InternetCloseHandle(hIntSession);
return false;
}
char szBuffer[1024];
DWORD dwRead = 0;
do {
if (!InternetReadFile(hHttpRequest, szBuffer, sizeof(szBuffer), &dwRead)) {
qDebug() << "InternetReadFile failed, error: " << GetLastError();
InternetCloseHandle(hHttpRequest);
InternetCloseHandle(hHttpSession);
InternetCloseHandle(hIntSession);
return false;
}
if (dwRead == 0)
break;
output.append(szBuffer, dwRead);
}
while (true);
return true;
}