C++ WinHttp get response header and body - c++

Question

I'm currently trying to write a class to make sending simple requests easier for me.
In the end I'd like it to be usable somewhat like this:
int _tmain(int argc, _TCHAR* argv[])
{
HttpRequest Request(L"Example UserAgent/1.0",L"",L"");
Request.SendRequest(L"google.com",L"GET",NULL);
if (Request.responseHeader)
printf("%s",Request.responseHeader);
if (Request.responseBody)
printf("%s",Request.responseBody);
getchar();
return 0;
}
But for now it doesn't work at all. I have no idea how I could get the response header and I'm failing writing the response header to a public member of my class.
Yeah I'm really bad at C++ especially when it's about the winapi.
Well I hope you can help me out.
Here is my code so far:
#include "stdafx.h"
#include <windows.h>
#include <winhttp.h>
#pragma comment(lib, "winhttp.lib")
class HttpRequest {
private:
DWORD dwSize;
DWORD dwDownloaded;
LPSTR pszOutBuffer;
BOOL bResults;
HINTERNET hSession;
HINTERNET hConnect;
HINTERNET hRequest;
LPCWSTR _userAgent;
//LPCWSTR _proxyIp;
//LPCWSTR _proxyPort;
size_t bodySize;
public:
HttpRequest(LPCWSTR, LPCWSTR, LPCWSTR);
void SendRequest(LPCWSTR, LPCWSTR, LPVOID);
LPSTR responseHeader[1000000];
LPSTR responseBody[1000000];
};
HttpRequest::HttpRequest(LPCWSTR userAgent, LPCWSTR proxyIp, LPCWSTR proxyPort) {
_userAgent = userAgent;
//_proxyIp = proxyIp;
//_proxyPort = proxyPort;
hSession = WinHttpOpen( userAgent, WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0 );
}
void HttpRequest::SendRequest(LPCWSTR url, LPCWSTR method, LPVOID body) {
bodySize = 0;
if (hSession)
hConnect = WinHttpConnect( hSession, url, INTERNET_DEFAULT_HTTPS_PORT, 0 );
else
printf("session handle failed\n");
if (hConnect)
hRequest = WinHttpOpenRequest( hConnect, method, NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE );
else
printf("connect handle failed\n");
if (hRequest)
bResults = WinHttpSendRequest( hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, body, 0, 0, 0 );
else
printf("request handle failed\n");
if( bResults )
bResults = WinHttpReceiveResponse( hRequest, NULL );
if( bResults )
{
do
{
// Check for available data.
dwSize = 0;
if( !WinHttpQueryDataAvailable( hRequest, &dwSize ) )
printf( "Error %u in WinHttpQueryDataAvailable.\n", GetLastError( ) );
// Allocate space for the buffer.
pszOutBuffer = new char[dwSize+1];
if( !pszOutBuffer )
{
printf( "Out of memory\n" );
dwSize=0;
}
else
{
// Read the data.
ZeroMemory( pszOutBuffer, dwSize+1 );
if( !WinHttpReadData( hRequest, (LPVOID)pszOutBuffer, dwSize, &dwDownloaded ) )
printf( "Error %u in WinHttpReadData.\n", GetLastError( ) );
else {
//printf( "%s", pszOutBuffer );
responseBody[bodySize++] = pszOutBuffer;
}
// Free the memory allocated to the buffer.
delete [] pszOutBuffer;
}
} while( dwSize > 0 );
}
// Report any errors.
if( !bResults )
printf( "Error %d has occurred.\n", GetLastError( ) );
// Close any open handles.
if( hRequest ) WinHttpCloseHandle( hRequest );
if( hConnect ) WinHttpCloseHandle( hConnect );
if( hSession ) WinHttpCloseHandle( hSession );
}

Answer 1

Use WinHttpQueryHeaders() to access the response headers. Use the WINHTTP_QUERY_RAW_HEADERS(_CRLF) flag to specify that you want to retrieve all of the available headers.
You also need to change your class to dynamically allocate its responseHeader and responseBody members. You are wasting a lot of memory, as well as limiting the response size you can handle, by using static arrays.
Try this:
#include "stdafx.h"
#include <windows.h>
#include <winhttp.h>
#include <string>
#include <vector>
#pragma comment(lib, "winhttp.lib")
class HttpRequest
{
private:
std::wstring _userAgent;
//std::wstring _proxyIp;
//std::wstring _proxyPort;
public:
HttpRequest(const std::wstring&, const std::wstring&, const std::wstring&);
bool SendRequest(const std::wstring&, const std::wstring&, void*, DWORD);
std::wstring responseHeader;
std::vector<BYTE> responseBody;
};
HttpRequest::HttpRequest(const std::wstring &userAgent, const std::wstring &proxyIp, const std::wstring &proxyPort) :
_userAgent(userAgent)
//,_proxyIp(proxyIp)
//,_proxyPort(proxyPort)
{
}
bool HttpRequest::SendRequest(const std::wstring &url, const std::wstring &method, void *body, DWORD bodySize)
{
DWORD dwSize;
DWORD dwDownloaded;
DWORD headerSize = 0;
BOOL bResults = FALSE;
HINTERNET hSession;
HINTERNET hConnect;
HINTERNET hRequest;
responseHeader.resize(0);
responseBody.resize(0);
hSession = WinHttpOpen( _userAgent.c_str(), WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0 );
if (hSession)
hConnect = WinHttpConnect( hSession, url.c_str(), INTERNET_DEFAULT_HTTPS_PORT, 0 );
else
printf("session handle failed\n");
if (hConnect)
hRequest = WinHttpOpenRequest( hConnect, method.c_str(), NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE );
else
printf("connect handle failed\n");
if (hRequest)
bResults = WinHttpSendRequest( hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, body, bodySize, 0, 0 );
else
printf("request handle failed\n");
if (bResults)
bResults = WinHttpReceiveResponse( hRequest, NULL );
if (bResults)
{
bResults = WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_RAW_HEADERS_CRLF, NULL, WINHTTP_NO_OUTPUT_BUFFER, &headerSize, WINHTTP_NO_HEADER_INDEX);
if ((!bResults) && (GetLastError() == ERROR_INSUFFICIENT_BUFFER))
{
responseHeader.resize(headerSize / sizeof(wchar_t));
if (responseHeader.empty())
{
bResults = TRUE;
}
else
{
bResults = WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_RAW_HEADERS_CRLF, NULL, &responseHeader[0], &headerSize, WINHTTP_NO_HEADER_INDEX);
if( !bResults ) headerSize = 0;
responseHeader.resize(headerSize / sizeof(wchar_t));
}
}
}
if (bResults)
{
do
{
// Check for available data.
dwSize = 0;
bResults = WinHttpQueryDataAvailable( hRequest, &dwSize );
if (!bResults)
{
printf( "Error %u in WinHttpQueryDataAvailable.\n", GetLastError( ) );
break;
}
if (dwSize == 0)
break;
do
{
// Allocate space for the buffer.
DWORD dwOffset = responseBody.size();
responseBody.resize(dwOffset+dwSize);
// Read the data.
bResults = WinHttpReadData( hRequest, &responseBody[dwOffset], dwSize, &dwDownloaded );
if (!bResults)
{
printf( "Error %u in WinHttpReadData.\n", GetLastError( ) );
dwDownloaded = 0;
}
responseBody.resize(dwOffset+dwDownloaded);
if (dwDownloaded == 0)
break;
dwSize -= dwDownloaded;
}
while (dwSize > 0);
}
while (true);
}
// Report any errors.
if (!bResults)
printf( "Error %d has occurred.\n", GetLastError( ) );
// Close any open handles.
if( hRequest ) WinHttpCloseHandle( hRequest );
if( hConnect ) WinHttpCloseHandle( hConnect );
if( hSession ) WinHttpCloseHandle( hSession );
return bResults;
}
int _tmain(int argc, _TCHAR* argv[])
{
HttpRequest Request(L"Example UserAgent/1.0",L"",L"");
if (Request.SendRequest(L"google.com",L"GET",NULL,0))
{
printf("%ls",Request.responseHeader.c_str());
if (!Request.responseBody.empty())
printf("%*s",Request.responseBody.size(),(char*)&Request.responseBody[0]);
}
getchar();
return 0;
}