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I am trying to send and retrieve data to/from a remote client computer. I can't use DCOM or Named Pipes because ports 135 and 445 are closed and cannot be opened.
The advantage of winhttp, according to Microsoft docs, is you can use http as the transport (instead of named pipes) without having an IIS web server on the other end.
I'd consider using TCP, but I can't find any examples of using TCP in C/C++, and at this point I'm not sure if any exist?
I think I've got the basic connection down of the request, but how do I send information to the other computer? And how does the other server send it back?
Here's my code for doing a GET for Winhttp:
#include <windows.h>
#include <tchar.h>
#include <winhttp.h>
#include <strsafe.h>
#define tnew(nCharacters) new CHAR[nCharacters]()
#pragma comment(lib, "winhttp.lib")
int main()
{
CHAR *sResult = tnew(1024);
DWORD dwSize = 0, dwDownloaded = 0;
LPSTR pszOutBuffer = NULL;
BOOL bResults = FALSE;
HINTERNET hSession = NULL, hConnect = NULL, hRequest = NULL;
// Use WinHttpOpen to obtain a session handle.
hSession = WinHttpOpen(_T("WinHTTP Example/1.0"), WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
if (hSession)
hConnect = WinHttpConnect(hSession, L"www.microsoft.com", INTERNET_DEFAULT_HTTPS_PORT, 0); // Specify an HTTP server.
if (hConnect)
hRequest = WinHttpOpenRequest(hConnect, _T("GET"), NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE); // Create an HTTP request handle.
if (hRequest)
bResults = WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0); // Send a request.
if (bResults)
bResults = WinHttpReceiveResponse(hRequest, NULL); // End the request.
if (bResults) // Keep checking for data until there is nothing left.
{
do
{
dwSize = 0;
if (WinHttpQueryDataAvailable(hRequest, &dwSize)) // Check for available data.
{
pszOutBuffer = new CHAR[dwSize + 1];
ZeroMemory(pszOutBuffer, dwSize + 1);
if (WinHttpReadData(hRequest, (LPVOID)pszOutBuffer, dwSize, &dwDownloaded)) // Read the data.
StringCchPrintfA(sResult, 1024, "%s%s", sResult, pszOutBuffer);
}
}
while (dwSize > 0);
}
delete[] pszOutBuffer;
if (hRequest) WinHttpCloseHandle(hRequest);
if (hConnect) WinHttpCloseHandle(hConnect);
if (hSession) WinHttpCloseHandle(hSession);
}
I am trying to convert some HTTP request code from using the WinHttp COM interface to using lower-level WinInet calls from <wininet.h>. The COM version is working but I am having difficulty translating the calls into the WinInet API.
This code works fine and gets the correct error response (as the request data is empty) to the POST request:
#import <winhttpcom.dll>
#include <iostream>
#include <string>
int main()
{
HRESULT hr = CoInitialize(NULL);
using namespace WinHttp;
IWinHttpRequestPtr pReq = NULL;
hr = pReq.CreateInstance(__uuidof(WinHttpRequest));
const char* pszReq = "";
if (SUCCEEDED(hr))
{
_bstr_t bstrMethod("POST");
_bstr_t bstrUrl("https://lite.realtime.nationalrail.co.uk/OpenLDBWS/ldb9.asmx");
hr = pReq->Open(bstrMethod, bstrUrl);
pReq->SetRequestHeader(_bstr_t("Content-Type"), _bstr_t("text/*"));
_variant_t vReq(pszReq);
hr = pReq->Send(vReq);
if (SUCCEEDED(hr))
{
_bstr_t bstrResp;
hr = pReq->get_ResponseText(&bstrResp.GetBSTR());
if (SUCCEEDED(hr))
{
std::cout << std::string(bstrResp) << "\n";
}
}
}
CoUninitialize();
}
Saving the output as html, gives this rendering of the response (which is what I expect, since I haven't provided any request data, which would usually include an access token).
This is the code (amended after comments below, and should be reproducible) that I am using to try and replicate this result using wininet.h and the low-level Win32 calls (I realize I haven't closed the handles).
#include <windows.h>
#include <WinInet.h>
#include <iostream>
int main()
{
const char* pszReq = "";
const char* pszUrl = "https://lite.realtime.nationalrail.co.uk/OpenLDBWS/ldb9.asmx";
char szHostName[256];
char szPath[256];
URL_COMPONENTSA comps = {};
comps.dwStructSize = sizeof(comps);
comps.lpszHostName = szHostName;
comps.dwHostNameLength = sizeof(szHostName);
comps.lpszUrlPath = szPath;
comps.dwUrlPathLength = sizeof(szPath);
if (!InternetCrackUrlA(pszUrl, strlen(pszUrl), 0, &comps)) return 1;
HINTERNET hOpen = InternetOpenA("XYZ",INTERNET_OPEN_TYPE_DIRECT,NULL,NULL,0);
if (!hOpen) return 1;
HINTERNET hConnect = InternetConnectA(hOpen,szHostName,comps.nPort,
NULL,NULL,INTERNET_SERVICE_HTTP,0,NULL);
if (!hConnect) return 1;
const char * rgpszAcceptTypes[] = { "text/*", NULL };
HINTERNET hOpenReq = HttpOpenRequestA(hConnect,"POST",szPath,NULL, NULL,
rgpszAcceptTypes, 0,NULL);
if (!hOpenReq) return 1;
const char* pszHeader = "Content-Type: text/xml;charset=UTF-8";
//*** This line returns FALSE ***
BOOL bRet = HttpSendRequestA(hOpenReq, pszHeader, strlen(pszHeader), (LPVOID)pszReq, strlen(pszReq));
//*** LastError is ERROR_HTTP_INVALID_SERVER_RESPONSE
DWORD dwErr = GetLastError();
return 0;
}
All the WinInet handles are non-zero, suggesting the calls are working, but the last HttpSendRequestA() is returning FALSE immediately, with LastError set to ERROR_HTTP_INVALID_SERVER_RESPONSE.
Clearly the COM route hides a lot of intermediate working, and presumably some constants are defaulted to specific values. It may also be adding other header information, I suppose.
Perhaps someone can suggest where I am going wrong?
There are some mistakes in your WinInet code:
the pszServerName value needs to be just the host name by itself, not a full URL. If you have a URL as input, you can parse it into its constituent pieces using InternetCrackUrlA().
the 3rd parameter of HttpOpenRequestA() is the requested resource relative to pszServerName. So, in your example, you need to use "/" to request the root resource.
the 1st parameter of HttpSendRequestA() needs to be hOpenReq, not hOpen. Also, you should not be including the null-terminators in your buffer sizes.
If you have not already done so, you should have a look at WinInet's documentation on HTTP Sessions.
With that said, try this:
#include <windows.h>
#include <WinInet.h>
#include <iostream>
const char * pszUrl = "https://someUrl";
const char * pszReq = "A string of request data";
const char* pszHeader = "Content-Type: text/xml;charset=UTF-8";
char szHostName[256];
char szPath[256];
URL_COMPONENTSA comps = {};
comps.dwStructSize = sizeof(comps);
comps.lpszHostName = szHostName;
comps.dwHostNameLength = sizeof(szHostName);
comps.lpszUrlPath = szPath;
comps.dwUrlPathLength = sizeof(szPath);
BOOL bRet = InternetCrackUrlA(pszUrl, strlen(pszUrl), 0, &comps);
if (!bRet) ...
HINTERNET hOpen = InternetOpenA("XYZ", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
if (!hOpen) ...
HINTERNET hConnect = InternetConnectA(hOpen, szHostName, comps.nPort, NULL, NULL, INTERNET_SERVICE_HTTP, 0, NULL);
if (!hConnect) ...
HINTERNET hOpenReq = HttpOpenRequestA(hConnect, "POST", szPath, NULL, NULL, NULL, comps.nScheme == INTERNET_SCHEME_HTTPS ? INTERNET_FLAG_SECURE : 0, NULL);
if (!hOpenReq) ...
bRet = HttpSendRequestA(hOpenReq, pszHeader, strlen(pszHeader), pszReq, strlen(pszReq));
if (!bRet) ...
...
What HTTP header exactly can be queried using WINHTTP_QUERY_URI flag with WinHttpQueryHeaders function? After reading its description I was under impression this flag was supposed to be used to get the URI of the request specified in WinHttpOpenRequest function. Yet the following program gives me an error code 12019 ERROR_INTERNET_INCORRECT_HANDLE_STATE (and 12150 ERROR_HTTP_HEADER_NOT_FOUND if I uncomment two commented lines).
#include <cstdio>
#include <windows.h>
#include <winhttp.h>
#pragma comment(lib, "winhttp.lib")
int main()
{
HINTERNET hSession = WinHttpOpen(nullptr, WINHTTP_ACCESS_TYPE_NO_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
HINTERNET hConnect = WinHttpConnect(hSession, L"www.ietf.org", INTERNET_DEFAULT_HTTP_PORT, 0);
HINTERNET hRequest = WinHttpOpenRequest(hConnect, L"GET", L"/rfc/rfc2616.txt", nullptr, WINHTTP_NO_REFERER, nullptr, 0);
//WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
//WinHttpReceiveResponse(hRequest, 0);
wchar_t url[1024] = {};
DWORD url_size = sizeof(url);
auto success = WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_URI, WINHTTP_HEADER_NAME_BY_INDEX, url, &url_size, WINHTTP_NO_HEADER_INDEX);
auto error_code = GetLastError();
wprintf(L"success=%d error_code=%u url=%s", success, error_code, url);
WinHttpCloseHandle(hRequest);
WinHttpCloseHandle(hConnect);
WinHttpCloseHandle(hSession);
}
P.S. Yes, I know I can get request URI using WinHttpQueryOption and WINHTTP_OPTION_URL, no need to point that out.
EDIT. Adding WINHTTP_QUERY_FLAG_REQUEST_HEADERS flag as per Captain Obvlious answer below (which totally makes sense if WINHTTP_QUERY_URI was indeed supposed to return request URI) did not make much difference: now with or without WinHttpSendRequest and WinHttpReceiveResponse calls WinHttpQueryHeaders function produces error code 12150 ERROR_HTTP_HEADER_NOT_FOUND.
You are querying the response headers of the request which do not contain the URI. You need to include the WINHTTP_QUERY_FLAG_REQUEST_HEADERS modifier flag to retrieve from the request header.
WinHttpQueryHeaders(
hRequest,
WINHTTP_QUERY_URI | WINHTTP_QUERY_FLAG_REQUEST_HEADERS,
WINHTTP_HEADER_NAME_BY_INDEX,
url,
&url_size,
WINHTTP_NO_HEADER_INDEX);
I am trying to connect and ensure various pages exist on a webserver provided by an instrument we design. I am trying to do this through C++ Win32 using WinInet commands.
I am happy that I have connected correctly to the webserver via HTTP:
hInternet = InternetOpen("Test", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0/*INTERNET_FLAG_ASYNC*/);
hhttp = InternetConnect(hInternet, "192.168.111.222", INTERNET_DEFAULT_HTTP_PORT, "admin", "admin", INTERNET_SERVICE_HTTP, 0, 0);
I believe I then have to open a request.
hHttpRequest = HttpOpenRequest(hhttp, "GET", "galogo.png", NULL, "192.168.111.222", lplpszAcceptTypes, INTERNET_FLAG_RELOAD | INTERNET_FLAG_PRAGMA_NOCACHE, 0);
and then send the request.
HttpSendRequest(hHttpRequest, NULL, 0, NULL, 0)
Note: 192.168.111.222 is the address of the unit running the webserver and galogo.png is an image displayed on the home page. Please also note that I am error checking between each statements so if I do disconnect the Ethernet then I do get a failure.
Initially I did try just connecting to the home.html page but this always passed so I thought I should try and get the image but I am probably lacking in knowledge. Other examples seem to then stream data but I wasn't sure if I needed to do this.
Most of the examples I have seen seem to show the HtppSendRequest in this format and I don't really understand about headers etc. Maybe it is here I am going wrong.
The HttpQueryInfo function will give header information relating to the request, and you can extract the HTTP status code from this.
You may be able to achieve the result more easily using higher level WinINet functions. I would suggest a sequence consisting of InternetOpen, InternetOpenUrl, HttpQueryInfo and then repeated calls to InternetReadFile if the HTTP status code is OK.
This Delphi code (from Delphi 7, so pre-Unicode) seems to do the job: -
function GetUrlContent(const Agent, Url: string): string;
var
NetHandle: HINTERNET;
UrlHandle: HINTERNET;
Buffer: array [0..1024] of Char;
BytesRead: DWORD;
Dummy: DWORD;
BufLen: DWORD;
HttpStatus: string;
begin
Result := '';
NetHandle := InternetOpen(PChar(Agent), INTERNET_OPEN_TYPE_PRECONFIG,
nil, nil, 0);
if Assigned(NetHandle) then
begin
UrlHandle := InternetOpenUrl(NetHandle, PChar(Url), nil, 0,
INTERNET_FLAG_RELOAD, 0);
if Assigned(UrlHandle) then
// UrlHandle valid? Proceed with download.
try
BufLen := Length(Buffer);
Dummy := 0;
// only get the file if the HTTP status code is 200
if HttpQueryInfo(UrlHandle, HTTP_QUERY_STATUS_CODE, #Buffer[0], BufLen, Dummy) then
begin
HttpStatus := Buffer;
if HttpStatus = '200' then
begin
FillChar(Buffer, SizeOf(Buffer), 0);
repeat
Result := Result + Buffer;
FillChar(Buffer, SizeOf(Buffer), 0);
InternetReadFile(UrlHandle, #Buffer, SizeOf(Buffer), BytesRead);
until BytesRead = 0;
end
else begin
raise Exception.CreateFmt('HTTP status code %s', [HttpStatus]);
end;
end
else begin
raise Exception.Create('Unable to read HTTP status code');
end;
finally
InternetCloseHandle(UrlHandle);
end
else begin
// UrlHandle is not valid. Raise an exception.
raise Exception.CreateFmt('Cannot open URL %s', [Url]);
end;
InternetCloseHandle(NetHandle);
end
else begin
// NetHandle is not valid. Raise an exception.
raise Exception.Create('Unable to initialize WinINet');
end;
end;
So, using a combination of cURL and Wireshark I'm finally there. I was making some fundamental mistakes but basically on the right track.
First open the connection and connect as previously stated, making sure it is not ASYNC (this lead to some overlapped IO errors):
hInternet = InternetOpen("Test", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0/*INTERNET_FLAG_ASYNC*/);
hhttp = InternetConnect(hInternet, "192.168.111.222", INTERNET_DEFAULT_HTTP_PORT, "admin", "admin", INTERNET_SERVICE_HTTP, 0, 0);
I needed to create the request and then send it. I only needed to specify the page as the request will take in connection details.
hHttpRequest = HttpOpenRequest(hhttp, "GET", "home.html", NULL, NULL, lplpszAcceptTypes, INTERNET_FLAG_RELOAD | INTERNET_FLAG_PRAGMA_NOCACHE, 0);
HttpSendRequest(hHttpRequest, NULL, 0, NULL, 0);
Then use the HttpQueryInfo function to retrieve the status and convert back to integer. Make sure you are sending the handle from the Request not the Connect.
//These are defined earlier
DWORD statCharLen = 0;
char statChar[256]="";
statCharLen = sizeof(statChar);
HttpQueryInfo(hHttpRequest, HTTP_QUERY_STATUS_CODE, statChar, &statCharLen, NULL);
Finally shut down connection:
InternetCloseHandle(hInternet)
Thanks
Its is Simple following are the Steps:
1- Open Connection
2- Connect
3- Open request
4- Send request
5- Read file
6- Save file (as png or jpg)
7- Close handles
The code is as follow:
#include <iostream>
#include <string>
#include <Windows.h>
#include <wininet.h>
#pragma comment(lib, "wininet")
using namespace std;
void download(string domain,string url,string filepath)
{
//Step 1:
HINTERNET hIntSession = InternetOpenA("MyApp", INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
//Step 2:
HINTERNET hHttpSession = InternetConnectA(hIntSession, domain.c_str(), 80, 0, 0, INTERNET_SERVICE_HTTP, 0, NULL);
//Step 3:
HINTERNET hHttpRequest = HttpOpenRequestA( hHttpSession, "GET",url.c_str(),0, 0, 0, INTERNET_FLAG_RELOAD, 0);
TCHAR* szHeaders = L"";
CHAR szReq[1024] = "";
//Step 4:
if( !HttpSendRequest(hHttpRequest, szHeaders, wcslen(szHeaders), szReq, strlen(szReq))) {
DWORD dwErr = GetLastError();
cout<<"error "<<dwErr<<endl;
/// handle error
}
TCHAR szBuffer[1025];
DWORD dwRead=0;
FILE *f;
f=fopen(filepath.c_str(),"wb");
//Step 5 & 6:
while(InternetReadFile(hHttpRequest,szBuffer, 1024, &dwRead) && dwRead)
{
fwrite(szBuffer,sizeof(BYTE),1024,f);
dwRead=0;
}
fclose(f);
//Step 7:
InternetCloseHandle(hHttpRequest);
InternetCloseHandle(hHttpSession);
InternetCloseHandle(hIntSession);
}
int main()
{
download("www.stacktoheap.com","images/stackoverflow.png","C:\\Example\\example.png");
}
I'm trying to make this program connect to a website and submit form data in order to login, but I don't know what I'm doing wrong. I have heard of others like curl and Winsock but I chose the WinINet library. So just for the testing of this program I've been using the website Pastebin to post to. So far, I haven't seen any results from this. If this program succeeds in posting the form data it will give me the header to the location of the post on their site.
Am I writing the form data char* correctly? I have seen on other stackoverflow posts where they had a large amount of dashes before some number then the put their form data.
Do I need to add something to it make it simulate clicking the submit button?
Do I need to write out values for each elements on the form?
I have tried HttpAddRequestHeaders and that didn't help me.
Also, I get the ERROR_INSUFFICIENT_BUFFER error on HttpOpenRequest but it still returns a valid HINTERNET.
#include <Windows.h>
#include <WinInet.h>
#include <iostream>
#pragma comment( lib,"Wininet.lib")
using namespace std;
char* getheaders(HINTERNET hRequest){
DWORD dwInfoLevel=HTTP_QUERY_RAW_HEADERS_CRLF;
DWORD dwInfoBufferLength=10;
char* pInfoBuffer=(char*)malloc(dwInfoBufferLength+1);
while(!HttpQueryInfo(hRequest,dwInfoLevel,pInfoBuffer,&dwInfoBufferLength,NULL)){
if (GetLastError()==ERROR_INSUFFICIENT_BUFFER){
free(pInfoBuffer);
pInfoBuffer=(char*)malloc(dwInfoBufferLength+1);
}else{
fprintf(stderr,"HttpQueryInfo failed, error = %d (0x%x)\n",GetLastError(),GetLastError());
break;
}
}
pInfoBuffer[dwInfoBufferLength] = '\0';
return pInfoBuffer;
}
void readfile(HINTERNET hRequest,char** buffs,int size){
DWORD dwBytesAvailable;
DWORD dwBytesRead;
for(int i=0;i<size;i++){
if(!InternetQueryDataAvailable(hRequest,&dwBytesAvailable,0,0)) break;
buffs[i]=(char*)malloc(dwBytesAvailable+1);
bool bResult=InternetReadFile(hRequest,buffs[i],dwBytesAvailable,&dwBytesRead);
if(!bResult | dwBytesRead==0) break;
}
}
int main(int argc,char** argv){
char* hdrs="Content-Type: application/x-www-form-urlencoded";
char* frmdata="paste_code=test";
LPCSTR accept[2]={"*/*", NULL};
HINTERNET hSession = InternetOpen("http generic",INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
HINTERNET hConnect = InternetConnect(hSession, "www.pastebin.com",INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
HINTERNET hRequest = HttpOpenRequest(hConnect, "GET","/", NULL, NULL, accept, 0, 0);
//ERROR_INSUFFICIENT_BUFFER (122) with "accept".
bool send=HttpSendRequest(hRequest, hdrs, strlen(hdrs), NULL,NULL);
if(!send){
printf("HttpSendRequest failed, code=%d",GetLastError());
system("pause>nul");
return 0;
}
char* heads=getheaders(hRequest);
printf("%s\n\n\n\n",heads);
HINTERNET hRequest2 = HttpOpenRequest(hConnect, "POST","/", NULL, NULL, accept, 0, 0);
//ERROR_INSUFFICIENT_BUFFER (122) with "accept".
send=HttpSendRequest(hRequest2, hdrs, strlen(hdrs), frmdata,strlen(frmdata));
if(!send){
printf("HttpSendRequest failed, code=%d",GetLastError());
system("pause>nul");
return 0;
}
heads=getheaders(hRequest);
printf("%s\n\n\n\n",heads);
InternetCloseHandle(hRequest);
InternetCloseHandle(hRequest2);
InternetCloseHandle(hConnect);
InternetCloseHandle(hSession);
system("pause>nul");
return 0;
}
Your code is nearly correct, you must make sure of the following points:
char* hdrs="Content-Type: application/x-www-form-urlencoded";
you must make sure that your return object from POST message will be of type x-www-form-urlencoded or JSON . if it's JSON you
need to define char* hdrs="Content-Type: application/json\r\n";
Note: you must append \r\n to the hdrs.
try to call readFile method with buffer of size 10000 for example
and print buffer , it will print the output of the response to the
connection
In HINTERNET hRequest2 = HttpOpenRequest(hConnect, "POST","/", NULL, NULL, accept, 0, 0); instead of "/" you must call the path of
the requested API for example: .
In HINTERNET hRequest2 = HttpOpenRequest(hConnect, "POST", "/users/jsonlogin", NULL, NULL, accept, 0, 0);