I am making a simple POST request using WinInet to an apache web server. I encode the data using base 64. The problem is that, every + character gets replaced by space character.
Why is that and how can I make correct POST request.
hInternet = InternetOpen(NULL, INTERNETOPENTYPEPRECONFIG, NULL, NULL, 0);
if (hInternet)
{
hConnect = InternetConnect(hInternet, szDomain, INTERNETDEFAULTHTTPPORT, NULL, NULL, INTERNETSERVICEHTTP, 0, dwTmp);
if (hConnect)
{
hRequest = HttpOpenRequest(hConnect, szPost, szExfiltrationURL, NULL, NULL,(char *)accept, INTERNETFLAGNOCACHEWRITE | INTERNETFLAGNOCOOKIES | INTERNETFLAGNOUI | INTERNETFLAGRELOAD, 0);
if (hRequest)
{
HttpSendRequest(hRequest, headers, lstrlen(headers), buffer, buflen);
InternetCloseHandle(hRequest);
}
InternetCloseHandle(hConnect);
}
InternetCloseHandle(hInternet);
}
From W3
"Within the query string, the plus sign is reserved as shorthand
notation for a space:
Source: "http://www.w3.org/Addressing/URL/4_URI_Recommentations.html"
Related
This function creates a post request to an endpoint and receives a JSON response, the goal is to save the json data as a string.
I checked the Microsoft docs but I can't figure it out
void POST(std::string data, std::string endpoint )
{
static TCHAR hdrs[] = _T("Content-Type: application/json");
static LPCSTR accept[2]={"*/*", NULL};
// for clarity, error-checking has been removed
HINTERNET hSession = InternetOpen(DEFAULT_USERAGENT, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
HINTERNET hConnect = InternetConnect(hSession, MY_HOST, ALT_HTTP_PORT , NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
HINTERNET hRequest = HttpOpenRequest(hConnect, "POST", endpoint.c_str(), NULL, NULL, accept, 0, 1);
HttpSendRequest(hRequest, hdrs, strlen(hdrs), (PVOID)data.c_str() , data.length());
// close any valid internet-handles
}
I need to make a POST request to an API to get some XML data (http://freecite.library.brown.edu/welcome/api_instructions). This works fine with curl:
curl -H "Accept: application/xml" --data "citation=Udvarhelyi, I.S., Gatsonis, C.A., Epstein, A.M., Pashos, C.L., Newhouse, J.P. and McNeil, B.J. Acute Myocardial Infarction in the Medicare population: process of care and clinical outcomes. Journal of the American Medical Association, 1992; 18:2530-2536. " http://freecite.library.brown.edu:80/citations/create
So I am trying to do a similar thingy using Win32 SDK. This is my code:
void LoadData()
{
wil::unique_hinternet hInternet(InternetOpen(L"Dummy", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0));
wil::unique_hinternet hConnect(InternetConnect(hInternet.get(), L"http://freecite.library.brown.edu", 80, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0));
wil::unique_hinternet hRequest(HttpOpenRequest(hConnect.get(), L"POST", L"/citations/create", NULL, NULL, NULL, NULL, NULL));
wstring data = L"citation=Udvarhelyi, I.S., Gatsonis, C.A., Epstein, A.M., Pashos, C.L., Newhouse, J.P. and McNeil, B.J. Acute Myocardial Infarction in the Medicare population: process of care and clinical outcomes. Journal of the American Medical Association, 1992; 18:2530-2536.";
PCWSTR szHeaders = L"Accept: application/xml";
HttpSendRequest(hRequest.get(), szHeaders, 0, (LPVOID)data.c_str(), static_cast<int>(data.length()));
DWORD availableBytes = 0;
InternetQueryDataAvailable(hRequest.get(), &availableBytes, 0, 0);
PBYTE outputBuffer = (PBYTE)HeapAlloc(GetProcessHeap(), 0, availableBytes);
PBYTE nextBytes = outputBuffer;
DWORD bytesUsed = 0; // number of used bytes.
while (availableBytes)
{
DWORD downloadedBytes;
InternetReadFile(hRequest.get(), nextBytes, availableBytes, &downloadedBytes);
bytesUsed = bytesUsed + downloadedBytes;
InternetQueryDataAvailable(hRequest.get(), &availableBytes, 0, 0);
if (availableBytes > 0)
{
// lazy buffer growth here. Only alloc for what we need. could be optimized if we end up with huge payloads (>10MB).
// otherwise, this is good enough.
outputBuffer = (PBYTE)HeapReAlloc(GetProcessHeap(), 0, outputBuffer, bytesUsed + availableBytes);
nextBytes = outputBuffer + bytesUsed; // careful, pointer might have moved! Update cursor.
}
}
// Convert outputed XML to wide char
int size_needed = MultiByteToWideChar(CP_UTF8, 0, (PCCH)outputBuffer, bytesUsed, NULL, 0);
std::wstring wstrTo(size_needed, 0);
MultiByteToWideChar(CP_UTF8, 0, (PCCH)outputBuffer, bytesUsed, &wstrTo[0], size_needed);
wstring res = wstrTo;
}
The problem is, before entering the for loop, even after the call to InternetQueryDataAvailable, availableBytes comes out to be 0. As a result, I finally end up getting a blank string as response, whereas I was expecting a XML response.
Can anyone point me what am I doing wrongly, and how to fix it?
InternetConnect expects server name or IP address, so don't include "http://" in the address. Change to:
InternetConnect(handle, L"freecite.library.brown.edu"...);
Use UTF-8 for data. Other parameters for WinAPI functions are correctly using UTF-16, they automatically make the necessary conversions.
Change the header:
std::wstring szHeaders = L"Content-Type: application/x-www-form-urlencoded\r\n";
accept should be sent through HttpOpenRequest
const wchar_t *accept[] = { L"text/xml", NULL };
HINTERNET hrequest = HttpOpenRequest(hconnect, L"POST", L"/citations/create",
NULL, NULL, accept, 0, 0);
Note, if you don't specify accept (use NULL in its place) then the result can be in plain html.
The example below should return XML.
Note, for simplicity I put optional as ANSI string, but it should be UTF8, then you convert it to UTF16 woptional and send it. result will be UTF8 string, it should be converted to UTF16 for Windows's display.
#include <iostream>
#include <string>
#include <Windows.h>
#include <WinINet.h>
#pragma comment(lib, "wininet.lib")//include WinINet library
int main()
{
std::string result;
std::wstring server = L"freecite.library.brown.edu";
std::wstring objectname = L"/citations/create"; //file in this case!
std::wstring header = L"Content-Type: application/x-www-form-urlencoded\r\n";
std::string optional = "citation=Udvarhelyi, I.S., Gatsonis, C.A., Epstein";
HINTERNET hsession = InternetOpen(L"appname",
INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
HINTERNET hconnect = InternetConnect(hsession, server.c_str(),
INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
const wchar_t* accept[] = { L"text/xml", NULL };
HINTERNET hrequest = HttpOpenRequest(hconnect, L"POST", objectname.c_str(),
NULL, NULL, accept, 0, 0);
if(HttpSendRequest(hrequest, header.c_str(), header.size(),
&optional[0], optional.size()))
{
DWORD blocksize = 4096;
DWORD received = 0;
std::string block(blocksize, 0);
while (InternetReadFile(hrequest, &block[0], blocksize, &received)
&& received)
{
block.resize(received);
result += block;
}
std::cout << result << std::endl;
}
if (hrequest) InternetCloseHandle(hrequest);
if (hconnect) InternetCloseHandle(hconnect);
if (hsession) InternetCloseHandle(hsession);
return 0;
}
I use WinHTTP to get text from URL http://www.google.com/complete/search?output=toolbar&hl=vi&q=hoazzztf. The reponse text must be: <toplevel/> but I get the reponse like this:
Any idea? Thank!
(Reponse text may contains UTF-8 character)
DWORD dwSize = 0;
DWORD dwDownloaded = 0;
LPSTR pszOutBuffer;
HINTERNET hSession = NULL;
HINTERNET hConnect = NULL;
HINTERNET hRequest = NULL;
BOOL bResults = FALSE;
hSession = WinHttpOpen(L"WinHTTP Example/1.0",
WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
WINHTTP_NO_PROXY_NAME,
WINHTTP_NO_PROXY_BYPASS, 0);
WinHttpSetTimeouts(hSession, 1000, 2000, 1000, 1000);
// Specify an HTTP server.
if (hSession)
hConnect = WinHttpConnect(hSession, L"www.google.com",
INTERNET_DEFAULT_HTTPS_PORT, 0);
// Create an HTTP request handle.
if (hConnect)
hRequest = WinHttpOpenRequest(hConnect, L"GET", L"/complete/search?output=toolbar&hl=vi&q=hoazzztf",
NULL, WINHTTP_NO_REFERER,
WINHTTP_DEFAULT_ACCEPT_TYPES,
WINHTTP_FLAG_SECURE);
// Send a request.
if (hRequest)
bResults = WinHttpSendRequest(hRequest,
WINHTTP_NO_ADDITIONAL_HEADERS,
0, WINHTTP_NO_REQUEST_DATA, 0,
0, 0);
if (bResults)
bResults = WinHttpReceiveResponse(hRequest, NULL);
if (!bResults)
{
SetWindowText(hWnd, L"ERR-4");
break;
}
if (bResults)
{
do
{
// Check for available data.
dwSize = 0;
if (!WinHttpQueryDataAvailable(hRequest, &dwSize))
{
break;
}
// No more available data.
if (!dwSize)
break;
// Allocate space for the buffer.
pszOutBuffer = new char[dwSize + 1];
if (!pszOutBuffer)
{
break;
}
// Read the Data.
ZeroMemory((LPVOID)pszOutBuffer, dwSize + 1);
if (!WinHttpReadData(hRequest, (LPVOID)pszOutBuffer,
dwSize, &dwDownloaded))
{
}
else
{
MessageBox(hWnd, (LPCWSTR)pszOutBuffer, L"", NULL);
}
// Free the memory allocated to the buffer.
delete[] pszOutBuffer;
// This condition should never be reached since WinHttpQueryDataAvailable
// reported that there are bits to read.
if (!dwDownloaded)
break;
} while (dwSize > 0);
}
// Report any errors.
// Close any open handles.
if (hRequest) WinHttpCloseHandle(hRequest);
if (hConnect) WinHttpCloseHandle(hConnect);
if (hSession) WinHttpCloseHandle(hSession);
WinHttpReadData reads raw data, but you forced it to be an array of 2-byte WCHAR's. I think google uses utf-8 encoding on their pages, so you need to convert it first.
Another problem in your code is that you don't set terminating 0:
...
else
{
pszOutBuffer[ dwDownloaded ] = 0;
MessageBox(hWnd, pszOutBuffer, "", NULL);
}
Then, checking value returned by new is senseless, because new throws an exception in case of failure.
I fixed:
MessageBox(hWnd, (LPCWSTR)pszOutBuffer, L"", NULL);
to:
int wchars_num = MultiByteToWideChar(CP_UTF8, 0, pszOutBuffer, -1, NULL, 0);
wchar_t* wstr = new wchar_t[wchars_num];
MultiByteToWideChar(CP_UTF8, 0, pszOutBuffer, -1, wstr, wchars_num);
I'm not programming at C++, but i'm asking for someone who does, so i'm sorry if my question is simple or stupid.
I need a simple example of using HttpOpenRequest/HttpSendRequest objects in order to send JSON data to some web service/site.
Thank you
Here is a very bare bones example to send a JSON string to http://hostname/path/scriptname. You will have to add proper error checking, status code checking, etc as needed:
HINTERNET hInternet = InternetOpen(_T("MyApp"), INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
HINTERNET hConnect = InternetConnect(hInternet, _T("hostname"), INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 0);
LPTSTR rgpszAcceptTypes[] = {_T("application/json"), NULL};
HINTERNET hRequest = HttpOpenRequest(hConnect, _T("POST"), _T("/path/scriptname"), NULL, NULL, rgpszAcceptTypes, 0, 0);
HttpAddRequestHeaders(hRequest, _T("Content-Type: application/json\r\n"), -1, HTTP_ADDREQ_FLAG_ADD);
char *JsonData = "..."; // your actual JSON data here
HttpSendRequest(hRequest, NULL, 0, JsonData, strlen(JsonData))
DWORD StatusCode = 0;
DWORD StatusCodeLen = sizeof(StatusCode);
HttpQueryInfo(hRequest, HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER, &StatusCode, &StatusCodeLen, NULL);
if (StatusCode == 200)
{
// use InternetQueryDataAvailable() and InternetReadFile()
// to read any response data as needed...
}
InternetCloseHandle(hRequest);
InternetCloseHandle(hConnect);
InternetCloseHandle(hInternet);
String* Adder::downloadUrl(String* url)
{
DWORD dwSize = 0;
LPVOID lpOutBuffer = NULL;
BOOL bResults = FALSE;
HINTERNET hSession = NULL,
hConnect = NULL,
hRequest = NULL;
// Use WinHttpOpen to obtain a session handle.
hSession = WinHttpOpen( L"A WinHTTP Example Program/1.0",
WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
WINHTTP_NO_PROXY_NAME,
WINHTTP_NO_PROXY_BYPASS, 0);
// Specify an HTTP server.
if (hSession)
hConnect = WinHttpConnect( hSession, L"www.google.com",
INTERNET_DEFAULT_HTTP_PORT, 0);
// Create an HTTP request handle.
if (hConnect)
hRequest = WinHttpOpenRequest( hConnect, L"GET", NULL,
NULL, WINHTTP_NO_REFERER,
WINHTTP_DEFAULT_ACCEPT_TYPES,
0);
// Send a request.
if (hRequest)
bResults = WinHttpSendRequest( hRequest,
WINHTTP_NO_ADDITIONAL_HEADERS,
0, WINHTTP_NO_REQUEST_DATA, 0,
0, 0);
// End the request.
if (bResults)
bResults = WinHttpReceiveResponse( hRequest, NULL);
// First, use WinHttpQueryHeaders to obtain the size of the buffer.
if (bResults)
{
WinHttpQueryHeaders( hRequest, WINHTTP_QUERY_RAW_HEADERS_CRLF,
WINHTTP_HEADER_NAME_BY_INDEX, NULL,
&dwSize, WINHTTP_NO_HEADER_INDEX);
// Allocate memory for the buffer.
if( GetLastError( ) == ERROR_INSUFFICIENT_BUFFER )
{
lpOutBuffer = new WCHAR[dwSize/sizeof(WCHAR)];
// Now, use WinHttpQueryHeaders to retrieve the header.
bResults = WinHttpQueryHeaders( hRequest,
WINHTTP_QUERY_RAW_HEADERS_CRLF,
WINHTTP_HEADER_NAME_BY_INDEX,
lpOutBuffer, &dwSize,
WINHTTP_NO_HEADER_INDEX);
}
}
// Print the header contents.
if (bResults)
printf("Header contents: \n%S",lpOutBuffer);
// Free the allocated memory.
delete [] lpOutBuffer;
// 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);
String* retOne;
return retOne;
}
I want to get response as string i am using dll in C#, dont know vc++ at all, please suggest a way.
String* retOne //how to get response;
return retOne;
UPDATE
// Convert a wide Unicode string to an UTF8 string
std::string utf8_encode(const std::wstring &wstr)
{
int size_needed = WideCharToMultiByte(CP_UTF8, 0, &wstr[0], (int)wstr.size(), NULL, 0, NULL, NULL);
std::string strTo( size_needed, 0 );
WideCharToMultiByte (CP_UTF8, 0, &wstr[0], (int)wstr.size(), &strTo[0], size_needed, NULL, NULL);
return strTo;
}
String* retOne = utf8_encode(lpOutBuffer);
Gives error: 'utf8_encode' : cannot convert parameter 1 from 'LPVOID' to 'const std::wstring
Please don't post comments suggesting use of .net libraries.
Looks like you need the WideCharToMultiByte function
Whats hard in this process is to understand the function WideCharToMultiByte.
Basically what you need to do in order to get the whole string (and avoid garbage as a result of not having a null terminating string) is first use:
int size_needed = WideCharToMultiByte(CP_UTF8, 0, (LPCWCH)lpOutBuffer, -1, NULL, 0, NULL, NULL);
char *stringMe = new char[size_needed + 1];
While size_needed will be the required buffer size for lpMultiByteStr in the WideCharToMultiByte function.
Afterwards you just need to use that function again, since now you have the complete size:
WideCharToMultiByte(CP_UTF8, 0, (LPCWCH)lpOutBuffer, -1, stringMe, size_needed, NULL, NULL);
stringMe[size_needed + 1] = NULL;
Now you can also convert it to String:
std::string serverOutput(stringMe);
Try this:
String* retOne = utf8_encode(std::wstring(lpOutBuffer));
or
String* retOne = utf8_encode(std::wstring((WCHAR*)lpOutBuffer));