IWinHttpRequest::Open method
The Open method opens an HTTP connection to an HTTP resource.
Syntax
HRESULT Open(
[in] BSTR Method,
[in] BSTR Url,
[in, optional] VARIANT Async
);
Parameters
-
Method [in]
-
Specifies the HTTP verb used for the Open method, such as "GET" or "PUT". Always use uppercase as some servers ignore lowercase HTTP verbs.
-
Url [in]
-
Specifies the name of the resource. This must be an absolute URL.
-
Async [in, optional]
-
Indicates whether to open in asynchronous mode.
Value Meaning - VARIANT_FALSE
Opens the HTTP connection in synchronous mode. A call to Send does not return until WinHTTP has completely received the response. - VARIANT_TRUE
Opens the HTTP connection in asynchronous mode.
Return value
The return value is S_OK on success or an error value otherwise.
Remarks
This method opens a connection to the resource identified in Url using the HTTP verb given in Method.
Note
For Windows XP and Windows 2000, see the Run-Time Requirements section of the WinHTTP Start Page.
Examples
The following example shows how to open an HTTP connection, send an HTTP request, and read the response text.
#include <windows.h>
#include <stdio.h>
#include <objbase.h>
#include "httprequest.h"
#pragma comment(lib, "ole32.lib")
#pragma comment(lib, "oleaut32.lib")
// IID for IWinHttpRequest.
const IID IID_IWinHttpRequest =
{
0x06f29373,
0x5c5a,
0x4b54,
{0xb0, 0x25, 0x6e, 0xf1, 0xbf, 0x8a, 0xbf, 0x0e}
};
int main()
{
// Variable for return value
HRESULT hr;
// Initialize COM
hr = CoInitialize( NULL );
IWinHttpRequest * pIWinHttpRequest = NULL;
BSTR bstrResponse = NULL;
VARIANT varFalse;
VARIANT varEmpty;
CLSID clsid;
VariantInit(&varFalse);
V_VT(&varFalse) = VT_BOOL;
V_BOOL(&varFalse) = VARIANT_FALSE;
VariantInit(&varEmpty);
V_VT(&varEmpty) = VT_ERROR;
hr = CLSIDFromProgID(L"WinHttp.WinHttpRequest.5.1",
&clsid);
if (SUCCEEDED(hr))
{
hr = CoCreateInstance(clsid,
NULL,
CLSCTX_INPROC_SERVER,
IID_IWinHttpRequest,
(void **)&pIWinHttpRequest);
}
if (SUCCEEDED(hr))
{
// Open WinHttpRequest.
BSTR bstrMethod = SysAllocString(L"GET");
BSTR bstrUrl = SysAllocString(L"https://microsoft.com");
hr = pIWinHttpRequest->Open(bstrMethod,
bstrUrl,
varFalse);
SysFreeString(bstrMethod);
SysFreeString(bstrUrl);
}
if (SUCCEEDED(hr))
{
// Send Request.
hr = pIWinHttpRequest->Send(varEmpty);
}
if (SUCCEEDED(hr))
{
// Get Response text.
hr = pIWinHttpRequest->get_ResponseText(&bstrResponse);
}
if (SUCCEEDED(hr))
{
// Print the response to a console.
wprintf(L"%.256s",bstrResponse);
}
// Release memory.
if (pIWinHttpRequest)
pIWinHttpRequest->Release();
if (bstrResponse)
SysFreeString(bstrResponse);
CoUninitialize();
return 0;
}
The following scripting example shows how to open an HTTP connection, send an HTTP request, and read the response text.
// Instantiate a WinHttpRequest object.
var WinHttpReq = new ActiveXObject("WinHttp.WinHttpRequest.5.1");
// Initialize an HTTP request.
WinHttpReq.Open("GET", "https://www.microsoft.com", false);
// Send the HTTP request.
WinHttpReq.Send();
// Display the response text.
WScript.Echo( WinHttpReq.ResponseText);
Requirements
Requirement | Value |
---|---|
Minimum supported client |
Windows XP, Windows 2000 Professional with SP3 [desktop apps only] |
Minimum supported server |
Windows Server 2003, Windows 2000 Server with SP3 [desktop apps only] |
Redistributable |
WinHTTP 5.0 and Internet Explorer 5.01 or later on Windows XP and Windows 2000. |
IDL |
|
Library |
|
DLL |
|