IWinHttpRequest::SetTimeouts method

Article
03/10/2021

The SetTimeouts method specifies the individual time-out components of a send/receive operation, in milliseconds.

Syntax

HRESULT SetTimeouts(
  [in] long ResolveTimeout,
  [in] long ConnectTimeout,
  [in] long SendTimeout,
  [in] long ReceiveTimeout
);

Parameters

ResolveTimeout [in]: Time-out value applied when resolving a host name (such as www.microsoft.com) to an IP address (such as 192.168.131.199), in milliseconds. The default value is zero, meaning no time-out (infinite). If DNS timeout is specified using NAME_RESOLUTION_TIMEOUT, there is an overhead of one thread per request.
ConnectTimeout [in]: Time-out value applied when establishing a communication socket with the target server, in milliseconds. The default value is 60,000 (60 seconds).
SendTimeout [in]: Time-out value applied when sending an individual packet of request data on the communication socket to the target server, in milliseconds. A large request sent to an HTTP server are normally be broken up into multiple packets; the send time-out applies to sending each packet individually. The default value is 30,000 (30 seconds).
ReceiveTimeout [in]: Time-out value applied when receiving a packet of response data from the target server, in milliseconds. Large responses are be broken up into multiple packets; the receive time-out applies to fetching each packet of data off the socket. The default value is 30,000 (30 seconds).

Return value

The return value is S_OK on success or an error value otherwise.

Remarks

All parameters are required. A value of 0 or -1 sets a time-out to wait infinitely. A value greater than 0 sets the time-out value in milliseconds. For example, 30,000 would set the time-out to 30 seconds. All negative values other than -1 cause this method to fail.

Time-out values are applied at the Winsock layer.

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 set all WinHTTP time-outs to 30 seconds, 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))
    {    // Set Time-outs.
        hr = pIWinHttpRequest->SetTimeouts(30000, 30000,
                                           30000, 30000);
    }
    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->GetAllResponseHeaders(&bstrResponse);
    }
    if (SUCCEEDED(hr))
    {    // Print response to 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 set all WinHTTP time-outs to 30 seconds, open an HTTP connection, and send an HTTP request.

// Instantiate a WinHttpRequest object.
var WinHttpReq = new ActiveXObject("WinHttp.WinHttpRequest.5.1");

// Set time-outs. If time-outs are set, they must 
// be set before open.
WinHttpReq.SetTimeouts(30000, 30000, 30000, 30000);

// Initialize an HTTP request.  
WinHttpReq.Open("GET", "https://www.microsoft.com", false);

// Send the HTTP request.
WinHttpReq.Send();

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	HttpRequest.idl
Library	Winhttp.lib
DLL	Winhttp.dll