IWinHttpRequest::GetResponseHeader method

Článek
01/07/2021

The GetResponseHeader method retrieves the HTTP response headers.

Syntax

HRESULT GetResponseHeader(
  [in]          BSTR Header,
  [out, retval] BSTR *Value
);

Parameters

Header [in]: Specifies the case-insensitive header name.
Value [out, retval]: Receives the resulting header information.

Return value

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

Remarks

This method returns the value of the response header named in Header. Be aware that automation clients, such as script, get the header data as the return value of the function call, not through a function parameter. Invoke this method only after the Send method has been called.

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 get the date header from the response. This example must be run from a command prompt.

#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.
        BSTR bstrName = SysAllocString(L"Date");
        hr = pIWinHttpRequest->GetResponseHeader(bstrName,
                                             &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 open an HTTP connection, send an HTTP request, and get the date header from the response.

// 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 date header.
WScript.Echo( WinHttpReq.GetResponseHeader("Date"));

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

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