WinHttpOpenRequest function (winhttp.h)

The WinHttpOpenRequest function creates an HTTP request handle.

Syntax

WINHTTPAPI HINTERNET WinHttpOpenRequest(
  [in] HINTERNET hConnect,
  [in] LPCWSTR   pwszVerb,
  [in] LPCWSTR   pwszObjectName,
  [in] LPCWSTR   pwszVersion,
  [in] LPCWSTR   pwszReferrer,
  [in] LPCWSTR   *ppwszAcceptTypes,
  [in] DWORD     dwFlags
);

Parameters

[in] hConnect

HINTERNET connection handle to an HTTP session returned by WinHttpConnect.

[in] pwszVerb

Pointer to a string that contains the HTTP verb to use in the request. If this parameter is NULL, the function uses GET as the HTTP verb. Note  This string should be all uppercase. Many servers treat HTTP verbs as case-sensitive, and the Internet Engineering Task Force (IETF) Requests for Comments (RFCs) spell these verbs using uppercase characters only.

[in] pwszObjectName

Pointer to a string that contains the name of the target resource of the specified HTTP verb. This is generally a file name, an executable module, or a search specifier.

[in] pwszVersion

Pointer to a string that contains the HTTP version. If this parameter is NULL, the function uses HTTP/1.1.

[in] pwszReferrer

Pointer to a string that specifies the URL of the document from which the URL in the request pwszObjectName was obtained. If this parameter is set to WINHTTP_NO_REFERER, no referring document is specified.

[in] ppwszAcceptTypes

Pointer to a null-terminated array of string pointers that specifies media types accepted by the client. If this parameter is set to WINHTTP_DEFAULT_ACCEPT_TYPES, no types are accepted by the client. Typically, servers handle a lack of accepted types as indication that the client accepts only documents of type "text/*"; that is, only text documents—no pictures or other binary files. For a list of valid media types, see Media Types defined by IANA at http://www.iana.org/assignments/media-types/.

[in] dwFlags

Unsigned long integer value that contains the Internet flag values. This can be one or more of the following values:

Return value

Returns a valid HTTP request handle if successful, or NULL if not. For extended error information, call GetLastError. Among the error codes returned are the following.

Remarks

The return value indicates success or failure. To get extended error information, call GetLastError.

The WinHttpOpenRequest function creates a new HTTP request handle and stores the specified parameters in that handle. An HTTP request handle holds a request to send to an HTTP server and contains all RFC822/MIME/HTTP headers to be sent as part of the request.

If pwszVerb is set to "HEAD", the Content-Length header is ignored.

If a status callback function has been installed with WinHttpSetStatusCallback, then a WINHTTP_CALLBACK_STATUS_HANDLE_CREATED notification indicates that WinHttpOpenRequest has created a request handle.

After the calling application finishes using the HINTERNET handle returned by WinHttpOpenRequest, it must be closed using the WinHttpCloseHandle function.

Examples

This example shows how to obtain an HINTERNET handle, open an HTTP session, create a request header, and send that header to the server.

    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.wingtiptoys.com",
                                   INTERNET_DEFAULT_HTTP_PORT, 0);

    // Create an HTTP Request handle.
    if (hConnect)
        hRequest = WinHttpOpenRequest( hConnect, L"PUT", 
                                       L"/writetst.txt", 
                                       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);

    // PLACE ADDITIONAL CODE HERE.

    // 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);

Requirements

See also

About Microsoft Windows HTTP Services (WinHTTP)

WinHTTP Versions

WinHttpConnect

WinHttpOpen