This function opens an HTTP request handle.
At a Glance
| Header file: | Wininet.h |
| Windows CE versions: | 2.0 and later |
Syntax
HINTERNET WINAPI HttpOpenRequest(
HINTERNET hHttpSession, LPCTSTR lpszVerb, LPCTSTR lpszObjectName, LPCTSTR lpszVersion, LPCTSTR lpszReferrer,
LPCTSTR * lplpszAcceptTypes, DWORD dwFlags, DWORD dwContext);
Parameters
hHttpSession
[in] Handle to an HTTP session returned by InternetConnect.
lpszVerb
[in] Long pointer to a null-terminated string that contains the verb to use in the request. If this parameter is NULL, the function uses "GET" as the verb.
lpszObjectName
[in] Long pointer to a null-terminated string that contains the name of the target object of the specified verb. This is generally a file name, an executable module, or a search specifier.
lpszVersion
[in] Long pointer to a null-terminated string that contains the HTTP version. If this parameter is NULL, the function uses "HTTP/1.0" as the version.
lpszReferer
[in] Long pointer to a null-terminated string that specifies the address (URL) of the document from which the URL in the request (lpszObjectName) was obtained. If this parameter is NULL, no "referrer" is specified.
lplpszAcceptTypes
[in] Long pointer to a null-terminated array of string pointers indicating content types accepted by the client. If this parameter is NULL, no types are accepted by the client. Servers interpret a lack of accept types to indicate that the client accepts only documents of type "text/*" (that is, only text documents, and not pictures or other binary files).
dwFlags
[in] Specifies a bitmask of Internet flags. Can be any of the following values:
| Value | Description |
| INTERNET_FLAG_CACHE_IF_NET_FAIL | Return the resource from the cache if the network request for the resource fails due to an ERROR_INTERNET_CONNECTION_RESET or ERROR_INTERNET_CANNOT_CONNECT. |
| INTERNET_FLAG_DONT_CACHE | Not supported. Data is never cached. |
| INTERNET_FLAG_HYPERLINK | Forces a reload if there was no Expires time and no Last-Modified time returned from the server when determining whether to reload the item from the network. |
| INTERNET_FLAG_IGNORE_CERT_CN_INVALID | Disables Win32 Internet function checking of SSL/PCT-based certificates that are returned from the server against the host name given in the request. Win32 Internet functions use a simple check against certificates by comparing for matching host names and simple wildcarding rules. |
| INTERNET_FLAG_IGNORE_CERT_DATE_INVALID | Disables Win32 Internet function checking of SSL/PCT-based certificates for proper validity dates. |
| INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTP | Disables the ability of the Win32 Internet functions to detect this special type of redirect. When this flag is used, Win32 Internet functions transparently allow redirects from HTTPS to HTTP URLs. |
| INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTPS | Disables the ability of the Win32 Internet functions to detect this special type of redirect. When this flag is used, Win32 Internet functions transparently allow redirects from HTTP to HTTPS URLs. |
| INTERNET_FLAG_KEEP_CONNECTION | Uses keep-alive semantics, if available, for the connection. This flag is required for Microsoft Network (MSN), NT LAN Manager (NTLM), and other types of authentication. |
| INTERNET_FLAG_MAKE_PERSISTENT | Not supported. |
| INTERNET_FLAG_MUST_CACHE_REQUEST | Causes a temporary file to be created if the file cannot be cached. Identical to the preferred value INTERNET_FLAG_NEED_FILE. |
| INTERNET_FLAG_NEED_FILE | Causes a temporary file to be created if the file cannot be cached. |
| INTERNET_FLAG_NO_AUTH | Does not attempt authentication automatically. |
| INTERNET_FLAG_NO_AUTO_REDIRECT | Does not automatically handle redirection in HttpSendRequest. |
| INTERNET_FLAG_NO_CACHE_WRITE | Does not add the returned entity to the cache. |
| INTERNET_FLAG_NO_COOKIES | Does not automatically add cookie headers to requests, and does not automatically add returned cookies to the cookie database. |
| INTERNET_FLAG_NO_UI | Disables the cookie dialog box. |
| INTERNET_FLAG_PRAGMA_NOCACHE | Forces the request to be resolved by the origin server, even if a cached copy exists on the proxy. |
| INTERNET_FLAG_READ_PREFETCH | This flag is currently disabled. |
| INTERNET_FLAG_RELOAD | Not supported. Data is always from the wire and caching is not supported. |
| INTERNET_FLAG_RESYNCHRONIZE | Reloads HTTP resources if the resource has been modified since the last time it was downloaded. |
| INTERNET_FLAG_SECURE | Uses SSL/PCT transaction semantics. |
dwContext
[in] Specifies the application-defined value that associates this operation with any application data.
Return Values
A valid, non-NULL HTTP request handle indicates success. NULL indicates failure. To get extended error information, call GetLastError.
Remarks
HttpOpenRequest creates a new HTTP request handle and stores the specified parameters in that handle. An HTTP request handle holds a request to be sent to an HTTP server and contains all RFC822/MIME/HTTP headers to be sent as part of the request.
Use the InternetCloseHandle function to close the handle returned by HttpOpenRequest. InternetCloseHandle cancels all outstanding I/O on the handle.
The lpszReferer parameter to InternetOpen is used as the referrer for the HTTP request.
The dwContext parameter allows for progress status callbacks to the application, but all requests will be handled synchronously.
When establishing a Secure Sockets Layer (SSL) or Private Communications Technology, HttpOpenRequest uses the INTERNET_FLAG_SECURE option in addition to all other options.
The following dwFlags values can be used in HttpOpenRequest to ignore invalid certificate errors:
INTERNET_FLAG_IGNORE_CERT_CN_INVALID
Ignores errors caused when the certificate host name of the server does not match the host name in the request.
INTERNET_FLAG_IGNORE_CERT_DATE_INVALID
Ignores errors caused by an expired server certificate.
See Also