HttpAddRequestHeaders Function

---

Adds one or more HTTP request headers to the HTTP request handle.

Syntax

BOOL HttpAddRequestHeaders(
    IN HINTERNET hConnect,
    IN LPCTSTR lpszHeaders,
    IN DWORD dwHeadersLength,
    IN DWORD dwModifiers
);

The actual syntax of this function varies between its ANSI and Unicode implementations. For more information, see Win32 Internet Functions Syntax.

Parameters

hConnect

HINTERNET handle returned by a call to the HttpOpenRequest function.

lpszHeaders

Address of a string variable containing the headers to append to the request. Each header must be terminated by a CR/LF (carriage return/line feed) pair.

dwHeadersLength

Unsigned long integer value that contains the length, in TCHAR, of lpszHeaders. If this parameter is -1L, the function assumes that lpszHeaders is zero-terminated (ASCIIZ), and the length is computed.

dwModifiers

Unsigned long integer value that contains the flags used to modify the semantics of this function. Can be a combination of the following values:

HTTP_ADDREQ_FLAG_ADD

Adds the header if it does not exist. Used with HTTP_ADDREQ_FLAG_REPLACE.

HTTP_ADDREQ_FLAG_ADD_IF_NEW

Adds the header only if it does not already exist; otherwise, an error is returned.

HTTP_ADDREQ_FLAG_COALESCE

Coalesces headers of the same name.

HTTP_ADDREQ_FLAG_COALESCE_WITH_COMMA

Coalesces headers of the same name. For example, adding "Accept: text/*" followed by "Accept: audio/*" with this flag results in the formation of the single header "Accept: text/*, audio/*". This causes the first header found to be coalesced. It is up to the calling application to ensure a cohesive scheme with respect to coalesced/separate headers.

HTTP_ADDREQ_FLAG_COALESCE_WITH_SEMICOLON

Coalesces headers of the same name using a semicolon.

HTTP_ADDREQ_FLAG_REPLACE

Replaces or removes a header. If the header value is empty and the header is found, it is removed. If not empty, the header value is replaced.

Return Value

Returns TRUE if successful, or FALSE otherwise. To get extended error information, call GetLastError.

Remarks

HttpAddRequestHeaders appends additional, free-format headers to the HTTP request handle and is intended for use by sophisticated clients that need detailed control over the exact request sent to the HTTP server.

Note that for basic HttpAddRequestHeaders, the application can pass in multiple headers in a single buffer. If the application is trying to remove or replace a header, only one header can be supplied in lpszHeaders.

Function Information

Windows NT	Use version 4.0. Implemented as ANSI and Unicode functions.
Windows	Use Windows 95 and later. Implemented as ANSI and Unicode functions.
Header	Wininet.h
Import library	Wininet.lib
Minimum availability	Internet Explorer 3.0 (ANSI only), 5 (ANSI and Unicode)

Windows CE

Windows CE	Use version 2.12 and later. Implemented as ANSI and Unicode functions.
Minimum availability	Internet Explorer 4.0

See Also

Microsoft Win32 Internet Functions Overview, HTTP Sessions, Microsoft Win32 Internet Functions Reference, HTTP Functions