NAME
khttp_head
—
emit one HTTP header for
kcgi
LIBRARY
library “libkcgi”
SYNOPSIS
#include
<sys/types.h>
#include <stdarg.h>
#include <stdint.h>
#include <kcgi.h>
enum kcgi_err
khttp_head
(struct kreq *req,
const char *key, const char
*fmt, ...);
extern const char *const kresps[KRESP__MAX];
DESCRIPTION
The
khttp_head
()
function takes a kcgi(3)
context req that was previously initialised by
khttp_parse(3) and
emits one HTTP header with the given HTTP response
key. The fmt string and variable
arguments, which follow printf(3) syntax, form the corresponding value in the HTTP response.
This function may only be invoked prior to
khttp_body(3);
otherwise, its behaviour is undefined.
The kresps global array, indexed with the
KRESP_*
symbolic constants defined in
<kcgi.h>
, provides standard
HTTP key names. Use it for the key argument to avoid
typos.
See khttp_body(3) for a discussion on the "Content-Encoding" header: do not specify this header before doing so!
RETURN VALUES
The khttp_head
() function returns an
enum kcgi_err indicating the error state.
KCGI_OK
- Success (not an error).
KCGI_ENOMEM
- Internal memory allocation failure.
KCGI_SYSTEM
- Internal system error writing to the output stream.
KCGI_HUP
- The output connection has been terminated. For FastCGI connections, the current connection should be released with khttp_free(3) and parse loop reentered.
EXAMPLES
To emit a session cookie (one-year expiration date) with key ckey and value cval for the global path, one may invoke the following. Assume that r is a pointer to a struct kreq successfully initialised by khttp_parse(3).
const char *ckey = "foo", *cval = "bar"; char buf[64]; khttp_epoch2str(time(NULL) + 31536000, buf, 64); khttp_head(r, kresps[KRESP_SET_COOKIE], "%s=%s; path=/; expires=%s", ckey, cval, buf);
SEE ALSO
STANDARDS
RFC 2616, section 14: “Header Field Definitions”.
The example references RFC 6265, section 4.1: “Set-Cookie”.
AUTHORS
The khttp_head
() function was written by
Kristaps Dzonsons
<kristaps@bsd.lv>.