Expires Header [SIP Headers]

The Expires header field gives the date and time after which the message content expires. More...

Data Structures
struct	sip_expires_s
	Structure for Expires header. More...
Defines
#define	sip_expires(sip)
	Access a SIP Expires header structure sip_expires_t from sip_t.
#define	SIP_EXPIRES_INIT()
	Initializer for structure sip_expires_t.
#define	SIPTAG_EXPIRES(x)
	Tag list item for pointer to a Expires header structure sip_expires_t.
#define	SIPTAG_EXPIRES_REF(x)
	Tag list item for reference to a Expires header pointer.
#define	SIPTAG_EXPIRES_STR(s)
	Tag list item for string with Expires header value.
#define	SIPTAG_EXPIRES_STR_REF(x)
	Tag list item for reference to a Expires header string.
Typedefs
typedef struct sip_expires_s	sip_expires_t
	The structure sip_expires_t contains representation of SIP Expires header.
Functions
issize_t	sip_expires_d (su_home_t *, msg_header_t *, char *s, isize_t slen)
	Parse a SIP Expires header.
issize_t	sip_expires_e (char b[], isize_t bsiz, msg_header_t const *h, int flags)
	Print a SIP Expires header.
sip_expires_t *	sip_expires_init (sip_expires_t x[1])
	Initialize a structure sip_expires_t.
int	sip_is_expires (sip_header_t const *header)
	Test if header object is instance of sip_expires_t.
sip_expires_t *	sip_expires_dup (su_home_t *home, sip_expires_t const *hdr))
	Duplicate a list of Expires header header structures sip_expires_t.
sip_expires_t *	sip_expires_copy (su_home_t *home, sip_expires_t const *hdr))
	Copy a list of Expires header header structures sip_expires_t.
sip_expires_t *	sip_expires_make (su_home_t *home, char const *s))
	Make a Expires header structure sip_expires_t.
sip_expires_t *	sip_expires_format (su_home_t *home, char const *fmt,...)))
	Make a Expires header from formatting result.
sip_expires_t *	sip_expires_create (su_home_t *home, sip_time_t delta)
	Create an Expires header object.
sip_time_t	sip_contact_expires (sip_contact_t const *m, sip_expires_t const *ex, sip_date_t const *date, sip_time_t def, sip_time_t now)
	Calculate the expiration time for a SIP Contact.
Variables
msg_hclass_t	sip_expires_class []
	Header class for Expires header.
tag_typedef_t	siptag_expires
	Tag for Expires header object.
tag_typedef_t	siptag_expires_str
	Tag for string with Expires header value.

---

Detailed Description

The Expires header field gives the date and time after which the message content expires.

Its syntax is defined in RFC 3261 as follows:

    Expires     =  "Expires" HCOLON delta-seconds

Note that the first SIP revision (RFC 2543) also allowed absolute time in Expires.

The parsed Expires header is stored in sip_expires_t structure.

---

Define Documentation

#define SIP_EXPIRES_INIT

(

)

Initializer for structure sip_expires_t.

A static sip_expires_t structure for Expires header must be initialized with the SIP_EXPIRES_INIT() macro. For instance,

  sip_expires_t sip_expires = SIP_EXPIRES_INIT;

#define SIPTAG_EXPIRES

(

x

)

Tag list item for pointer to a Expires header structure sip_expires_t.

The SIPTAG_EXPIRES() macro is used to include a tag item with a pointer to a sip_expires_t structure in a tag list.

Parameters:

x

pointer to a sip_expires_t structure, or NULL.

The corresponding tag taking reference parameter is SIPTAG_EXPIRES_REF().

#define SIPTAG_EXPIRES_STR

(

s

)

Tag list item for string with Expires header value.

The SIPTAG_EXPIRES_STR() macro is used to include a tag item with a string containing value of a sip_expires_t header in a tag list.

Parameters:

s

pointer to a string containing Expires header value, or NULL.

The string in SIPTAG_EXPIRES_STR() can be converted to a sip_expires_t header structure by giving the string s has second argument to function sip_expires_make().

The corresponding tag taking reference parameter is SIPTAG_EXPIRES_STR_REF().

---

Typedef Documentation

typedef struct sip_expires_s sip_expires_t

The structure sip_expires_t contains representation of SIP Expires header.

The sip_expires_t is defined as follows:

 typedef struct sip_expires_s {
   sip_common_t        ex_common[1];  // Common fragment info
   sip_error_t        *ex_next;       // Link to next (dummy)
   sip_time_t          ex_date;       // Seconds since Jan 1, 1900
   sip_time_t          ex_delta;      // ...or delta seconds
 } sip_expires_t;

---

Function Documentation

sip_time_t sip_contact_expires	(	sip_contact_t const *	m,
		sip_expires_t const *	ex,
		sip_date_t const *	date,
		sip_time_t	def,
		sip_time_t	now
	)

Calculate the expiration time for a SIP Contact.

Calculate expiration time of a Contact header.

Parameters:

	m	Contact header
	ex	Expires header
	date	Date header
	def	default expiration time
	now	current time.

Note:

If m is NULL, the function calculates the expiration time based on the Expires and Date headers.

If now is 0, the function gets the current time using sip_now().

Returns:

The expiration time in seconds.

sip_expires_t * sip_expires_copy	(	su_home_t *	home,
		sip_expires_t const *	hdr
	)			[inline]

Copy a list of Expires header header structures sip_expires_t.

The function sip_expires_copy() copies a header structure hdr. If the header structure hdr contains a reference (hdr->h_next) to a list of headers, all the headers in that list are copied, too. The function uses given memory home to allocate all the memory areas used to copy the list of header structure hdr.

Parameters:

	home	memory home used to allocate new structure
	hdr	pointer to the header structure to be copied

When copying, only the header structure and parameter lists attached to it are duplicated. The new header structure retains all the references to the strings within the old hdr header, including the encoding of the old header, if present.

Example

   expires = sip_expires_copy(home, sip->sip_expires);

Returns:

A pointer to newly copied header structure, or NULL upon an error.

sip_expires_t* sip_expires_create	(	su_home_t *	home,
		sip_time_t	delta
	)

Create an Expires header object.

Create an Expires header object with the expiration time delta.

Parameters:

	home	memory home used to allocate sip_expires_t structure
	delta	relative expiration time in seconds

Returns:

A pointer to newly created Expires header object when successful or NULL upon an error.

sip_expires_t * sip_expires_dup	(	su_home_t *	home,
		sip_expires_t const *	hdr
	)			[inline]

Duplicate a list of Expires header header structures sip_expires_t.

Duplicate a header structure hdr. If the header structure hdr contains a reference (hdr->x_next) to a list of headers, all the headers in the list are duplicated, too.

Parameters:

	home	memory home used to allocate new structure
	hdr	header structure to be duplicated

When duplicating, all parameter lists and non-constant strings attached to the header are copied, too. The function uses given memory home to allocate all the memory areas used to copy the header.

Example

   expires = sip_expires_dup(home, sip->sip_expires);

Returns:

A pointer to the newly duplicated sip_expires_t header structure, or NULL upon an error.

sip_expires_t * sip_expires_format	(	su_home_t *	home,
		char const *	fmt,
			...
	)			[inline]

Make a Expires header from formatting result.

Make a new sip_expires_t object using formatting result as its value. The function first prints the arguments according to the format fmt specified. Then it allocates a new header structure, and parses the formatting result to the structure sip_expires_t.

Parameters:

	home	memory home used to allocate new header structure.
	fmt	string used as a printf()-style format
	...	argument list for format

Returns:

A pointer to newly makes header structure, or NULL upon an error.

sip_expires_t* sip_expires_init

(

sip_expires_t

x[1]

)

[inline]

Initialize a structure sip_expires_t.

An sip_expires_t structure for Expires header can be initialized with the sip_expires_init() function/macro. For instance,

  sip_expires_t sip_expires;

  sip_expires_init(&sip_expires);

sip_expires_t * sip_expires_make	(	su_home_t *	home,
		char const *	s
	)			[inline]

Make a Expires header structure sip_expires_t.

The function sip_expires_make() makes a new sip_expires_t header structure. It allocates a new header structure, and decodes the string s as the value of the structure.

Parameters:

	home	memory home used to allocate new header structure.
	s	string to be decoded as value of the new header structure

Returns:

A pointer to newly maked sip_expires_t header structure, or NULL upon an error.

int sip_is_expires

(

sip_header_t const *

header

)

[inline]

Test if header object is instance of sip_expires_t.

Check if the header class is an instance of Expires header object and return true (nonzero), otherwise return false (zero).

Parameters:

header

pointer to the header structure to be tested

Return values:

	1	(true) if the header is an instance of header expires
	0	(false) otherwise

---

Variable Documentation

msg_hclass_t sip_expires_class[]

Header class for Expires header.

The header class sip_expires_class defines how a SIP Expires header is parsed and printed. It also contains methods used by SIP parser and other functions to manipulate the sip_expires_t header structure.