Miscellaneous APIs

Functions
LWS_VISIBLE LWS_EXTERN int	lws_snprintf (char *str, size_t size, const char *format,...) LWS_FORMAT(3)
LWS_VISIBLE LWS_EXTERN int	lws_get_random (struct lws_context *context, void *buf, int len)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_daemonize (const char *_lock_path)
LWS_VISIBLE LWS_EXTERN const char *LWS_WARN_UNUSED_RESULT	lws_get_library_version (void)
LWS_VISIBLE LWS_EXTERN void *	lws_wsi_user (struct lws *wsi)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_parse_uri (char *p, const char **prot, const char **ads, int *port, const char **path)
LWS_VISIBLE LWS_EXTERN unsigned long	lws_now_secs (void)
LWS_VISIBLE LWS_EXTERN struct lws_context *LWS_WARN_UNUSED_RESULT	lws_get_context (const struct lws *wsi)
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT	lws_get_count_threads (struct lws_context *context)
LWS_VISIBLE LWS_EXTERN struct lws *LWS_WARN_UNUSED_RESULT	lws_get_parent (const struct lws *wsi)
LWS_VISIBLE LWS_EXTERN struct lws *LWS_WARN_UNUSED_RESULT	lws_get_child (const struct lws *wsi)
LWS_VISIBLE LWS_EXTERN int	lws_read (struct lws *wsi, unsigned char *buf, size_t len)
LWS_VISIBLE LWS_EXTERN void	lws_set_allocator (void *(*realloc)(void *ptr, size_t size))

Detailed Description

Miscellaneous APIs

Various APIs outside of other categories

Function Documentation

lws_daemonize()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_daemonize

(

const char *

_lock_path

)

#include <lib/libwebsockets.h>

lws_daemonize(): fill a buffer with platform random data

Parameters

_lock_path

the filepath to write the lock file

Spawn lws as a background process, taking care of various things

lws_get_child()

LWS_VISIBLE LWS_EXTERN struct lws* LWS_WARN_UNUSED_RESULT lws_get_child

(

const struct lws *

wsi

)

#include <lib/libwebsockets.h>

lws_get_child() - get child wsi or NULL

Parameters

wsi	lws connection

Allows you to find a related wsi from the parent wsi.

lws_get_context()

LWS_VISIBLE LWS_EXTERN struct lws_context* LWS_WARN_UNUSED_RESULT lws_get_context

(

const struct lws *

wsi

)

#include <lib/libwebsockets.h>

lws_get_context - Allow geting lws_context from a Websocket connection instance

With this function, users can access context in the callback function. Otherwise users may have to declare context as a global variable.

Parameters

wsi	Websocket connection instance

lws_get_count_threads()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_get_count_threads

(

struct lws_context *

context

)

#include <lib/libwebsockets.h>

lws_get_count_threads(): how many service threads the context uses

Parameters

context

the lws context

By default this is always 1, if you asked for more than lws can handle it will clip the number of threads. So you can use this to find out how many threads are actually in use.

lws_get_library_version()

LWS_VISIBLE LWS_EXTERN const char* LWS_WARN_UNUSED_RESULT lws_get_library_version

(

void

)

#include <lib/libwebsockets.h>

lws_get_library_version(): return string describing the version of lws

On unix, also includes the git describe

lws_get_parent()

LWS_VISIBLE LWS_EXTERN struct lws* LWS_WARN_UNUSED_RESULT lws_get_parent

(

const struct lws *

wsi

)

#include <lib/libwebsockets.h>

lws_get_parent() - get parent wsi or NULL

Parameters

wsi	lws connection

Specialized wsi like cgi stdin/out/err are associated to a parent wsi, this allows you to get their parent.

lws_get_random()

LWS_VISIBLE LWS_EXTERN int lws_get_random	(	struct lws_context *	context,
		void *	buf,
		int	len
	)

#include <lib/libwebsockets.h>

lws_get_random(): fill a buffer with platform random data

Parameters

context	the lws context
buf	buffer to fill
len	how much to fill

This is intended to be called from the LWS_CALLBACK_RECEIVE callback if it's interested to see if the frame it's dealing with was sent in binary mode.

lws_now_secs()

LWS_VISIBLE LWS_EXTERN unsigned long lws_now_secs

(

void

)

#include <lib/libwebsockets.h>

lws_now_secs(): return seconds since 1970-1-1

lws_parse_uri()

LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT lws_parse_uri	(	char *	p,
		const char **	prot,
		const char **	ads,
		int *	port,
		const char **	path
	)

#include <lib/libwebsockets.h>

lws_parse_uri: cut up prot:/ads:port/path into pieces Notice it does so by dropping '\0' into input string and the leading / on the path is consequently lost

Parameters

p	incoming uri string.. will get written to
prot	result pointer for protocol part (https://)
ads	result pointer for address part
port	result pointer for port part
path	result pointer for path part

lws_set_allocator()

LWS_VISIBLE LWS_EXTERN void lws_set_allocator

(

void *(*)(void *ptr, size_t size)

realloc

)

#include <lib/libwebsockets.h>

lws_set_allocator() - custom allocator support

Parameters

realloc

Allows you to replace the allocator (and deallocator) used by lws

lws_snprintf()

LWS_VISIBLE LWS_EXTERN int lws_snprintf	(	char *	str,
		size_t	size,
		const char *	format,
			...
	)

#include <lib/libwebsockets.h>

lws_snprintf(): snprintf that truncates the returned length too

Parameters

str	destination buffer
size	bytes left in destination buffer
format	format string
...	args for format

This lets you correctly truncate buffers by concatenating lengths, if you reach the limit the reported length doesn't exceed the limit.

lws_wsi_user()

LWS_VISIBLE LWS_EXTERN void* lws_wsi_user

(

struct lws *

wsi

)

#include <lib/libwebsockets.h>

lws_wsi_user() - get the user data associated with the connection

Parameters

wsi	lws connection

Not normally needed since it's passed into the callback