libwebsockets-api-doc.txt

Name:

libwebsocket_create_server - Create the listening websockets server

Synopsis:

int libwebsocket_create_server (int port,
                                int (*callback) (struct libwebsocket *, 				enum libwebsocket_callback_reasons,  				void *, void *, size_t,
                                int protocol,
                                size_t user_area_size);

Arguments:

port
	Port to listen on

callback
	The callback in user code to perform actual serving

protocol
	Which version of the websockets protocol (currently 76)

user_area_size
	How much memory to allocate per connection session
which will be used by the user application to store
per-session data.  A pointer to this space is given
when the user callback is called.


Description:

This function forks to create the listening socket and takes care
of all initialization in one step.

The callback function is called for a handful of events including
http requests coming in, websocket connections becoming
established, and data arriving; it's also called periodically to allow
async transmission.

The server created is a simple http server by default; part of the
websocket standard is upgrading this http connection to a websocket one.

This allows the same server to provide files like scripts and favicon /
images or whatever over http and dynamic data over websockets all in
one place; they're all handled in the user callback.


Name:

libwebsocket_get_uri - Return the URI path being requested

Synopsis:

const char * libwebsocket_get_uri (struct libwebsocket * wsi);

Arguments:

wsi
	Websocket instance


Description:

The user code can find out the local path being opened from this
call, it's valid on HTTP or established websocket connections.
If the client opened the connection with "http://127.0.0.1/xyz/abc.d"
then this call will return a pointer to "/xyz/abc.d"


Name:

libwebsocket_write - Apply protocol then write data to client

Synopsis:

int libwebsocket_write (struct libwebsocket * wsi,
                        unsigned char * buf,
                        size_t len,
                        enum libwebsocket_write_protocol protocol);

Arguments:

wsi
	Websocket instance (available from user callback)

buf
	The data to send.  For data being sent on a websocket
connection (ie, not default http), this buffer MUST have
LWS_SEND_BUFFER_PRE_PADDING bytes valid BEFORE the pointer
and an additional LWS_SEND_BUFFER_POST_PADDING bytes valid
in the buffer after (buf + len).  This is so the protocol
header and trailer data can be added in-situ.

len
	Count of the data bytes in the payload starting from buf

protocol
	Use LWS_WRITE_HTTP to reply to an http connection, and one
of LWS_WRITE_BINARY or LWS_WRITE_TEXT to send appropriate
data on a websockets connection.  Remember to allow the extra
bytes before and after buf if LWS_WRITE_BINARY or LWS_WRITE_TEXT
are used.


Description:

This function provides the way to issue data back to the client
for both http and websocket protocols.

In the case of sending using websocket protocol, be sure to allocate
valid storage before and after buf as explained above.  This scheme
allows maximum efficiency of sending data and protocol in a single
packet while not burdening the user code with any protocol knowledge.


Name:

libwebsockets_serve_http_file - Send a file back to the client using http

Synopsis:

int libwebsockets_serve_http_file (struct libwebsocket * wsi,
                                   const char * file,
                                   const char * content_type);

Arguments:

wsi
	Websocket instance (available from user callback)

file
	The file to issue over http

content_type
	The http content type, eg, text/html


Description:

This function is intended to be called from the callback in response
to http requests from the client.  It allows the callback to issue
local files down the http link in a single step.