libwebsockets-api-doc.html

<h2>libwebsocket_create_server - Create the listening websockets server</h2>
<i>int</i>
<b>libwebsocket_create_server</b>
(<i>int</i> <b>port</b>,
<i>int (*</i><b>callback</b>) <i>(struct libwebsocket *, 				enum libwebsocket_callback_reasons,  				void *, void *, size_t)</i>,
<i>int</i> <b>protocol</b>,
<i>size_t</i> <b>user_area_size</b>)
<h3>Arguments</h3>
<dl>
<dt><b>port</b>
<dd>Port to listen on
<dt><b>callback</b>
<dd>The callback in user code to perform actual serving
<dt><b>protocol</b>
<dd>Which version of the websockets protocol (currently 76)
<dt><b>user_area_size</b>
<dd>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.
</dl>
<h3>Description</h3>
<blockquote>
This function forks to create the listening socket and takes care
of all initialization in one step.
<p>
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.
<p>
The server created is a simple http server by default; part of the
websocket standard is upgrading this http connection to a websocket one.
<p>
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.
</blockquote>
<hr>
<h2>libwebsocket_get_uri - Return the URI path being requested</h2>
<i>const char *</i>
<b>libwebsocket_get_uri</b>
(<i>struct libwebsocket *</i> <b>wsi</b>)
<h3>Arguments</h3>
<dl>
<dt><b>wsi</b>
<dd>Websocket instance
</dl>
<h3>Description</h3>
<blockquote>
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"
</blockquote>
<hr>
<h2>libwebsocket_write - Apply protocol then write data to client</h2>
<i>int</i>
<b>libwebsocket_write</b>
(<i>struct libwebsocket *</i> <b>wsi</b>,
<i>unsigned char *</i> <b>buf</b>,
<i>size_t</i> <b>len</b>,
<i>enum libwebsocket_write_protocol</i> <b>protocol</b>)
<h3>Arguments</h3>
<dl>
<dt><b>wsi</b>
<dd>Websocket instance (available from user callback)
<dt><b>buf</b>
<dd>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.
<dt><b>len</b>
<dd>Count of the data bytes in the payload starting from buf
<dt><b>protocol</b>
<dd>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.
</dl>
<h3>Description</h3>
<blockquote>
This function provides the way to issue data back to the client
for both http and websocket protocols.
<p>
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.
</blockquote>
<hr>
<h2>libwebsockets_serve_http_file - Send a file back to the client using http</h2>
<i>int</i>
<b>libwebsockets_serve_http_file</b>
(<i>struct libwebsocket *</i> <b>wsi</b>,
<i>const char *</i> <b>file</b>,
<i>const char *</i> <b>content_type</b>)
<h3>Arguments</h3>
<dl>
<dt><b>wsi</b>
<dd>Websocket instance (available from user callback)
<dt><b>file</b>
<dd>The file to issue over http
<dt><b>content_type</b>
<dd>The http content type, eg, text/html
</dl>
<h3>Description</h3>
<blockquote>
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.
</blockquote>
<hr>