T1t0 at 00:44, 14 March 2021

2021-03-14T00:44:02Z

← Older revision		Revision as of 00:44, 14 March 2021
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	* [http://git.warmcat.com/cgi-bin/cgit/libwebsockets/ libwebsockets - C Websockets Server Library]		* [http://git.warmcat.com/cgi-bin/cgit/libwebsockets/ libwebsockets - C Websockets Server Library]
	* [http://martinsikora.com/libwebsockets-simple-websocket-server libwebsockets: Simple WebSocket server]		* [http://martinsikora.com/libwebsockets-simple-websocket-server libwebsockets: Simple WebSocket server]



	[[Category:develop]]		[[Category:develop]]
	[[Category:cpp]]		[[Category:c/cpp]]
	[[Category:web]]		[[Category:web]]

T1t0 at 03:28, 14 February 2021

2021-02-14T03:28:41Z

← Older revision		Revision as of 03:28, 14 February 2021
Line 276:		Line 276:

	[[Category:develop]]		[[Category:develop]]
	[[Category:~~c++~~]]		[[Category:cpp]]
	[[Category:web]]		[[Category:web]]

imported>T1t0 at 11:40, 1 September 2014

2014-09-01T11:40:26Z

← Older revision		Revision as of 11:40, 1 September 2014
Line 238:		Line 238:
	== Configure Index ==		== Configure Index ==

	~~<pre>~~		: Project -> Properties
	# Project -> Properties		: C/C++ General -> Paths and Symbols
	# C/C++ General -> Paths and Symbols		: switch to tab 'Includes'
	# switch to tab 'Includes'		: select 'GNU C++' an click 'Add...'
	# select 'GNU C++' an click 'Add...'		: Directory: "/usr/local/libwebsockets/include"
	# Directory: "/usr/local/libwebsockets/include"		: click 'OK'
	# click 'OK'		: switch to tab 'Library Paths'
	# switch to tab 'Library Paths'		: click 'Add...'
	# click 'Add...'		: Directory: "/usr/local/libwebsockets/lib"
	# Directory: "/usr/local/libwebsockets/lib"		: 'OK'
	~~# click~~ 'OK'		: click 'OK' again
	# click 'OK' again
	~~</pre>~~


Line 256:		Line 254:
	== Configure to Run and Debug ==		== Configure to Run and Debug ==

	~~<pre>~~		: Run -> Debug Configurations
	# Run -> Debug Configurations		: select 'C/C++ Application'
	# select 'C/C++ Application'		: click on 'New launch configuration'
	# click on 'New launch configuration'		: Name: "TestLibWebsockets Debug"
	# Name: "TestLibWebsockets Debug"		: C/C++ Application: "TestLibWebsockets/build/debug/TestLibWebsockets"
	# C/C++ Application: "TestLibWebsockets/build/debug/TestLibWebsockets"		: switch to tab 'Environment'
	# switch to tab 'Environment'		: click New...
	# click New...		: Name: "LD_LIBRARY_PATH"
	# Name: "LD_LIBRARY_PATH"		: Value: "/usr/local/libwebsockets/lib/"
	# Value: "/usr/local/libwebsockets/lib/"		: click Ok
	# click Ok		: click on Close
	# click on Close
	~~</pre>~~

imported>T1t0 at 13:29, 10 December 2012

2012-12-10T13:29:08Z

← Older revision		Revision as of 13:29, 10 December 2012
Line 13:		Line 13:

	= Build and install =		= Build and install =

			NOTE: choose a destination path, I use /usr/local/libwebsockets

	<pre>		<pre>
Line 25:		Line 27:
	./autogen.sh		./autogen.sh
	./configure --prefix=/usr/local/libwebsockets --enable-openssl --enable-libcrypto		./configure --prefix=/usr/local/libwebsockets --enable-openssl --enable-libcrypto
			make
	make install		make install
	</pre>		</pre>

imported>T1t0: Created page with "= Environment =

 # cat /etc/debian_version  6.0.6 # gcc -v gcc version 4.4.5 (Debian 4.4.5-8)  # uname -r 3.2.0-0.bpo.3-amd64

= Build and install =

 apt-..."

2012-12-07T04:45:00Z

Created page with "= Environment = <pre> # cat /etc/debian_version 6.0.6 # gcc -v gcc version 4.4.5 (Debian 4.4.5-8) # uname -r 3.2.0-0.bpo.3-amd64 </pre> = Build and install = <pre> apt-..."

New page

= Environment =

<pre>
# cat /etc/debian_version
6.0.6
# gcc -v
gcc version 4.4.5 (Debian 4.4.5-8)
# uname -r
3.2.0-0.bpo.3-amd64
</pre>

= Build and install =

<pre>
apt-get install libtool libssl-dev
mkdir /usr/local/libwebsockets
chown nobody:nogroup /usr/local/libwebsockets
su -s /bin/bash nobody
cd /tmp
wget http://git.warmcat.com/cgi-bin/cgit/libwebsockets/snapshot/libwebsockets-788c4a8fa847ce7f6900e529af73f1aed7311ccc.tar.gz
tar -xzf libwebsockets-788c4a8fa847ce7f6900e529af73f1aed7311ccc.tar.gz
cd libwebsockets-788c4a8fa847ce7f6900e529af73f1aed7311ccc
./autogen.sh
./configure --prefix=/usr/local/libwebsockets --enable-openssl --enable-libcrypto
make install
</pre>

= First libwebsocket app =

== sources ==

from https://gist.github.com/3654228

* main.c:

<pre>
#include <stdio.h>
#include <stdlib.h>
#include <libwebsockets.h>

static int callback_http(struct libwebsocket_context * this_context,
struct libwebsocket *wsi,
enum libwebsocket_callback_reasons reason, void *user,
void *in, size_t len)
{
return 0;
}

static int callback_dumb_increment(struct libwebsocket_context * this_context,
struct libwebsocket *wsi,
enum libwebsocket_callback_reasons reason,
void *user, void *in, size_t len)
{
switch (reason)
{
case LWS_CALLBACK_ESTABLISHED: // just log message that someone is connecting
printf("connection established\n");
break;
case LWS_CALLBACK_RECEIVE: // the funny part
{
// create a buffer to hold our response
// it has to have some pre and post padding. You don't need to care
// what comes there, libwebsockets will do everything for you. For more info see
// http://git.warmcat.com/cgi-bin/cgit/libwebsockets/tree/lib/libwebsockets.h#n597
unsigned char *buf = (unsigned char*) malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
LWS_SEND_BUFFER_POST_PADDING);

int i;

// pointer to `void *in` holds the incomming request
// we're just going to put it in reverse order and put it in `buf` with
// correct offset. `len` holds length of the request.
for (i=0; i < len; i++)
{
buf[LWS_SEND_BUFFER_PRE_PADDING + (len - 1) - i ] = ((char *) in)[i];
}

// log what we recieved and what we're going to send as a response.
// that disco syntax `%.*s` is used to print just a part of our buffer
// http://stackoverflow.com/questions/5189071/print-part-of-char-array
printf("received data: %s, replying: %.*s\n", (char *) in, (int) len,
buf + LWS_SEND_BUFFER_PRE_PADDING);

// send response
// just notice that we have to tell where exactly our response starts. That's
// why there's `buf[LWS_SEND_BUFFER_PRE_PADDING]` and how long it is.
// we know that our response has the same length as request because
// it's the same message in reverse order.
libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], len, LWS_WRITE_TEXT);

// release memory back into the wild
free(buf);
break;
}
default:
break;
}

return 0;
}

static struct libwebsocket_protocols protocols[] =
{
/* first protocol must always be HTTP handler */
{
"http-only", // name
callback_http, // callback
0 // per_session_data_size
},
{
"dumb-increment-protocol", // protocol name - very important!
callback_dumb_increment, // callback
0 // we don't use any per session data
},
{
NULL, NULL, 0 /* End of list */
}
};

int main(void)
{
// server url will be http://localhost:9000
int port = 9000;
const char *interface = NULL;
struct libwebsocket_context *context;
// we're not using ssl
const char *cert_path = NULL;
const char *key_path = NULL;
// no special options
int opts = 0;

// create libwebsocket context representing this server
context = libwebsocket_create_context(port, interface, protocols,
libwebsocket_internal_extensions,
cert_path, key_path, -1, -1, opts, NULL);

if (context == NULL)
{
fprintf(stderr, "libwebsocket init failed\n");
return -1;
}

printf("starting server...\n");

// infinite loop, to end this server send SIGTERM. (CTRL+C)
while (1)
{
libwebsocket_service(context, 50);
// libwebsocket_service will process all waiting events with their
// callback functions and then wait 50 ms.
// (this is a single threaded webserver and this will keep our server
// from generating load while there are not requests to process)
}

libwebsocket_context_destroy(context);

return 0;
}
</pre>

* index.html
<pre>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
$(function() {
window.WebSocket = window.WebSocket || window.MozWebSocket;

var websocket = new WebSocket('ws://127.0.0.1:9000',
'dumb-increment-protocol');

websocket.onopen = function () {
$('h1').css('color', 'green');
};

websocket.onerror = function () {
$('h1').css('color', 'red');
};

websocket.onmessage = function (message) {
console.log(message.data);
$('div').append($('<p>', { text: message.data }));
};

$('button').click(function(e) {
e.preventDefault();
websocket.send($('input').val());
$('input').val('');
});
});
</script>
</head>
<body>
<h1>WebSockets test</h1>
<form>
<input type="text" />
<button>Send</button>
</form>
<div></div>
</body>
</html>

</pre>

== Compile and run ==

<pre>
gcc -o test main.c -I /usr/local/libwebsockets/include/ -L /usr/local/libwebsockets/lib/ -lwebsockets
LD_LIBRARY_PATH=/usr/local/libwebsockets/lib ./test
</pre>

= Set-up an Eclipse CDT project ==

Create an Eclipse project, maybe like [[Eclipse CDT|there]]

== Configure Index ==

<pre>
# Project -> Properties
# C/C++ General -> Paths and Symbols
# switch to tab 'Includes'
# select 'GNU C++' an click 'Add...'
# Directory: "/usr/local/libwebsockets/include"
# click 'OK'
# switch to tab 'Library Paths'
# click 'Add...'
# Directory: "/usr/local/libwebsockets/lib"
# click 'OK'
# click 'OK' again
</pre>

== Configure to Run and Debug ==

<pre>
# Run -> Debug Configurations
# select 'C/C++ Application'
# click on 'New launch configuration'
# Name: "TestLibWebsockets Debug"
# C/C++ Application: "TestLibWebsockets/build/debug/TestLibWebsockets"
# switch to tab 'Environment'
# click New...
# Name: "LD_LIBRARY_PATH"
# Value: "/usr/local/libwebsockets/lib/"
# click Ok
# click on Close
</pre>

= References =

* [http://git.warmcat.com/cgi-bin/cgit/libwebsockets/ libwebsockets - C Websockets Server Library]
* [http://martinsikora.com/libwebsockets-simple-websocket-server libwebsockets: Simple WebSocket server]

[[Category:develop]]
[[Category:c++]]
[[Category:web]]

Libwebsockets - Revision history

T1t0 at 00:44, 14 March 2021

T1t0 at 03:28, 14 February 2021

imported>T1t0 at 11:40, 1 September 2014

imported>T1t0 at 13:29, 10 December 2012

imported>T1t0: Created page with "= Environment =
# cat /etc/debian_version 6.0.6 # gcc -v gcc version 4.4.5 (Debian 4.4.5-8) # uname -r 3.2.0-0.bpo.3-amd64
= Build and install =
apt-..."