README-test-server

Using test-server as a quickstart
---------------------------------

For a Fedora x86_86 box, the following config line was
needed:

 ./configure --prefix=/usr --libdir=/usr/lib64 --enable-openssl

For Apple systems, Christopher Baker reported that this is needed
(and I was told separately enabling openssl makes trouble somehow)

./configure CC="gcc -arch i386 -arch x86_64" CXX="g++ -arch i386 -arch
x86_64" CPP="gcc -E" CXXCPP="g++ -E" --enable-nofork


otherwise if /usr/local/... and /usr/local/lib are OK then...

$ ./configure
$ make clean
$ make
$ sudo make install
$ libwebsockets-test-server

should be enough to get a test server listening on port 7861.

There are a couple of other possible configure options

--enable-nofork		disables the fork into the background API
			and removes all references to fork() and
			pr_ctl() from the sources.  Use it if your
			platform doesn't support forking.

--enable-libcrypto	by default libwebsockets uses its own
			built-in md5 and sha-1 implementation for
			simplicity.  However the libcrypto ones
			may be faster, and in a distro context it
			may be highly desirable to use a common
			library implementation for ease of security
			upgrades.  Give this configure option
			to disable the built-in ones and force use
			of the libcrypto (part of openssl) ones.

--with-client-cert-dir=dir   tells the client ssl support where to
			     look for trust certificates to validate
			     the remote certificate against.

--enable-noping		Don't try to build the ping test app
			It needs some unixy environment that
			may choke in other build contexts, this
			lets you cleanly stop it being built

Testing server with a browser
-----------------------------

If you point your browser (eg, Chrome) to

  http://127.0.0.1:7681

It will fetch a script in the form of test.html, and then run the
script in there on the browser to open a websocket connection.
Incrementing numbers should appear in the browser display.

Using SSL on the server side
----------------------------

To test it using SSL/WSS, just run the test server with

$ libwebsockets-test-server --ssl

and use the URL

  https://127.0.0.1:7681

The connection will be entirely encrypted using some generated
certificates that your browser will not accept, since they are
not signed by any real Certificate Authority.  Just accept the
certificates in the browser and the connection will proceed
in first https and then websocket wss, acting exactly the
same.

test-server.c is all that is needed to use libwebsockets for
serving both the script html over http and websockets.


Forkless operation
------------------

If your target device does not offer fork(), you can use
libwebsockets from your own main loop instead.  Use the
configure option --nofork and simply call libwebsocket_service()
from your own main loop as shown in the test app sources.


Testing websocket client support
--------------------------------

If you run the test server as described above, you can also
connect to it using the test client as well as a browser.

$ libwebsockets-test-client localhost

will by default connect to the test server on localhost:7681
and print the dumb increment number from the server at the
same time as drawing random circles in the mirror protocol;
if you connect to the test server using a browser at the
same time you will be able to see the circles being drawn.


Testing SSL on the client side
------------------------------

To test SSL/WSS client action, just run the client test with

$ libwebsockets-test-client localhost --ssl

By default the client test applet is set to accept selfsigned
certificates used by the test server, this is indicated by the
use_ssl var being set to 2.  Set it to 1 to reject any server
certificate that it doesn't have a trusted CA cert for.


Using the websocket ping utility
--------------------------------

libwebsockets-test-ping connects as a client to a remote
websocket server using 04 protocol and pings it like the
normal unix ping utility.

$ libwebsockets-test-ping localhost                
handshake OK for protocol lws-mirror-protocol
Websocket PING localhost.localdomain (127.0.0.1) 64 bytes of data.
64 bytes from localhost: req=1 time=0.1ms
64 bytes from localhost: req=2 time=0.1ms
64 bytes from localhost: req=3 time=0.1ms
64 bytes from localhost: req=4 time=0.2ms
64 bytes from localhost: req=5 time=0.1ms
64 bytes from localhost: req=6 time=0.2ms
64 bytes from localhost: req=7 time=0.2ms
64 bytes from localhost: req=8 time=0.1ms
^C
--- localhost.localdomain websocket ping statistics ---
8 packets transmitted, 8 received, 0% packet loss, time 7458ms
rtt min/avg/max = 0.110/0.185/0.218 ms
$

By default it sends 64 byte payload packets using the 04
PING packet opcode type.  You can change the payload size
using the -s= flag, up to a maximum of 125 mandated by the
04 standard.

Using the lws-mirror protocol that is provided by the test
server, libwebsockets-test-ping can also use larger payload
sizes up to 4096 is BINARY packets; lws-mirror will copy
them back to the client and they appear as a PONG.  Use the
-m flag to select this operation.

The default interval between pings is 1s, you can use the -i=
flag to set this, including fractions like -i=0.01 for 10ms
interval.

Before you can even use the PING opcode that is part of the
standard, you must complete a handshake with a specified
protocol.  By default lws-mirror-protocol is used which is
supported by the test server.  But if you are using it on
another server, you can specify the protcol to handshake with
by --protocol=protocolname


proxy support
-------------

The http_proxy environment variable is respected by the client
connection code for both ws:// and wss://.  It doesn't support
authentication yet.

You use it like this

export http_proxy=myproxy.com:3128
libwebsockets-test-client someserver.com


Websocket version supported
---------------------------

The websocket client code is 04 and 05 version, the server
supports 00/76 in text mode and 04 and 05 dynamically
per-connection depending on the version of the
client / browser.


External Polling Loop support
-----------------------------

libwebsockets maintains an internal poll() array for all of its
sockets, but you can instead integrate the sockets into an
external polling array.  That's needed if libwebsockets will
cooperate with an existing poll array maintained by another
server.

Four callbacks LWS_CALLBACK_ADD_POLL_FD, LWS_CALLBACK_DEL_POLL_FD,
LWS_CALLBACK_SET_MODE_POLL_FD and LWS_CALLBACK_CLEAR_MODE_POLL_FD
appear in the callback for protocol 0 and allow interface code to
manage socket descriptors in other poll loops.

2011-02-12  Andy Green <andy@warmcat.com>