CherryPy and websockets

[Vincent Le Goff]

Hi everyone,

I tried to find the answer on the Web but didn't come out with a lot
of informations: could CherryPy support websockets, be a webserver and
a websocket server listening on the same port?

Is that already possible on Cherrypy or is it a work in progress? Or,
on the other hand, could this functionality be implemented in a kind
of extension or plugin?

Happy hacking,

Vincent

[Sylvain Hellegouarch]

Hi Vincent,

CherryPy doesn't implement WebSocket indeed but I wrote a small package that works rather well and implements RFC 6455.

ws4py: https://github.com/Lawouach/WebSocket-for-Python

Note that only the official protocol is supported not older broken version, which means that some browser won't work with ws4py. See: http://caniuse.com/websockets

ws4py runs on top of CherryPy 3.2.x with Python 2x and 3.x.

--
- Sylvain
http://www.defuze.org
http://twitter.com/lawouach

[Vincent Le Goff]

Hi Sylvain,

Thanks, that's great, really great :D . I just have an error while
trying the echo_cherrypy example.

I have CherryPy 3.2 (Python 3.2). The example does start and
everything's working fine until I launch Firefox on localhost:9000.
Here's the error:

[30/Oct/2012:17:26:59] HTTP Traceback (most recent call last):
File "C:\python32\lib\site-packages\cherrypy-3.2.2-py3.2.egg\cherrypy\_cpreque
st.py", line 647, in respond
self.hooks.run('before_request_body')
File "C:\python32\lib\site-packages\cherrypy-3.2.2-py3.2.egg\cherrypy\_cpreque
st.py", line 112, in run
raise exc
File "C:\python32\lib\site-packages\cherrypy-3.2.2-py3.2.egg\cherrypy\_cpreque
st.py", line 102, in run
hook()
File "C:\python32\lib\site-packages\cherrypy-3.2.2-py3.2.egg\cherrypy\_cpreque
st.py", line 62, in __call__
return self.callback(**self.kwargs)
File "C:\python32\lib\site-packages\ws4py-0.2.3-py3.2.egg\ws4py\server\cherrypyserver.py",
line 149, in upgrade
ws_key = base64.b64decode(key)
File "C:\python32\lib\base64.py", line 83, in b64decode
raise TypeError("expected bytes, not %s" % s.__class__.__name__)
TypeError: expected bytes, not str
127.0.0.1 - - [30/Oct/2012:17:26:59] "GET /ws HTTP/1.1" 500 1686 "" "Mozilla/5.0

Maybe it's because the Python 3 sockets exchange bytes, no more str,
but I doubt of it, as Cherrypy handles it well. Do you know where
this problem come from?

Thanks again,

Vincent

2012/10/30, Sylvain Hellegouarch <s...@defuze.org>:

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[Sylvain Hellegouarch]

Hi Vincent,

I'll admit that I've mostly worked against Python 3.3 and may have overlooked a few things with 3.2. I will try to see that this evening. Note also that I'm usually running the latest CherryPy code rather than a stable version so that might be it as well. Damn :p

[Ralph Heinkel]

Hi Vincent,

we got websockets working really nicely with Sylvain's ws4py module.
However - and very unfortunately - we had to drop it again because the
websocket protocol was not supported by cherrypy behind mod_wsgi /
nginx at the time. I don't know what the situation is today, but I
doubt it has changed. I would love to see this working!

ciao ciao

Ralph

[Sylvain Hellegouarch]

Hi Ralph,

On Tue, Oct 30, 2012 at 6:32 PM, Ralph Heinkel <ralph....@web.de> wrote:

Hi Vincent,

we got websockets working really nicely with Sylvain's ws4py module.
However - and very unfortunately - we had to drop it again because the websocket protocol was not supported by cherrypy behind mod_wsgi / nginx at the time. I don't know what the situation is today, but I doubt it has changed. I would love to see this working!

It seems websockets is part of the 1.3 roadmap of nginx.  http://trac.nginx.org/nginx/roadmap

With a better support in nginx 1.2 for HTTP/1.1, maybe there is a chance reverse proxying now works well with websocket inside CherryPy.

[Sylvain Hellegouarch]

Hi Vincent,

I've reproduced the issue with Python 3.2 yesterday but didn't get a chance to fix it yet. Could you open a ticket on the ws4py github page please? 

Cheers,

[Vincent Le Goff]

Hi Sylvain and Ralph,

Sure, I'll do just that :) .

Thanks again for your work,

Vincent

2012/10/31, Sylvain Hellegouarch <s...@defuze.org>:

[Sylvain Hellegouarch]

Vincent,

On Wed, Oct 31, 2012 at 10:10 AM, Vincent Le Goff <vincent.l...@gmail.com> wrote:

Hi Sylvain and Ralph,

Sure, I'll do just that :) .

Thanks again for your work,

I've pushed a fix onto the repository. Could you try it by any chance?

 

[Vincent Le Goff]

Hi Sylvain,

The commit 54ab115d2db4a2d8f39475a14ff0062b386ea6e8 (fix #62) does not
solve the problem here, sorry :S .

Though, I tried to use sw4py on Python 3.3, installed it. The CherryPy
3.2.2 package doesn't work yet with Python 3.3.0 (at least not on
Windows) so I downloaded the last 'dev' version.

Your ech_cherrypy_server.py example works just fine under Python 3.3
and Cherrypy 3.2.3 (last dev). Maybe I should install the last
CherryPy version on python 3.2?

Thanks again for your work and your reactivity ;) ,

Vincent

2012/10/31, Sylvain Hellegouarch <s...@defuze.org>:

[Sylvain Hellegouarch]

On Wed, Oct 31, 2012 at 2:09 PM, Vincent Le Goff <vincent.l...@gmail.com> wrote:

Hi Sylvain,

The commit 54ab115d2db4a2d8f39475a14ff0062b386ea6e8 (fix #62) does not
solve the problem here, sorry :S .

Though, I tried to use sw4py on Python 3.3, installed it. The CherryPy
3.2.2 package doesn't work yet with Python 3.3.0 (at least not on
Windows) so I downloaded the last 'dev' version.

Your ech_cherrypy_server.py example works just fine under Python 3.3
and Cherrypy 3.2.3 (last dev).  Maybe I should install the last
CherryPy version on python 3.2?

Damn!

That's odd because I tried with Python 3.2 as provided by Ubuntu. Could you amend the ticket on github with any error you got with Python 3.2 after trying the last commit please? 

[Vincent Le Goff]

Actually it's the same error. But maybe it's due to my Cherrypy version.

Nevertheless, I'll try to find more informations

Vincent

2012/10/31, Sylvain Hellegouarch <s...@defuze.org>:

[Sylvain Hellegouarch]

Vincent,

On Wed, Oct 31, 2012 at 3:20 PM, Vincent Le Goff <vincent.l...@gmail.com> wrote:

Actually it's the same error. But maybe it's due to my Cherrypy version.

Nevertheless, I'll try to find more informations

I tried again this morning and it works well with Python 3.2.3, CherryPy 3.2.2 and ws4py 0.2.4 (current HEAD) against Firefox 16. 

Not sure what to tell you :)

[Vincent Le Goff]

Hi Sylvain,

I don't know what to tell me, either. But it's working now, with the
Cherrypy 3.2.3 development version.

Thanks again, wonderful work :) ,

Vincent

2012/11/3, Sylvain Hellegouarch <s...@defuze.org>:

[Sylvain Hellegouarch]

Hi Sander,

On Thu, Nov 8, 2012 at 11:11 AM, sanders <s.teu...@gmail.com> wrote:

Hi Sylvian,

I am facing the same issue.
So now I am trying to install version 0.24 (Cherrypy versions and Python version is the same). But a novice as I am, I downloaded the latest commit, but it has no setup.py with which I installed the 0.23 version....

Can you give me some guidance ?

Sure thing. I haven't yet released properly this new version so you'll have to grab the master branch. The easiest, if you don't have git, is to go to the download page: https://github.com/Lawouach/WebSocket-for-Python/downloads

This will get you ws4py with all you need. Simply run "python setup.py install" afterwards. 

Hope that helped.