[IPython-dev] Notebook websocket change

[William Stein]

On Thu, Jan 8, 2015 at 10:19 AM, Brian Granger <ellisonbg at gmail.com> wrote:
> So far we have felt that it isn't worth the complexity cost for us to
> support people that deliberately choose to break the internet. It is not
> like WebSockets is some crazy, insecure, unsupported hack over a weird port.
> It is just different bytes going over the same HTTP/HTTPS socket connection
> and is essentially a formal standard (I know you know this - this is our
> messaging to companies who complain).

I know -- that's why I switched SMC to pure websockets for a while.
Then I received complaints at a rate of about 2 very desperate users
per week, and these were the people who cared enough to complain
repeatedly.

> Our situation is a bit different though than SMC because most of our current
> users run the notebook on their own computers. This may be something that we
> eventually want to rethink as more people run this in the cloud. However, I
> would like to push back on the companies choosing to break the internet
> really hard before giving in. I am guessing that in most cases, WebSockets
> are broken in enterprise setting not because of some important deliberate
> choice, but rather because people don't understand it and are using default
> settings that disable them (I could be wrong though)....

In my experience, for some people that's exactly the problem.  For one
person I helped it turned out their specific problem was the Windows
install they had access to had websockets explicitly disabled --
perhaps that was an IT policy.  For other people the problem is
further along the stack (e.g., possibly involving caching).

Anyway, this change so that "there is a single websocket connection
between the server and client. " makes implementing an alternative to
WebSocket as a fallback dramatically easier, which I greatly
appreciate.

> Our situation is a bit different though than SMC because most of our current
> users run the notebook on their own computers. This may be something that we

Just curious -- how do you know that most people using IPython aren't
already using it through SMC?

William

>
> Cheers,
>
> Brian
>
>
>
> On Thu, Jan 8, 2015 at 10:10 AM, William Stein <wstein at gmail.com> wrote:
>>
>> On Thu, Jan 8, 2015 at 10:04 AM, MinRK <benjaminrk at gmail.com> wrote:
>> > Alternative notebook frontend authors:
>> >
>> > There is an upcoming change to websocket connections to the notebook
>> > server.
>> > Instead of three websockets per notebook, one for each zmq channel,
>> > there is
>> > a single websocket connection between the server and client. The channel
>> > associated with each message is identified by a channel key in the
>> > message
>> > dict itself.
>> >
>> > Relevant changes:
>> >
>> > url is /channels instead of /shell, etc.
>> > when sending a message, add a channel key with the channel name
>> > ('shell',
>> > 'stdin')
>> > when receiving a message, check the channel key for routing
>> >
>> > -MinRK
>>
>> Thanks.
>>
>> Of related interest, what the situation involving providing a fallback
>> to websockets?
>>
>> I tried to only support websockets connections with SageMathCloud for
>> a few weeks, and immediately ran into many complaints from users who
>> couldn't connect as a result.   This is even with https and so on --
>> it's just a sad fact that in some corporate or otherwise constrained
>> environments that websockets don't work.   By far the best approach I
>> found was to use Primus + Engine.io, which uses websockets if
>> possible, but will fallback to polling.   So this is what SMC does
>> now, and everything works, even for people that don't have websockets
>> as an option... except for IPython-in-SMC of course, which doesn't
>> work.
>>
>> Another unrelated issue is that I'm now hardcoding making this change
>> around line 171 of IPython/html/notebookapp.py, since I want to serve
>> the purely static html of IPython from a completely different web
>> server:
>>
>>             #static_url_prefix = url_path_join(base_url,'/static/'),
>>             static_url_prefix = '/static/ipython/',
>>
>> (Sorry for derailing the thread.)
>>
>>  -- William
>>
>> >
>> >
>> > _______________________________________________
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>> >
>>
>>
>>
>> --
>> William Stein
>> Professor of Mathematics
>> University of Washington
>> http://wstein.org
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>
>
>
>
> --
> Brian E. Granger
> Cal Poly State University, San Luis Obispo
> @ellisonbg on Twitter and GitHub
> bgranger at calpoly.edu and ellisonbg at gmail.com
>
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>



-- 
William Stein
Professor of Mathematics
University of Washington
http://wstein.org