[IPython-dev] ipython with sync
Thu Sep 12 18:04:26 CDT 2013
On Thu, Sep 12, 2013 at 2:53 PM, Brian Granger <email@example.com> wrote:
> Thanks for notes. This is really exciting and we are very interested
> in getting live sync to work with IPython itself. I am traveling this
> week, but will try to have a look soon. Is the code available
> somewhere to look at?
Unfortunately, this implementation is very entangled as part of
something I'm building as part of a startup company with UW's Center
for commercialization, and I can't just open source everything. But
the algorithm is here:
and the author of that paper has an open source Python implementation,
> On Tue, Sep 10, 2013 at 9:11 AM, William Stein <firstname.lastname@example.org> wrote:
>> Somewhat by accident I spent the last two weeks implementing hosted
>> IPython notebooks with sync for https://cloud.sagemath.com.
>> Initially I had just plan to simplify the port forwarding setup, since
>> what Ondrej Certik was doing with multiple forward and reverse port
>> forwards seemed complicated. But then I became concerned about
>> multiple users (or users with multiple browsers) overwriting each
>> other's notebooks, because cloud.sagemath projects are frequently
>> shared between multiple people, and everything else does realtime
>> sync. I had planned just to add some very minimal merge-on-save
>> functionality to avoid major issues, but somehow got sucked into
>> realtime sync (even with the other person's cursor showing).
>> It would be enormously helpful to me if a couple of expert IPython
>> users were to try out what I implemented and just ask a bunch of
>> 1. Go to https://cloud.sagemath.com and make an account; this is
>> completely free, and is hosted on computers at University of
>> 2. Create a new project.
>> 3. Click +New, then click "IPython" (or paste in a link to an ipython
>> notebook, or upload a file).
>> 4. An IPython notebook server will start, the given .ipynb file should
>> load in a same-domain iframe, and then some of the ipython notebook
>> code is and iframe contents are monkey patched, in order to support
>> sync and better integration with https://cloud.sagemath.com.
>> 5. Open the ipynb file in multiple browsers, and see that changes in
>> one appear in the other, including moving cells around, creating new
>> cells, editing markdown (the rendered version appears elsewhere), etc.
>> Anything that sets the notebook.dirty flag in IPython causes a sync
>> (evaluating a cell that creates no output doesn't set this flag, at
>> least in 1.0.0, which is a bug in IPython, I guess).
>> Since this is all very new and the first (I guess) realtime sync
>> implementation on top of IPython, there are probably a lot of issues.
>> Note that if you click the "i" info button to the right, you'll get a
>> link to the standard IPython
>> The other thing of interest is a little Python script called
>> "ipython-notebook", which I wrote. It basically makes it easy to run
>> an IPython notebook server as a daemon, get the port it is running on,
>> etc. It's pretty simple but satisfies my use case, and has
>> JSON-output, to make it web friendly. As I've written it, my script
>> passes several base_url options through by default, which are needed
>> for cloud.sagemath. Anyway, I've attached it to this email (with a
>> BSD license) in case there is any interest.
>> Regarding the monkey patching in 4 above, the right thing to do would
>> be to explain exactly what hooks/changes in the IPython html client I
>> need in order to do sync, etc., make sure these makes sense to the
>> IPython devs, and send a pull request (or have a coding sprint in
>> Seattle or Berkeley?). As an example, in order to do sync
>> *efficiently*, I have to be able to set a given cell from JSON -- it's
>> critical to do this in place when possible, since the overhead of
>> creating a new cell is huge (due probably to the overhead of creating
>> CodeMirror editors); however, the fromJSON method in IPython assumes
>> that the cell is brand new -- it would be nice to add an option to
>> make a cell fromJSON without assuming it is empty.
>> The ultimate outcome of this could be a clean well-defined way of
>> doing sync for IPython notebooks using any third-party sync
>> implementation. IPython might provide their own sync service and
>> there are starting to be others available these days -- e.g., Google
>> has one: https://developers.google.com/drive/realtime/, and maybe
>> Guido van Rosum helped write one for Dropbox recently?
>> Subdirectories: I noticed, incidentally, that the wakari version of
>> the IPython notebook server allows one to load ipynb files that are in
>> any subdirectory, whereas the standard IPython notebook server
>> doesn't. For cloud.sagemath, I just spawn a new IPython notebook
>> server for each directory that a user accesses files in right now.
>> This seems cludgy, so I'm interested in the situation regarding adding
>> support for subdirectories.
>> -- William
>> William Stein
>> Professor of Mathematics
>> University of Washington
>> IPython-dev mailing list
> Brian E. Granger
> Cal Poly State University, San Luis Obispo
> email@example.com and firstname.lastname@example.org
> IPython-dev mailing list
Professor of Mathematics
University of Washington
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