offline only cufflinks with no dependency on chart_studio

[mrmathematica]

This is related to #196

cufflinks 0.17.0 depends on chart_studio, in particular I found two import of chart_studio in the code

https://github.com/santosjorge/cufflinks/search?q=chart_studio&unscoped_q=chart_studio

Since plotly is pure offline now, and cufflinks can go_offline, we don't want the dependency on chart_studio. Actually in our environment we can't install chart_studio. I think this is the reason why it is split out of plotly at the first place.

So this is kind of a feature request: please make the chart_studio dependency conditional. By default it goes into offline mode, and chart_studio code is needed at all.

I tried to patch 0.17.0 myself, replacing cufflinks/init.py line 23 from
from chart_studio.plotly import plot
to
from plotly.offline import plot
and replacing cufflinks/plotlytools.py line 2 from
import chart_studio.plotly as py
to
import plotly.offline as py

it doesn't really work. For example I get

In [1]: import cufflinks as cf

In [2]: cf.go_offline()

In [3]: fig=cf.datagen.histogram(3).figure(kind='histogram ')

In [4]: cf.iplot(fig,online=True)

TypeError Traceback (most recent call last)
in
----> 1 cf.iplot(fig,online=True)

cufflinks/0.17.0/lib/cufflinks/plotlytools.py in iplot(figure, validate, sharing, filename, online, asImage, asUrl, asPlot, dimensions, display_image, **kwargs)
1464 else:
1465 return py.iplot(figure,validate=validate,sharing=sharing,
-> 1466 filename=filename)
1467
1468

TypeError: iplot() got an unexpected keyword argument 'sharing'

I assume this is due to API difference between plotly.offline and chart_studio.plotly. So this request is about to make it all depends on plotly.offline API.

[nicolaskruchten]

In principle I support this. I think we should do this in v0.18 so that v0.17 is minimally different from v0.16.

[nicolaskruchten]

This is partly addressed in #211, which makes the chart_studio dependency optional.