Uploading a file from client to server in python bokeh
I'm not sure where you are getting your information. The FileInput widget added in Bokeh 1.3.0 can upload any file the user chooses, not just JSON.
We have set up a bokeh server in our institute, which works properly. We also have a python-based code to analyse fMRI data which at the moment uses matplotlib to plot and save. But I want to transfer the code to bokeh server and allow everybody to upload files into the server from the client and when the analysis is done in the server, save the output plots in their local HDD. This transfer file procedure seems to be lacking in bokeh atm. I saw a new feature recently added in github to upload json files, but my problem is fMRI files come in various formats, and asking (not necessarily tech-savvy) users to convert the files into a certain format beats the purpose. Also, I do not know any JS or the like, hence I do not know what solutions people usually use for such web-based applications. 
If anybody has any solutions to get around this issue, it'd be happy to hear it. Even if it is a solution independent of bokeh (which would mean users need to open a separate page to upload the files, a page to run the analysis, and a page to save the output) please let me know. It won't be ideal, but at least better than no solution, which is the case in bokeh right now. Thanks!