the flask in SMC example is badly broken:

[williamstein]

Please help me to understand why the following example doesn't work:
https://github.com/sagemath/cloud-examples/blob/master/webservice/main.py

Wow, that's broken in many ways, due to it being written years ago and
a lot changing since then. I've rewritten it just now so it works:

https://cloud.sagemath.com/projects/4a5f0542-5873-4eed-a85c-a18c706e8bcd/files/support/2015-09-02-090517-webserver/

You should easily be able to use the above to get going with flask
development. Note that you have to prepend that "base_url" thing
before each url route. There's probably a proper way to do this with

[williamstein]

moved to sagemathinc/cocalc-example-files#14