Move add_url function definition out of Dash.__init__()

[hinnefe2]

First of all, thanks for a great tool!

This PR moves the add_url utility function out of the __init__ method of the Dash class. This change makes it easier to subclass Dash.

My use case is adding authentication via flask_login. Pulling add_url out lets me subclass like so:

  class MyDash(Dash):                                                                                                                                                     
                                                               
      def add_url(self, name, view_func, methods=('GET',)):                                                                                                               
          self.server.add_url_rule(                                                                                                                                       
              name,                                                                                                                                                       
              view_func=login_required(view_func),                                                                                                                        
              endpoint=name,                                                                                                                                              
              methods=list(methods)                                                                                                                                       
          )  

Note that each view_func is wrapped by login_required so all my dash pages now require authentication.

I think this addresses some of the comments in #214.

[T4rk1n]

I'm ok with theses changes once the method is private.

[T4rk1n]

Make that "private" by prefixing with _.

[hinnefe2]

@T4rk1n Sorry for the delay, I think this is ready for another look. Thanks!

[T4rk1n]

@hinnefe2 I think your merge with master went bad, there is a line that should be in __init__ but is in the add_url method. Move back line 225-226 in __init__.

[T4rk1n]

Thanks, looks good now. 💃

Since this is for wrapping the routes in flask_login, you could add in the add_url method a way to save the route names. You can append the url name to self.routes, it is not used presently. Just make sure it is instanciated before the _add_url calls since it is at line 215. I would use that to solve plotly/dash-auth#59 if you do that.

Then instead of subclassing Dash, you can wrap the routes externally:

for view_name, view_method in (
        (x, app.server.view_functions[x])
        for x in app.routes
        if x in app.server.view_functions
    ):
    app.server.view_functions[view_name] = login_required(view_method)

@rmarren1 can you have a look too ?

[rmarren1]

I like this change. I don't see a drawback to defining add_url as a method of Dash rather than an internal function of __init__, and should give advanced users more flexibility.

Not sure why routes doesn't do anything right now, I think we should populate that in _add_url then we can merge this
💃

[hinnefe2]

@T4rk1n Ok, I think this is ready for another look. Thanks again for your patience!

[T4rk1n]

@hinnefe2 Great.

We got a new CONTRIBUTING guide, make sure to you have everything on the pre-merge checklist (update version.py and changelogs) to accelerate the merge/release process.

[hinnefe2]

Alright, changelog is updated and version is bumped, anything else for me to do?

[rmarren1]

Looks great, thanks! 🎊

[rmarren1]

Released dash==0.28.2