Page parameter pluto_server_url overrides default WebSocket address

[ctrekker]

The Pluto.jl desktop app needs a way to tell Pluto explicitly where to find a Pluto.jl WebSocket server running, since frontend assets are served directly from the filesystem (a file:https:// url). As far as I can tell, there was no way to do this already built into Pluto.jl, so this PR adds a page parameter to the editor and welcome screen which overrides the default websocket url behavior.

[github-actions]

Try this Pull Request!

Open Julia and type:

julia> import Pkg
julia> Pkg.activate(temp=true)
julia> Pkg.add(url="https://github.com/fonsp/Pluto.jl", rev="cb/desktop-app")
julia> using Pluto

[fonsp]

Nice! Can you re-use the pluto_server_url for this? Right now the only purpose is to define where a featured notebook preview should make the /open request, but maybe this setting can also be used as the "where is the WS server" setting.

If that doesn't work then lets go for this!

[ctrekker]

Adding websocket-related behavior for pluto_server_url will work, at least for PlutoDesktop! My only worry is that these changes may cause issues for binder. I'm not sure how to test these changes on binder without them being included in a release

[fonsp]

You can test binder by generating a test URL yourself, e.g.

https://localhost:1235/editor.html?statefile=https%3A%2F%2Fcdn.jsdelivr.net%2Fgh%2FJuliaPluto%2Ffeatured%40v2%2Fbasic%2FInteractivity.plutostate&notebookfile=https%3A%2F%2Fcdn.jsdelivr.net%2Fgh%2FJuliaPluto%2Ffeatured%40v2%2Fbasic%2FInteractivity.jl&disable_ui=true&binder_url=https%3A%2F%2Fmybinder.org%2Fv2%2Fgh%2Ffonsp%2Fpluto-on-binder%2Fv0.19.23

I'm testing it right now, but it should definitely work. Featured notebooks also still work 👍

[fonsp]

Binder still works 👍