Serve SentEmailViewer static assets from a plug instead of CDN

[seivan]

Seems like normalize.css is served from some CDN. I'm a bit uncomfortable with having assets that we don't control, it would be nice if there was an opt in feature to allow us to serve that ourselves from a custom plug

Maybe there could be a config like:

config :my_app, MyApp.Mailer,
  adapter: Bamboo.LocalAdapter
  assets: "static"

Then you could just serve the file from /priv/static with a plug:

plug Plug.Static,
  at: "/assets/", from: :api, gzip: true,
  only: ~w(css fonts images js favicon.ico robots.txtn)

I don't mind wiring up a PR for this, if it's acceptable.

[germsvel]

Hi @seivan, I think this optional configuration could make sense and we can fallback to the CDN. It would be nice for it to work out of the box without configuration. Of course if you don't add normalize, then the preview emails might look different or slightly broken. I'm not actually sure to what extent the preview styles rely on normalize.css.

[DhananjayPurohit]

I found normalize.css not serving a lot to UI for SentEmailViewer hence implemented css being in use from CDN as internal css.

[seivan]

@germsvel I think the "out of the box" setting is to just bundle and serve it instead of relying on a third party CDN.

If it's not possible to set up a static plug at installation, then I don't see an issue with asking to implement:

plug Plug.Static,
  at: "/assets/", from: :api, gzip: true,
  only: ~w(css fonts images js favicon.ico robots.txtn)

Since the user still has to set other things up to use it.
If anything Bamboo could just make its own plug that wraps aforementioned configuration.

plug Bamboo.Assets,
  # Default settings 
  # at: "/assets/", from: :api, gzip: true, 
  # only: ~w(css fonts images js favicon.ico robots.txtn)