Adds *must* use routing proxy to guidelines

[afred]

Closes #23.

[afred]

@projecthydra-labs/hydra_plugins_wg review and merge?

[afred]

@jcoyne justification is mentioned in the issue comments.

Since the the implicit routing proxy changes depending on context, I think it's better if the plugin developer does not assume what that context is.

Perhaps it should be reworded to say:

When using URL helpers generated by Rails routes, plugins should use the explicit routing helper, and should not use the implicit routing helper.

Also, an example of a "good" vs "bad" code snippet here would probably be helpful.

[jcoyne]

This goes against idiomatic rails practices :-1:

[afred]

@jcoyne how is it going against idiomatic rails?

[mbarnett]

I'd love to see a citation on routing proxies being unidiomatic. It's a solution explicitly endorsed in the Rails Guides.

The major "idiomatic" Rails code bases use it quite a bit. Spree uses it extensively, to point at a well-known example.

[jcoyne]

You'll notice that none of the examples here use the explicit main_app route proxy: http://guides.rubyonrails.org/routing.html#path-and-url-helpers

Engines can be considered miniature applications that provide functionality to their host applications. A Rails application is actually just a "supercharged" engine, with the Rails::Application class inheriting a lot of its behavior from Rails::Engine.

• http://guides.rubyonrails.org/engines.html

So, if Rails::Application is a subclass of Rails::Engine, one should always prefix any route helper with main_app? That is not something I'm seeing.

[afred]

So...

• Rails Guides for Engines say to explicitly use the routing proxies, or else you may get unexpected links, or no method errors, but...
• Rails Guides for general routing simply do not mention using routing proxies at all.

For plugins that are Engines, I think it's more prudent to follow the Rails docs for Engines, yeah?

I can't think of a situation where it would be safer, or better code, to leave off the routing proxy and just assume that the implicit routing proxy is the one you want.

[afred]

@projecthydra-labs/hydra_plugins_wg can we get 👍 or 👎 on this from our group? So far, we have just one, from @mbarnett. Thanks!

[afred]

PR modifications needed:

• Justification is added. Basically, something that reiterates and/or refers to the established guidelines for using routes with Rails Engines.

• Change guideline verbiage from

  Plugins must specify...

  to

  Plugins that are Rails Engines must specify..."

[cjcolvar]

:+1: