Front-end support for gem-based themes

[ashmaroli]

(Contains diff from #344 as well) Front-end support to easily view templates within theme-gems via the interface.

-- @benbalter I'm proposing a set of front-end code to demonstrate my intention behind #344 /cc @mertkahyaoglu

[mertkahyaoglu]

Wow. That's perfect 👍

I think it would be super useful if we can edit the theme files. Otherwise I don't see the point viewing them ( :+1: for key-value part though ).

[ashmaroli]

I also wanted to include a Button to easily copy a template from the gem to the source_dir with error messages informing / warning users if that template path already exists in the source_dir. But ultimately decided to leave it out for now.

Thanks for your feedback anyways, @mertkahyaoglu. Appreciate it. :smiley:

[benbalter]

@ashmaroli I asked a few questions over in https://github.com/jekyll/jekyll-admin/pull/344#issuecomment-293915592:

That helps to understand what you want the API to do, but what user-facing functionality are you trying to provide? What problem are you trying to solve for? What workflow are you trying to support?

If I'm understanding correctly, I'm a bit concerned about leapfrogging over the significantly more common use case of editing template within the site (nearly every site, but not a use case the current editor experience is optimized for), to the much less common use case of authoring a theme that exists elsewhere on the user's computer.

[ashmaroli]

I asked a few questions over in [...]

@benbalter This PR was meant to be an answer to your questions in that comment. But looks like we keep misinterpreting each other. So, I'll try to answer your questions verbally in the following comment..

[ashmaroli]

What user-facing functionality are you trying to provide?

Allow users to view theme-gem contents via the admin interface. In future, copy a template file from theme-gem to source_dir with a button-click.

--

What problem are you trying to solve for?

A feature enabled by default in JekyllCore (theme-gems) is not present even in basic form via the admin interface.

--

What workflow are you trying to support?

TBH, this is not part of a workflow. Rather, a feature for completion sake. Users need not traverse multiple directories to view their theme-gem contents.(I myself have my GEM_HOME defined on a different drive on my Windows system.) They may do so via the admin interface with a few clicks.