The dev tools available to web developers in modern browsers are great. Many of us can't remember what life was like before "Inspect Element". But what we see in the compiled output sent to our browser is often the wrong level of detail - what about visualizing the higher level components of your UI? Controllers, view templates, partials, JS templates, etc.

Xray is the missing link between the browser and your app code. Press command+shift+x (Mac) or ctrl+shift+x to reveal an overlay of the files that rendered your UI, and click anything to open the file in your editor.

Xray is intended for Rails 3.1+ and Ruby 1.9+.

So far, Xray can reveal:

• Rails views and partials
• Javascript templates if using the asset pipeline with the .jst extension

Xray depends on jQuery.

This gem should only be present during development. Add it to your Gemfile:

group :development do
  gem 'xray-rails'
end

Then bundle and delete your cached assets:

$ bundle && rm -rf tmp/cache/assets

Restart your app, visit it in your browser, and press command+shift+x (Mac) or ctrl+shift+x to reveal the overlay.

By default, Xray will insert itself into your views automatically. To do this, config.assets.debug = true (Rails' default) must be set in development.rb.

Otherwise, you can insert Xray's scripts yourself, for example like so in application.js:

//= require jquery
//= require xray

By default, Xray will check a few environment variables to determine which editor to open files in: $GEM_EDITOR, $VISUAL, then $EDITOR before falling back to /usr/local/bin/subl.

You can configure your editor of choice either by setting one of these variables, or in Xray's UI, or in an ~/.xrayconfig YAML file:

:editor: '/usr/local/bin/mate'

For something more complex, use the $file placeholder.

:editor: "/usr/local/bin/tmux new-window 'vim $file'"

• At run time, HTML responses from Rails are wrapped with HTML comments containing filepath info.
• A middleware inserts xray.js, xray.css, and the Xray bar into all successful HTML response bodies.
• When the overlay is shown, xray.js examines the inserted filepath info to build the overlay.

Xray augments HTML templates by wrapping their contents with HTML comments. For some environments such as Angular.js, this can cause Angular templates to stop working because Angular expects only one root node in the template HTML. You can pass in the option xray: false to any partial render statements to ensure Xray does not augment that partial. Example:

render partial: 'my_partial', locals: { xray: false }

Note that this disables Xray's HTML comment wrappers for my_partial, but not any sub-partials rendered within that template, if any. You must pass xray: false to each render call where you want Xray disabled.

Currently there is no way to disable Xray entirely for a given request. If this feature is important to you, please leave a comment on issue #75. PRs are appreciated!

If you have an idea, open an issue and let's talk about it, or fork away and send a pull request.

A laundry list of things to take on:

• Reveal views from Ember, Knockout, Angular, etc.
• Overlapping boxes are a problem - parent views in real applications will often be obscured by their children.
• The current scheme for associating a JS constructor with a filepath is messy and can make stack traces ugly.

Worth noting is that I have plans to solidify xray.js into an API and specification that could be used to aid development in any framework - not just Rails and the asset pipeline.