Finding the source for a given Rails web page

These tips may help those of you who are relatively new to Rails, or maybe even if you’re not.

Common tips and tricks

• Look at the URL path (e.g. /users/100685/edit). Can the action and main view file be determined from CRUD/REST conventions?
  • /:model/edit -> edit.html.slim
  • /:model/1234 -> show.html.slim
  • /:model/new -> new.html.slim
  • /:model -> index.html.slim
• Look up the path in routes.rb, or even more useful, run rake routes

Finding a controller and action responsible for a given page

1. In development go to your server’s output, and clear the screen (Ctrl+L, for Linux, Cmd-K for OS X)
2. Refresh the web page
3. Back to the server’s output, scroll to the top of the output. About the second line of non-blank log output, you should see something like: Processing by UserseController#edit as HTML. That’s the controller (UsersController) and action (edit).

Finding a view file for a given page

• If in development, look at the server log. If it is too noisy, use tail -f log/development | grep Rendered to cut out the noise.
• If in development, add the rails_view_annotator gem to your Gemfile, and look at the DOM or HTML source. It should have HTML comments identifying the view partials responsible for their generated HTML.