Goalie

Goalie is a flexible dynamic error response renderer for Rails built on Rack and Rails Engines. It provides the same default error pages as Rails, but allows you to easily customize them with dynamic content. This means you can use your application layout, have different error pages for different subdomains, and do all sorts nice things.

Installation

gem install goalie

After you install it and add it to your Gemfile, you have to require it together with Rails' frameworks at the top of your config/application.rb file:

require 'goalie/rails'

This will remove Rails' default exception renderer middleware (ShowExceptions) and use Goalie's instead. Unless you have custom static pages in your public directory (which we plan to support later), this will be a drop-in replacement.

Customization

Controllers

The public (production) rescuing of errors is done by the PublicErrorsController found in Goalie's app/controllers directory. If you create a controller with the same name, it will automatically be used instead of Goalie's. All it needs to do is support the following actions:

• internal_server_error
• not_found
• unprocessable_entity
• conflict
• method_not_allowed
• not_implemented

If you don't actually need a separate action for each of these errors, you can redirect them to others, for example, with:

def unprocessable_entity
  render :action => 'internal_server_error'
end

Views

You can also customize only the views and use Goalie's default controller. All you need is to have inside app/views/public_errors views with the same names as the actions listed above.

Besides the standard stuff that Rails makes available to views, you will also have access to the following instance variables if you include the Goalie::ErrorDetails module:

• @request
• @exception
• @application_trace
• @framework_trace
• @full_trace

Be VERY careful when using this in production, as you could expose sensitive information inside the request and exception. Generally, you probably shouldn't use these variables at all. The only place it makes sense is to have a more detailed error screen for admins or other high-level users. By default these details are not available to the public errors views but can be made available if you override the PublicErrorsController and include the Goalie::ErrorDetails module.

Credit

Goalie copies a lot of code and ideas from:

• Rails' ShowExceptions middleware
• Rails' default error views
• Rails' exception_notification plugin

Which are mostly the work of Joshua Peek, with help from various contributors. We're highly indebted to them and thank them a lot for their work.

Contributions

Any form of feedback, patches, issues, and documentation are highly appreciated.

License

MIT license. Copyright 2010 Helder Ribeiro.