Frontend Rescue

frontend_rescue provides a backend endpoint as a rack middleware for your frontend JavaScript application to send errors to when they’re caught.

This makes it easier to integrate your frontend stack traces to your backend analytics.

Installation

Add this line to your application's Gemfile:

gem 'frontend_rescue'

And then execute:

$ bundle

Or install it yourself as:

$ gem install frontend_rescue

Backend Usage

Rails

Use the frontend_rescue middleware :

Rails.application.configure do
  config.middleware.use FrontendRescue::Middleware
end

Options

status_code

By default, frontend_rescue will respond with a 500 (Server Error).

You can override this value with any HTTP status code you like :

config.middleware.use FrontendRescue::Middleware, status_code: 200

silent

By default, frontend_rescue will output the frontend error to the logs.

You can pass in silent: true, frontend errors are not logged. You will likely use this option when passing a block.

paths

By default, frontend_rescue will take post requests from /frontend-error. You can override this behavior by passing in an array of paths: ['/client/error']

exclude_user_agent

You might want to ignore certain user agents. You can exlude user agents with a Regexp: exclude_user_agent: /Googlebot/.

&block

You can pass in a block to frontend_rescue and it will be called and passed a FrontendRescue::Error and a Rack::Request :

config.middleware.use FrontendRescue::Middleware, status_code: 200, silent: true do |error, request|
  NewRelic::Agent.notice_error(error)
end

Sinatra

use FrontendRescue::Middleware

With the options described above.

Frontend Usage

Ideally you should catch all JavaScript errors and post them to your endpoint. Frontend frameworks like ember.js make this easy.

Ember example :

Ember.onerror = function(error) {
  Ember.$.ajax('/frontend-error', {
    type: 'POST',
    data: {
      name: 'My App',
      user_agent: navigator.userAgent,
      message: error.message,
      stack: error.stack,
      custom_params: {version: '1.0.0'}
    }
  });
};

Contributing

1. Fork it ( https://github.com/[my-github-username]/frontend_rescue/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request