HOWTOs for Ruby on Rails and JavaScript

Strong params: Raise in development if unpermitted params are found

Rails 4:

config.action_controller.action_on_unpermitted_parameters enables logging or raising an exception if parameters that are not explicitly permitted are found. Set to :log or :raise to enable. The default value is :log in development and test environments, and false in all other environments.

Rails 3:

If you include the strong_params gem, see the Readme for handling unpermitted keys.

guides.rubyonrails.org

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Detect mobile or touch devices on both server and client

Although it's tempting flirt with detecting mobile/touch devices with CSS media queries or Javascript feature detection alone, this approach will be painful when heavily customizing a feature beyond just tweaking the looks. Eventually you will want want the same detection logic to be available on both server and client side.

This card shows how to get a Ruby method touch_device? for your Rails views and a method TouchDevice.isPresent() for your Javascripts.

Note that we are detecting touch devices by grepping the user agent, and the ke...

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Speed up better_errors

If you use the Better Errors gem, you will sometimes notice that it can be very slow. This is because it sometimes renders a huge amount of data that will actually be hard to render for your browser.

You can significantly improve performance by adding this to config/initializers/better_errors:

if defined?(BetterErrors) && Rails.env.development?
  module BetterErrorsHugeInspectWarning
    def inspect_value(obj)
      inspected = obj.inspect
      if inspected.size > 20_000
        inspec...

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whenever: Make runner commands use bundle exec

In whenever you can schedule Ruby code directly like so:

every 1.day, :at => '4:30 am' do
  runner "MyModel.task_to_run_at_four_thirty_in_the_morning"
end

Combined with the best practice to hide background tasks behind a single static methods you can test, this is probably preferable to defining additional Rake tasks.

Unfortunately when whenever register a runner command, it doesn't use bundle exec in the resulting crontab. This gets you errors like this:

`gem_original_require': no suc...

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Disable text-transforms in Selenium tests

Using text-transform: uppercase - especially on form labels - can cause you serious headaches in Selenium tests. Sometimes the web driver will see the uppercase text, sometimes it won't, and umlauts will be a problem as well.

Simply disable it in tests, by

adding a body class for tests
```
%body{'data-environment' => Rails.env}
```

overriding the transforms

[data-environment="test"] *
  text-transform: none !important

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faviconit.com: Super-simple favicon generator

Eduardo Russo was tired of complex favicon creation and created his own favicon generator. It's really easy and allows a lot of image editing before rendering the favicons, in all needed sizes, formats and with the HTML needed to include them!

In Rails applications with Haml:

put all the favicon files into /public
store the HTML to app/views/layouts/_favicon.html
add = render 'layouts/favicon' to <head> in your application layout(s)

... and you're all...

faviconit.com

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How to: Run webpack dev server with vcap.me

If your Rails application is using Webpack you need to serve assets on the same host as you application runs, otherwise you will see the following errors in your browser console:

[WDS] Disconnected!
Invalid Host header

So if you are using awesome.vcap.me:3000 you need to start the webpack-dev-server with a different host than localhost (0.0.0.0):

bin/webpack-dev-server --host awesome.vcap.me

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