rescue_from is a very useful method in Rails. It lets us to catch exceptions and pass them to a callback or a block. A typical usecase is to handle ActiveRecord::RecordNotFound errors like in this example:
In the example above whenever an ActiveRecord::RecordNotFound raised in the scope of the FooController it will be caught and the notfound method will log the event than redirect to the notfound page with a message to display in the browser.
Since rescue_from works with a block too we can refactor the above as follows:
Another case when rescue_from comes handy is when we use cancan for authorization and we want to handle the authorization errors. We can do so by add the following to the application controller:
As you see in this case we display the exception message set by cancan.
If you want to use rescue_from from in a class which does not inherit from ActionController::Base you just need to mixin the ActiveSupport::Rescuable:
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