Phoenix do not take into consideration my custom errorView

1. What headers do you have? Have you sent Accept: application/json?
2. Matching by template name is invalid. In case of 404, the template is the following: 404.json, not error.json.
3. The second parameter is not an exception, but assigns. The exception could be found in assigns.reason.

If you want generic handler for JSON format:

def render(<<_::binary-size(3)>> <> ".json" = template, assigns) do
  %{
    error: Phoenix.Controller.status_message_from_template(template),
    description: Exception.message(assigns.reason)
  }
end

but don’t show a message from all exceptions, as they may contain not public information

Thanks a lot @fuelen , so I get that “error_view.ex” is responsible from rendring theese errors, so what is the purpose of “fallback_controller.ex” ?

For example in my file “fallback_controller.ex” I have only :

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I’m not defining how Forbidden (403 status) will be handled, and If I try a forbidden action I get the correct error :

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action_fallback is about consolidating common error return values (of your business logic) and how they’re transformed to http responses (it’s about data).

MyAppWeb.ErrorView is a view, so it’s about transforming elixir data into json/html/whatever format your http response should be formatted in. This one specifically is about rendering responses for the various http error codes.

Wow, now that is some pattern-matching wizardry right there.