why OmniAuth::Strategies::Facebook::NoAuthorizationCodeError is not handled in omniauth on_failure callback?

Question

I am using Omniauth for Rails 3.2.3 application.

I have configured the on_failure callback as show below.

OmniAuth.config.on_failure = Proc.new do |env|
  UsersController.action(:omniauth_failure).call(env)
end

This handles the error "OmniAuth::Strategies::CallbackError" but not "OmniAuth::Strategies::Facebook::NoAuthorizationCodeError".

How to handle this error?.Surly I can not use rescue_from as the error happens in Rack level.

Any ideas?

Thank you

Answer 1

Ensure that your Facebook Application is not running in "Sandbox Mode"

Answer 2

I've run into the same issue.

By my humble investigation it seems to be a bug in the strategy implemented in the omniauth-facebook gem (and, at a quick glance in several others). This is a nice write-up on exception handling in omniauth. It says that

... OmniAuth strategies [...], if they encounter a problem, call the method fail! and pass in a symbol describing the problem like :invalid_credentials and the exception they encountered. The fail! method ends up calling OmniAuth.config.on_failure and passing in the Rack environment (after doing a few other things like sticking the exception into the environment...

The same can be inferred from an example the original authors kindly provided. In the source it's not emphasized and I haven't found it in the wiki docs, either (but I may have overlooked).

Many strategies, including omniauth-facebook, currently raises the exception which we cannot catch at app level anymore.

Answer 3

@soundar: I wish that it worked this way, as advertised.

@fastcatch: As you pointed out, the strategies are not handling these failure cases correctly.

@Jon Day: I had to patch the Rack App for 'omniauth-facebook' (1.4.0) in order to get the reporting that I needed:

require 'newrelic_rpm'

module OmniAuth
  class Builder < ::Rack::Builder

    def call_with_error_handling(env)
      begin
        call_without_error_handling(env)
      rescue OmniAuth::Strategies::Facebook::NoAuthorizationCodeError => error
        # Do whatever you'd like when rescuing.. I wanted to report to NewRelic.
        NewRelic::Agent.notice_error(error, env)
        env
      end
    end

    alias_method_chain :call, :error_handling

  end
end

I'm not proud of this code, but it is one way to gain control over that exception ;).