Workaround in Twitter Omniauth using Omniauth v1+ (Rails)

user.rb

# In new Twitter Omniauth, you may encounter errors, first, please check the Omniauth env

auth = request.env["rack.auth"] #this is incorrect

auth = request.env["omniauth.auth"] #this is correct

# Another error I found is: 401 Unauthorized
# which is can be fixed in ROOT/config/initializer/omniauth.rb

# This is incorrect
Rails.application.config.middleware.use OmniAuth::Builder do
  provider :twitter, ENV['9S7MMaalIvDvFMOwwofF3w'], ENV['DQNsz3zzqvuFriHJYi8s2lm5WMzH4vFwWNkkdtUaNuA']
end

# This is correct
Rails.application.config.middleware.use OmniAuth::Builder do
  provider :twitter, '9S7MMaalIvDvFMOwwofF3w', 'DQNsz3zzqvuFriHJYi8s2lm5WMzH4vFwWNkkdtUaNuA'
end

# The last one I struggle is error that shows this 
# http://localhost:3000/auth/failure?message=invalid_response
# in your url (if you are not yet set route auth/failure elsewhere).
# I suspect this is because Omniauth surpress errors. So what you want to do is
# check your session controller (or wherever the auth/provider_name/callback is routed)

# notice this:
auth = request.env["omniauth.auth"]
# to get user ID, name, etc, you might use 
username = auth['user_info']['name']
# which is now incorrect and you can get username or else using:
username = auth['info']['name']
# and now everything works for me...