No route matches {:action=>"show", :controller=>"members", :id=>nil} - ruby-on-rails

Question

I set up twitter login system and got the error message above around the codes
redirect_to member_path(session[:user_id]), :notice => "#{auth["info"]["name"]}さんの#{auth["provider"]}アカウントと接続しました。"
in the def callback of the sessions_controller.rb. I wonder why this happened because it never happened when I set up facebook login with omniauth gem.Could you tell me why this occurred and how to solve this?
I checked some elements. A new user was created through twitter login. And I could get "session". But couldn't acquire session[:user_id].
☆member.rb
def self.create_with_omniauth(auth)
create! do |member|
member.provider = auth["provider"]
member.uid = auth["uid"]
member.mail = auth["mail"]
member.image = auth["info"]["image"]
if member.provider == "facebook"
member.name = auth["info"]["name"]
else
member.name = auth["info"]["nickname"]
end
end
end
☆sessions_controller
def callback
#omniauth.auth環境変数を取得
auth = request.env["omniauth.auth"]
#Userモデルを検索
member = Member.find_by_provider_and_uid(auth["provider"], auth["uid"])
if member
# 既存のユーザ情報があった場合ルートに遷移させます
session[:user_id] = member.id
redirect_to member_path(session[:user_id]), :notice => "ログインしました。"
else
# Userモデルに:providerと:uidが無い場合（外部認証していない）、保存してからルートへ遷移させる
Member.create_with_omniauth(auth)
redirect_to member_path(session[:user_id]), :notice => "#{auth["info"]["name"]}さんの#{auth["provider"]}アカウントと接続しました。"
end
end

Answer 1

Your problem is that you try to build a member route which requires id for member. Other words Rails should build routes like /members/:id where id MUST be a number. When you pass session[:id] (which is nil!) to the route helper member_path you get an error.
What to do?
1) (if you use a gem for authentication, for example devise) you can pass to the route helper current_user: memeber_path(current_user)
2) if you have own method which authenticate user you can set session[:user_id] youself.
I suppose that the problem is in else-block. So you can define session[user_id] after a new Member is created. I hope that method Member.create_with_omniauth(auth) return a new member - it means that you need take its id
if member
# 既存のユーザ情報があった場合ルートに遷移させます
session[:user_id] = member.id
redirect_to member_path(session[:user_id]), :notice => "ログインしました。"
else
# Userモデルに:providerと:uidが無い場合（外部認証していない）、保存してからルートへ遷移させる
session[:user_id] = Member.create_with_omniauth(auth).id # <--- UPDATED PART IS HERE
redirect_to member_path(session[:user_id]), :notice => "#{auth["info"]["name"]}さんの#{auth["provider"]}アカウントと接続しました。"
end
PS
And anyway you can avoid to render/redirect to this route if session[:user_id] is nil
redirect_to member_path(session[:user_id]) if session[:user_id]