NoMethodError驗證 - RailsTutorial

Question

我在第二次跟隨Rails教程，我遇到了第一次嘗試時沒有的問題。

此錯誤發生在控制檯中。

我可以使用find_by_id，find_by_email方法，但不能驗證方法。

什麼寶石提供這種方法？ bycript？

這是錯誤消息。

irb(main):003:0> User.find_by_id("4") 
    User Load (0.3ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT ? [["id", 4], ["LIMIT", 1]] 
=> #<User id: 4, name: "Michael Hartl", email: "mhartl@example.com", created_at: "2016-07-12 16:08:19", updated_at: "2016-07-12 16:08:19", password_digest: "$2a$10$t4MhC/fb1gcnjygY1YPeaubxSBoY7tw3WNysg4TTGC1..."> 
irb(main):004:0> User.find_by_id("3") 
    User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT ? [["id", 3], ["LIMIT", 1]] 
=> nil 
irb(main):005:0> User.authenticate("oefheihfie") 
NoMethodError: undefined method `authenticate' for #<Class:0x007f7f770e1ed0> 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activerecord-5.0.0/lib/active_record/dynamic_matchers.rb:21:in `method_missing' 
    from (irb):5 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/railties-5.0.0/lib/rails/commands/console.rb:65:in `start' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/railties-5.0.0/lib/rails/commands/console_helper.rb:9:in `start' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:78:in `console' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/railties-5.0.0/lib/rails/commands/commands_tasks.rb:49:in `run_command!' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/railties-5.0.0/lib/rails/commands.rb:18:in `<top (required)>' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `require' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `block in require' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:259:in `load_dependency' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `require' 
    from /home/budi/gogo_app/bin/rails:9:in `<top (required)>' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:287:in `load' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:287:in `block in load' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:259:in `load_dependency' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:287:in `load' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/commands/rails.rb:6:in `call' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/command_wrapper.rb:38:in `call' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:191:in `block in serve' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:161:in `fork' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:161:in `serve' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:131:in `block in run' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:125:in `loop' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application.rb:125:in `run' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/spring-1.7.1/lib/spring/application/boot.rb:19:in `<top (required)>' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from /home/budi/.rbenv/versions/2.2.3/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require' 
    from -e:1:in `<main>'irb(main):006:0> ^C 

Answer 1

解決！

我忘了將實例賦值給一個變量。 分配後，我可以在該變量上使用authenticate methode。