Ruby on rails RubyonRails：未定义的方法&x27；文摘'；轨道教程第10.1.1节

我目前正在学习Michael Hartl的Rails教程，我遇到了一个问题，我应该在我的用户模型中创建一个

create\u activation\u digest

操作，在注册时为每个用户创建并分配一个激活令牌和摘要

我首先使用以下方法重置迁移：

bundle exec rake db:migrate:reset

然后我使用以下方法将样本用户植入我的数据库：

bundle exec rake db:seed

但我收到一条错误消息，说明：

NoMethodError: undefined method `digest' for #<Class:0x007fb23ae0dcd0>

这是我在终端收到的错误消息：

0587343072:ruby_rails yuriramocan$ bundle exec rake db:seed --trace
** Invoke db:seed (first_time)
** Execute db:seed
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:abort_if_pending_migrations
rake aborted!
NoMethodError: undefined method `digest' for #<Class:0x007fb23ae0dcd0>
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/dynamic_matchers.rb:26:in `method_missing'
/Users/yuriramocan/Development/ruby_rails/app/models/user.rb:50:in `create_activation_digest'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:430:in `block in make_lambda'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:162:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:162:in `block in halting'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:502:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:502:in `block in call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:502:in `each'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:502:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:88:in `run_callbacks'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/callbacks.rb:306:in `_create_record'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/timestamp.rb:57:in `_create_record'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/persistence.rb:504:in `create_or_update'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/callbacks.rb:302:in `block in create_or_update'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:115:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:115:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:553:in `block (2 levels) in compile'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:503:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:503:in `call'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/callbacks.rb:88:in `run_callbacks'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/callbacks.rb:302:in `create_or_update'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/persistence.rb:142:in `save!'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/validations.rb:43:in `save!'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/attribute_methods/dirty.rb:29:in `save!'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/transactions.rb:291:in `block in save!'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/transactions.rb:351:in `block in with_transaction_returning_status'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/transaction.rb:184:in `within_new_transaction'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/transactions.rb:220:in `transaction'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/transactions.rb:348:in `with_transaction_returning_status'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/transactions.rb:291:in `save!'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/persistence.rb:51:in `create!'
/Users/yuriramocan/Development/ruby_rails/db/seeds.rb:1:in `<top (required)>'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:268:in `load'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:268:in `block in load'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:240:in `load_dependency'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:268:in `load'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/railties-4.2.3/lib/rails/engine.rb:547:in `load_seed'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/tasks/database_tasks.rb:250:in `load_seed'
/Users/yuriramocan/.rvm/gems/ruby-2.2.2/gems/activerecord-4.2.3/lib/active_record/railties/databases.rake:180:in `block (2 levels) in <top (required)>'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:240:in `call'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:240:in `block in execute'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:235:in `each'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:235:in `execute'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:179:in `block in invoke_with_call_chain'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/monitor.rb:211:in `mon_synchronize'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:172:in `invoke_with_call_chain'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/task.rb:165:in `invoke'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:150:in `invoke_task'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:106:in `block (2 levels) in top_level'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:106:in `each'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:106:in `block in top_level'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:115:in `run_with_threads'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:100:in `top_level'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:78:in `block in run'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:176:in `standard_exception_handling'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/lib/ruby/2.2.0/rake/application.rb:75:in `run'
/Users/yuriramocan/.rvm/rubies/ruby-2.2.2/bin/rake:33:in `<main>'
Tasks: TOP => db:seed

---

有人能帮我解决这个错误吗？在过去的两周里我一直很沮丧。谢谢。

您还没有定义类方法

摘要

，它应该看起来像

# Returns the hash digest of the given string.
  def User.digest(string)
    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                  BCrypt::Engine.cost
    BCrypt::Password.create(string, cost: cost)
  end

---

从Michael Hartl复制的代码

您可能错过了：

---

哇，是的！就这样。我完全错过了。非常感谢你@拉胡尔

User.create!(name:  "Example User",
             email: "example@railstutorial.org",
             password:              "foobar",
             password_confirmation: "foobar",
             admin: true,
             activated: true,
             activated_at: Time.zone.now)

99.times do |n|
  name  = Faker::Name.name
  email = "example-#{n+1}@railstutorial.org"
  password = "password"
  User.create!(name:  name,
               email: email,
               password:              password,
               password_confirmation: password,
               activated: true,
               activated_at: Time.zone.now)
end

# Returns the hash digest of the given string.
  def User.digest(string)
    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                  BCrypt::Engine.cost
    BCrypt::Password.create(string, cost: cost)
  end

def User.digest(string)
  cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                BCrypt::Engine.cost
  BCrypt::Password.create(string, cost: cost)
end