Ruby on Rails中的语法错误

时间：2012-12-17 13:59:13

标签： ruby-on-rails ruby-on-rails-3 ruby-on-rails-3.2

您好我是ruby on rails平台的初学者，我正在阅读railstutorial.org书。我的Micopost1.rb文件内容是

class Micropost1 < ActiveRecord::Base
  attr accessible :content, :user_id

belongs_to :user

validates :content, :length => { :maximum => 140 }

end

当我运行rails.console命令时，当我输入控制台时会打开一个控制台 第一个user.microposts，然后我得到以下错误日志，

SyntaxError: /home/ritesh/projects/demo/app/models/micropost1.rb:2: syntax error, unexpected tIDENTIFIER, expecting kEND
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:469:in `load'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:469:in `load_file'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:639:in `new_constants_in'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:468:in `load_file'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:353:in `require_or_load'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:502:in `load_missing_constant'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:192:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `each'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:514:in `load_missing_constant'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:192:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `each'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:219:in `constantize'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:218:in `each'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:218:in `constantize'
... 10 levels...
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:44:in `__send__'
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:44:in `load_target'
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:87:in `method_missing'
    from /usr/lib/ruby/1.8/irb.rb:310:in `output_value'
    from /usr/lib/ruby/1.8/irb.rb:159:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:271:in `signal_status'
    from /usr/lib/ruby/1.8/irb.rb:155:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:154:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:71:in `start'
    from /usr/lib/ruby/1.8/irb.rb:70:in `catch'
    from /usr/lib/ruby/1.8/irb.rb:70:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands/console.rb:47:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands/console.rb:8:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands.rb:41
    from script/rails:6:in `require'
    from script/rails:6irb(main):004:0> first_user.micropost1s
NoMethodError: undefined method `accessible' for #<Class:0xb6651934>
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/dynamic_matchers.rb:50:in `method_missing'
    from /home/ritesh/projects/demo/app/models/micropost1.rb:2
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:469:in `load'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:469:in `load_file'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:639:in `new_constants_in'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:468:in `load_file'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:353:in `require_or_load'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:502:in `load_missing_constant'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:192:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `each'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:514:in `load_missing_constant'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:192:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `each'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:190:in `const_missing'
    from /var/lib/gems/1.8/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:219:in `constantize'
... 12 levels...
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:44:in `__send__'
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:44:in `load_target'
    from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/associations/collection_proxy.rb:87:in `method_missing'
    from /usr/lib/ruby/1.8/irb.rb:310:in `output_value'
    from /usr/lib/ruby/1.8/irb.rb:159:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:271:in `signal_status'
    from /usr/lib/ruby/1.8/irb.rb:155:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:154:in `eval_input'
    from /usr/lib/ruby/1.8/irb.rb:71:in `start'
    from /usr/lib/ruby/1.8/irb.rb:70:in `catch'
    from /usr/lib/ruby/1.8/irb.rb:70:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands/console.rb:47:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands/console.rb:8:in `start'
    from /var/lib/gems/1.8/gems/railties-3.2.9/lib/rails/commands.rb:41
    from script/rails:6:in `require'

我没有得到我错的地方有两个模型1是User，第二个是Micropost1 首先，我运行此命令来分配变量first_user first_user = User.first 请指出我错误的地方。

3 个答案:

答案 0 :(得分：3)

attr accessible应该是一个词：attr_accessible

如果你向下看堆栈跟踪，你会看到以下错误：

NoMethodError: undefined method `accessible' for #<Class:0xb6651934>
  from /var/lib/gems/1.8/gems/activerecord-3.2.9/lib/active_record/dynamic_matchers.rb:50:in `method_missing'
  from /home/ritesh/projects/demo/app/models/micropost1.rb:2

此错误表示在micropost1.rb文件的第2行，有一个不存在的方法被调用。

答案 1 :(得分：2)

试试这个...... 

class Micropost1 < ActiveRecord::Base
  attr_accessible :content, :user_id

  belongs_to :user

  validates :content, :length => { :maximum => 140 }

end

你在模型中写的是'attr accessible'， 就像上面写的那样'attr_accessible'......

答案 2 :(得分：0)

你应该做一些调查，假装你是夏洛克福尔摩斯！

线索1 

SyntaxError: /home/ritesh/projects/demo/app/models/micropost1.rb:2: syntax error, unexpected tIDENTIFIER, expecting kEND

你知道你有什么样的错误，语法错误。你拼错了一些东西。

线索2

如果仔细观察，可以看到我们还有其他线索，错误告诉您它在模型中micropost1.rb:2而:2表示它位于代码的第二行。

线索3

哦，你知道错误在哪里以及它是什么样的错误。但unexpected tIDENTIFIER, expecting kEND是什么意思？谷歌是你的沃森。他给你6 630个不同的答案。

结案

您发现自己在模型中写的是'attr accessible'，而应该是'attr_accessible'。

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