Ruby on Rails自定义迁移生成器 [英] Ruby on Rails Custom Migration Generator

问题描述

我正在创建一个与Active Record紧密集成的Rails创业板。宝石需要定义许多字段。例如：

  class User< ActiveRecord :: Base 
＃需要'avatar_identifier'，'avatar_extension'，'avatar_size'
 has_attached：avatar 
 end 
  

有可能有这样的东西：

  rails g模型用户名： string avatar：attached 
  

结果：

  create_table：users do | t | 
 t.string：name 
 t.string：avatar_identifier 
 t.string：avatar_extension 
 t.integer：avatar_size 
 end 
  
 
 
如果这是不可能的，  create_table：users do | t | 
 t.string：name 
 t.attached：avatar 
 end 
  
 
 
 <生成多个字段？谢谢！
解决方案
虽然Pravin确实指向了正确的方向，但我发现实现它并不简单。我做了以下操作，我在 config / initializers （名称不相关）中添加了一个文件，其中包含以下内容： 
 
 
  require'active_support'
 require'active_record'
 
 class YourApplication 
模块SchemaDefinitions 
 
模块ExtraMethod 
 def附件（* args）
选项= args.extract_options！ 
 args.each do | col | 
 column（＃{col} _identifier，：string，options）
 column（＃{col} _extension，：string，options）
 column（＃{col} _size ，：integer，options）
 end 
 end 
 end 
 
 def self.load！ 
 :: ActiveRecord :: ConnectionAdapters :: TableDefinition.class_eval {include YourApplication :: SchemaDefinitions :: ExtraMethod} 
结束
 $ b $结束
结束
 
 
 ActiveSupport.on_load：active_record do 
 YourApplication :: SchemaDefinitions.load！ 
 end 
  
然后您可以执行下列操作：
  rails g模型人名：字符串标题：字符串头像：附件
  
这将创建以下迁移： 
 
 
  def self.up 
 create_table：people do | t | 
 t.string：name 
 t.string：title 
 t.attachment：avatar 
 
 t.timestamps 
 end 
 end 
  
如果您然后运行迁移， rake db：migrate 它将创建以下 Person 模型： 
 
 
  ruby​​-1.9。 2-p0>人
 => Person（id：integer，name：string，title：string，avatar_identifier：string，avatar_extension：string，avatar_size：integer，created_at：datetime，updated_at：datetime）
  
希望这有助于!! 
 
I'm creating a Rails gem that integrates closely with Active Record. The gem requires a number of fields to be defined. For example:
class User < ActiveRecord::Base
  # requires 'avatar_identifier', 'avatar_extension', 'avatar_size'
  has_attached :avatar
end
Is it possible to have something like:
rails g model user name:string avatar:attached
Resulting in:
create_table :users do |t|
  t.string :name
  t.string :avatar_identifier
  t.string :avatar_extension
  t.integer :avatar_size
end
If this isn't possible, any way to make:
create_table :users do |t|
  t.string :name
  t.attached :avatar
end
Generate multiple fields? Thanks!
解决方案
While Pravin did point in the right direction, i found it was not straightforward to implement it. I did the following, i added a file in config/initializers (name is not relevant), containing the following:
require 'active_support'
require 'active_record'

class YourApplication
  module SchemaDefinitions

    module ExtraMethod
      def attachment(*args)
        options = args.extract_options!
        args.each do |col|
          column("#{col}_identifier", :string, options)
          column("#{col}_extension", :string, options)
          column("#{col}_size", :integer, options)
        end
      end
    end

    def self.load!
      ::ActiveRecord::ConnectionAdapters::TableDefinition.class_eval { include YourApplication::SchemaDefinitions::ExtraMethod }
    end

  end
end


ActiveSupport.on_load :active_record do
  YourApplication::SchemaDefinitions.load!
end
then you can just do something like:
rails g model Person name:string title:string avatar:attachment
which will create the following migration: 
def self.up
  create_table :people do |t|
    t.string :name
    t.string :title
    t.attachment :avatar

    t.timestamps
  end
end
If you then run the migration, rake db:migrate it will create the following Person model:
ruby-1.9.2-p0 > Person
 => Person(id: integer, name: string, title: string, avatar_identifier: string, avatar_extension: string, avatar_size: integer, created_at: datetime, updated_at: datetime) 
Hope this helps!!

                        
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