Ruby on rails 如何使用RoR和mongodb动态创建模型？

我正在尝试创建一个动态应用程序，通过元编程创建所需的任何类型的数据MVC我尝试了以下模型：

class DynamicRecord

    attr_accessor :name, :attributes

    def initialize(name, attributes = [])
        raise "Error: Constant #{name} already in namespace" if name.in? Object.constants
        a_new_class = Class.new(Object) do |clazz|
            include Mongoid::Document
            attributes.map do |attribute|
                field attribute[:name], type: attribute[:type]
            end
        end
        Object.const_set(name, a_new_class) 
    end
end

DynamicRecord.new('Person', [{name: :name, type: String}, {name: :email, type: String}])

person = Person.new(name: "Foo", email: "Foo@foo.com")
person.save

然后我得到这个错误：

Mongo::Error::OperationFailure: Invalid ns [mongodb_divcad_development.] (16257)
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/result.rb:256:in `validate!'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/insert.rb:60:in `block in execute_message'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/server/connection_pool.rb:107:in `with_connection'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/server.rb:242:in `with_connection'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/insert.rb:59:in `execute_message'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/write_command_enabled.rb:39:in `execute'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/collection.rb:365:in `block in insert_one'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/retryable.rb:112:in `write_with_retry'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/collection.rb:356:in `insert_one'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/query_cache.rb:182:in `insert_one_with_clear_cache'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:79:in `insert_as_root'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:27:in `block in insert'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:118:in `block (2 levels) in prepare_insert'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:373:in `_run__4510143668266298615__create__callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:80:in `run_callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/interceptable.rb:138:in `run_callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:117:in `block in prepare_insert'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:373:in `_run__4510143668266298615__save__callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active_support/callbacks.rb:80:in `run_callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/interceptable.rb:138:in `run_callbacks'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:116:in `prepare_insert'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/creatable.rb:23:in `insert'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/savable.rb:23:in `save'
    from (irb):70
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands/console.rb:90:in `start'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands/console.rb:9:in `start'
    from /home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands.rb:62:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

Mongo:：Error:：OperationFailure:无效的ns[mongodb_divcad_development.]（16257）
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/result.rb:256:in'validate！'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/insert.rb:60:“执行消息中的块”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/server/connection\u pool.rb:107:in“with\u connection”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/server.rb:242:in'with_connection'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/insert.rb:59:在“执行消息”中
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/operation/write/write_命令已启用。rb:39:在“执行”中
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/collection.rb:365:“插入块中插入一个”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/retryable.rb:112:in'write_with_retry'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongo-2.4.1/lib/mongo/collection.rb:356:in'insert_one'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/query\u cache.rb:182:“插入一个带有清除缓存的对象”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:79:in'insert_as_root'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:27:“插入中的块”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:118:prepare_insert中的“块（2层）”中
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active\u-support/callbacks.rb:373:in`“u-run”中的4510143668266298615“u-create\u-callbacks”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active\u support/callbacks.rb:80:in'run\u callbacks'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/interceptable.rb:138:in“run\u回调”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:117:“准备中的块插入”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active\u support/callbacks.rb:373:in`“u run”\u 4510143668266298615\u save\u callbacks”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/activesupport-4.0.2/lib/active\u support/callbacks.rb:80:in'run\u callbacks'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/interceptable.rb:138:in“run\u回调”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:116:in“prepare_insert”
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/createable.rb:23:in'insert'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/mongoid-5.2.0/lib/mongoid/persistable/savable.rb:23:in'save'
起始（irb）：70
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands/console.rb:90:in'start'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands/console.rb:9:in'start'
from/home/cassiano/.rvm/gems/ruby-2.3.3/gems/railties-4.0.2/lib/rails/commands.rb:62:in`'
从箱子/轨道：4:in“require”
从箱子/轨道：4:in`'

---

这可以做到吗？有一种更好的方法不必陷入实体属性值模型中？

我没有在本地尝试，这可能是一个愚蠢的答案……但我会改变

attributes.map to attributes.each看起来像是映射将返回一个数组并导致错误

还有。。。

---

查看mongoid的源代码。有一个名为add_field的方法，您可能可以使用。

我没有在本地尝试这个方法，这可能是一个愚蠢的答案……但我会改变

attributes.map to attributes.each看起来像是映射将返回一个数组并导致错误

还有。。。

---

查看mongoid的源代码。有一个名为add_field的方法，您可能可以利用它。

当您尝试使用动态模型时，Mongoid不知道名称空间。为了修复它，您应该将名称空间设置为

例如：

class DynamicCollection
  def self.create(collection, fields)
    klass = Class.new do
      include Mongoid::Document
      store_in collection: collection.downcase

      fields.each do |item|
        field item[:name], type: item[:type]
      end
    end

    Object.const_set(collection, klass) 
  end
end

fields = [
  {name: 'name', type: String},
  {name: 'email', type: String}
]

DynamicCollection.create('Demo', fields)

Demo.create!(name: 'SomeValue', email: 'SomeValue')

---

当您尝试使用动态模型时，Mongoid不知道名称空间。为了修复它，您应该将名称空间设置为

例如：

class DynamicCollection
  def self.create(collection, fields)
    klass = Class.new do
      include Mongoid::Document
      store_in collection: collection.downcase

      fields.each do |item|
        field item[:name], type: item[:type]
      end
    end

    Object.const_set(collection, klass) 
  end
end

fields = [
  {name: 'name', type: String},
  {name: 'email', type: String}
]

DynamicCollection.create('Demo', fields)

Demo.create!(name: 'SomeValue', email: 'SomeValue')

---

我尝试了以下方法：

a_new_class=class.new（Object）do include Mongoid:：Document include Mongoid:：Fields attributes.each do | attribute | field attribute[：name]，type:attribute[：type]add_field attribute[：name]end

相同错误…=/

.map

也可以工作。我尝试了以下方法：

a_new_class=class.new（Object）确实包括Mongoid:：Document include Mongoid:：Fields attributes.each do | attribute | field attribute[：name]，type:attribute[：type]添加_field attribute[：name]结束

相同错误…=/

.map

也可以工作