Ruby/Rails - 如何创建一个类并从控制器访问它
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Ruby/Rails - How to Create a Class and Access it from the Controller
提问by ChrisWesAllen
I've been trying to use a few different gems for displaying googlemaps within rails 3 and have had several problems.
我一直在尝试使用一些不同的 gem 在 rails 3 中显示谷歌地图，但遇到了几个问题。
Luckily I found this https://github.com/YouthTree/bhm-google-mapswhich is a helper and it seems to work for others.
幸运的是，我找到了这个https://github.com/YouthTree/bhm-google-maps，它是一个帮手，似乎对其他人有用。
I've installed it properly but in the readme https://github.com/YouthTree/bhm-google-maps/blob/master/README.mdit mentions creating a class for the object to display in the view.
我已经正确安装了它，但是在自述文件https://github.com/YouthTree/bhm-google-maps/blob/master/README.md 中它提到为要在视图中显示的对象创建一个类。
The example they gave was
他们举的例子是
class Location
attr_accessor :address, :lat, :lng
def initialize(address, lat, lng)
@address = address
@lat = lat
@lng = lng
end
def to_s; address.to_s; end
end
And then running
然后运行
<%= draw_map_of Location.new("My House", 12.345, 56.789) %>
in the view.
在视图中。
It seems simple enough but I haven't experienced the need of creating a class before in rails so I have some questions.
看起来很简单，但我之前没有经历过在 rails 中创建类的需要，所以我有一些问题。
Should I create a location.rb file and place the above code in it, but where should I place the file? (model folder, application folder????)
我应该创建一个 location.rb 文件并将上面的代码放入其中，但是我应该将文件放在哪里？（模型文件夹，应用程序文件夹？？？？）
Is there a way for me to create this class within my controller?
有没有办法在我的控制器中创建这个类？
Ideally I would like to manipulate the lat/lng values as variables and display a dynamic map.
理想情况下，我想将 lat/lng 值作为变量进行操作并显示动态地图。
回答by Dan Cheail
You should put location.rbwherever you feel it makes the most sense. Having it at app/models/location.rbwill ensure that it's automatically required when your app starts, but some people expect that classes in app/modelsare backed by ActiveRecord.
你应该把location.rb它放在你觉得最有意义的地方。随意使用它app/models/location.rb可以确保在您的应用程序启动时自动需要它，但有些人希望其中的类app/models由 ActiveRecord 支持。
You could also put it under lib/if you prefer.
lib/如果你愿意，你也可以把它放在下面。
To make it available to the app, you can include require statement in project initializers inside your config folder:
要使其可用于应用程序，您可以在 config 文件夹内的项目初始值设定项中包含 require 语句：
require "#{Rails.root}/lib/location.rb"
As for creating it inside your Controller - definitely! It's just another instance of a class:
至于在您的控制器中创建它 - 当然！它只是一个类的另一个实例：
def show
@location = Location.new("My House", 12.345, 56.789)
end
And then in your view:
然后在你看来：
<%= draw_map_of @location %>
Don't forget – beneath Rails is all the power and flexibility of pure Ruby, ready to be used. You're not only limited to what Rails gives you.
不要忘记 - 在 Rails 之下是纯 Ruby 的所有功能和灵活性，随时可以使用。您不仅限于 Rails 为您提供的功能。
