Rails中在当前请求范围内共享信息的机制是什么?
那些熟悉Asp.Net的人会知道,有一个HttpContext可用于在请求期间调用的所有实体。
Rails有什么相似之处吗?
最佳答案
使用around_filter
和Thread.current[]
,您可以轻松创建请求上下文/范围。请参见以下示例。
首先添加您的application_controller.rb
:
around_filter :request_context
def request_context
begin
RequestContext.begin_request
yield
ensure
RequestContext.end_request
end
end
现在将以下类添加到
lib/request_context.rb
class RequestContext
def self.instance
i = Thread.current[:request_context]
unless i
raise "No instance present. In script/rakefiles: use RequestContext.with_scope {}, " +
"in controller: ensure `around_filter :request_scope` is configured"
end
return i
end
# Allows the use of this scope from rake/scripts
# ContextScope.with_scope do |scope|
# # do something
# ...
# end
def self.with_scope
begin
begin_request
yield(instance)
ensure
end_request
end
end
def self.begin_request
raise "request_context already set" if Thread.current[:request_context]
Thread.current[:request_context] = RequestContext.new
end
def self.end_request
raise "request_context already nil" unless Thread.current[:request_context]
Thread.current[:request_context] = nil
end
# user part, add constructors/getters/setters here
def initialize
# you can setup stuff here, be aware that this
# is being called in _every_ request.
end
end
这很简单。您可以将数据存储在RequestContext.instance对象中,该对象将在每次请求后重新创建。
关于ruby-on-rails - Rails : share information within a Request scope,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/7323792/