Ruby on rails 在ruby实例中调用proc时,它的stac级别会太深
今天我遇到了一个关于ruby的非常有趣的问题。我有一个模块/轨道问题:Ruby on rails 在ruby实例中调用proc时,它的stac级别会太深,ruby-on-rails,ruby,proc,Ruby On Rails,Ruby,Proc,今天我遇到了一个关于ruby的非常有趣的问题。我有一个模块/轨道问题: module BreakCacheModule extend ActiveSupport::Concern module ClassMethods def breakable_cache_for(method_name, &block) method_name = method_name.to_sym set_breakable_cache_proc(method
module BreakCacheModule
extend ActiveSupport::Concern
module ClassMethods
def breakable_cache_for(method_name, &block)
method_name = method_name.to_sym
set_breakable_cache_proc(method_name, block)
define_breakable_cache_method(method_name)
end
def define_breakable_cache_method(method_name)
instance_eval(
"def #{method_name}
# here will be Rails.cache.fetch block around line below once I figure out this problem
@_break_cache_procs[#{method_name}].call # !!! this line will cause an issue
end"
)
end
def set_breakable_cache_proc(method_name, block)
@_break_cache_procs ||={}
@_break_cache_procs.merge!({method_name => block})
@_break_cache_procs
end
end
end
在我的模型中
class Client < ActiveRecord::Base
include BreakCacheModule
breakable_cache_for :all_client_ids do
Client.pluck :id
end
end
但当我这样做的时候:
Client.instance_variable_get("@_break_cache_procs")[:all_client_ids].call
#=> [1,2,3]
功能完全相同,唯一的区别是我不是从instance_eval调用proc
我错过了什么吗
我的ruby-2.0.0-p247和Rails 3.2.14
谢谢你的帮助
接受后更新 总而言之,我实际上从两个地方得到了这个错误:
"def #{method_name}
Rails.cache.fetch(#{method_name.to_s}) do # method_name should be in quotes
@_break_cache_procs[#{method_name}].call # missing colon ...look on answer
end
end"
所以代码应该是这样的
instance_eval(
"def #{method_name}
Rails.cache.fetch('#{method_name.to_s}') do
@_break_cache_procs[:#{method_name}].call
end
end"
)
传递给
instance\u eval
的字符串实际上是:
"def all_client_ids
@_break_cache_procs[all_client_ids].call
end"
您可能已经注意到问题:缺少一个冒号
这应该是正确的代码:
def define_breakable_cache_method(method_name)
instance_eval(
"def #{method_name}
# here will be Rails.cache.fetch block around line below once I figure out this problem
@_break_cache_procs[:#{method_name}].call # !!! this line will cause an issue
end"
)
end
嗨,是的,那只是我的输入错误,但不管有没有冒号,结果都是一样的
SystemStackError:stack level太深了
…thx真的吗?要调试这个问题,我认为您可以打印出传递给instance\u eval
的字符串。这样更容易发现问题。AAAAAA!我是个白痴,是的,你们是对的,这是因为结肠。它不起作用,因为之前我尝试它时,实际上从Rails.cache.fetch method\u name
中得到了相同的错误(我传递方法\u name时没有将其包装为撇号)
def define_breakable_cache_method(method_name)
instance_eval(
"def #{method_name}
# here will be Rails.cache.fetch block around line below once I figure out this problem
@_break_cache_procs[:#{method_name}].call # !!! this line will cause an issue
end"
)
end