Kernel.load才能观察和处理我们为监控而编写的一些Ruby文件.然而,它似乎对这种恶作剧免疫.
很容易覆盖require和require_relative,但是如果我没记错的话,加载位于它们之下并且会阻塞实际的文件读取.
这就是为什么它似乎受到保护而不受覆盖：
Kernel.module_eval do
alias_method :original_require,:require
def require(filename)
require_result = original_require(filename)
puts "required #{filename}"
require_result
end
alias_method :original_load,:load
def load(filename,wrap=true)
load_result = original_load(filename,wrap)
puts "loaded #{filename}"
load_result
end
end
include Kernel
require 'open-uri'
puts 'done'
运行输出：
required uri/rfc2396_parser required uri/rfc3986_parser required uri/common required uri/common required uri/generic required uri/generic required uri/ftp required uri/generic required uri/http required uri/http required uri/https required uri/generic required uri/ldap required uri/ldap required uri/ldaps required uri/generic required uri/mailto required uri required stringio required date_core required date required time required open-uri done
我满足于只覆盖require和require_relative.但是,我很好奇负载是怎么回事.
后记：
看起来load不是由require或require_relative调用的. Mea culpa.好抓Matt.
这个问题类似于“How to override require in Ruby?”.
好读：
>“Ways to load code”
>“Ruby Require VS Load VS Include VS Extend”
>和Jörg’s“When monkey patching a method,can you call the overridden method from the new implementation?”的惊人答案
I also want to give some love to Module#prepend,which would allow you to simply use super instead of that ugly alias_method stuff,with the additional bonus that your modifications would actually show up in the ancestry chain and thus much easier to debug.
非常明智,值得使用.
> http://ruby-doc.org/core-2.2.2/Module.html#method-i-prepend
> http://ruby-doc.org/core-2.2.2/Module.html#method-i-prepend_features
> http://ruby-doc.org/core-2.2.2/Module.html#method-i-append_features
解决方法
module Kernel
old_require = method(:require)
define_method(:require) do |filename|
puts "require #{filename}"
old_require.call(filename)
end
old_require_relative = method(:require_relative)
define_method(:require_relative) do |filename|
puts "require_relative #{filename}"
old_require_relative.call(filename)
end
end
要么
module KernelExtensions
def require(filename)
puts "require #{filename}"
super
end
def require_relative(filename)
puts "require_relative #{filename}"
super
end
end
class Object
prepend KernelExtensions
end
使用第二个运行
module Kernel prepend KernelExtensions end
没有工作,但由于Object包含内核,使用类Object overriding似乎干净利落.