[英]Ruby/Rails: Prepend, append code to all methods
I wrote a small benchmarking Class for testing my code doing development. 我写了一个小的基准测试类来测试我的代码进行开发。 At the moment I have to add the Class to the beginning and end of every method. 目前我必须将Class添加到每个方法的开头和结尾。 Is it posible to prepend, append on the fly, so that I don't have to clutter my code? 是否可以预先添加,动态附加,以便我不必弄乱我的代码?
class ApplicationController
before_filter :init_perf
after_filter :write_perf_results_to_log!
def init_perf
@perf ||= Perf.new
end
def write_perf_results_to_log!
@perf.results
end
end
class Products < ApplicationsController
def foo
@perf.log(__methond__.to_s)
caculation = 5 *4
@perf.write!
end
def bar
@perf.log(__methond__.to_s)
caculation = 1 / 5
@perf.write!
end
end
This is the Perf class. 这是Perf类。 It is located in the services folder. 它位于services文件夹中。
class Perf
def initialize
@results = []
end
def log(note)
@start = Time.now
@note = note
end
def write!
if @results.find {|h| h[:note] == @note } # Update :sec method exists in results
@results.select { |h| h["note"] == @note; h[":sec"] = (Time.now - @start).round(3) }
else # Add new Hash to results
@results << { :note => @note, :sec => (Time.now - @start).round(3) }
end
end
def results
content = "
PERFORMANCE STATISTICS!
"
@results.each do |r|
content += r[:note] + " " + r[:sec].to_s + "
"
end
content += "
"
Rails.logger.info content
end
end
In general computing terms what you want to do is called code instrumentation . 在一般的计算术语中,您想要做的是称为代码检测 。 There are several ways to accomplish this, however here's one (crude) example using some metaprogramming: 有几种方法可以实现这一点,但是这是使用一些元编程的一个(粗略)示例:
First define a new method that we will use for injecting our instrumentation code: 首先定义一个新方法,我们将用它来注入我们的检测代码:
class ApplicationController
def self.instrument_methods(*methods)
methods.each { |m|
# Rename original method
self.send(:alias_method, "#{m}_orig", m)
# Redefine old method with instrumentation code added
define_method m do
puts "Perf log #{m}"
self.send "#{m}_orig"
puts "Perf write"
end
}
end
end
How to use it: 如何使用它:
class Product < ApplicationController
def foo
puts "Foo"
end
def bar
puts "Bar"
end
# This has to be called last, once the original methods are defined
instrument_methods :foo, :bar
end
Then: 然后:
p = Product.new
p.foo
p.bar
Will output: 将输出:
Perf log foo
Foo
Perf write
Perf log bar
Bar
Perf write
Here are some other ways to instrument ruby code and measure performance: 以下是一些其他方法来检测ruby代码并测量性能:
http://ruby-prof.rubyforge.org/ http://ruby-prof.rubyforge.org/
http://www.igvita.com/2009/06/13/profiling-ruby-with-googles-perftools/ http://www.igvita.com/2009/06/13/profiling-ruby-with-googles-perftools/
There is better solution. 有更好的解决方案。
class ApplicationController
def self.inherited(klass)
def klass.method_added(name)
return if @_not_new
@_not_new = true
original = "original #{name}"
alias_method original, name
define_method(name) do |*args, &block|
puts "==> called #{name} with args: #{args.inspect}"
result = send original, *args, &block
puts "<== result is #{result}"
result
end
@_not_new = false
end
end
end
class Product < ApplicationController
def meth(a1, a2)
a1 + a2
end
end
product = Product.new
puts product.meth(2,3)
And the result: 结果如下:
==> called meth with args: [2, 3]
<== result is 5
5
The source & explanation are here: http://pragprog.com/screencasts/v-dtrubyom/the-ruby-object-model-and-metaprogramming . 来源和解释如下: http : //pragprog.com/screencasts/v-dtrubyom/the-ruby-object-model-and-metaprogramming 。 I recommend to spend not a big money to get this course. 我建议不花很多钱来学习这门课程。
I'm the author of aspector gem. 我是aspector gem的作者。 Thanks to dimuch for mentioning it. 感谢dimuch提到它。
I've come up with a solution using aspector. 我想出了一个使用aspector的解决方案。 Here are the high level steps: 以下是高级步骤:
The full code can be found in this gist . 完整的代码可以在这个要点中找到。 Please feel free to let me know if you have questions or the solution doesn't do what you intend to. 如果您有任何疑问或解决方案没有达到您的目的,请随时告诉我。
class PerfAspect < Aspector::Base around options[:action_methods] do |proxy| @perf ||= Perf.new proxy.call @perf.results end around options[:other_methods], :method_arg => true do |method, proxy, *args, &block| @perf.log(method) result = proxy.call *args, &block @perf.write! result end end action_methods = [:action] other_methods = Products.instance_methods(false) - action_methods PerfAspect.apply(Products, :action_methods => action_methods, :other_methods => other_methods)
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