Class: Logging::Proxy

Inherits:
Object
  • Object
show all
Defined in:
lib/logging/proxy.rb

Overview

Defines a Proxy that will log all method calls on the proxied object. This class uses method_missing on a “blank slate” object to intercept all method calls. The method name being called and the arguments are all logged to the proxied object's logger instance. The log level and other settings for the proxied object are honored by the Proxy instance.

If you want, you can also supply your own method_missing code as a block to the constructor.

Proxy.new(object) do |name, *args, &block|
  # code to be executed before the proxied method
  result = @object.send(name, *args, &block)
  # code to be executed after the proxied method
  result   # <-- always return the result
end

The proxied object is available as the “@object” variable. The logger is available as the “@logger” variable.

Constant Summary collapse

KEEPERS =

:stopdoc:

%r/^__|^object_id$|^initialize$/

Instance Method Summary collapse

Constructor Details

#initialize(object, &block) ⇒ Proxy

Create a new proxy for the given object. If an optional block is given it will be called before the proxied method. This block will replace the method_missing implementation


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# File 'lib/logging/proxy.rb', line 35

def initialize( object, &block )
  Kernel.raise ArgumentError, "Cannot proxy nil" if nil.equal? object

  @object = object
  @leader = @object.is_a?(Class) ? "#{@object.name}." : "#{@object.class.name}#"
  @logger = Logging.logger[object]

  if block
    eigenclass = class << self; self; end
    eigenclass.__send__(:define_method, :method_missing, &block)
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object

All hail the magic of method missing. Here is where we are going to log the method call and then forward to the proxied object. The return value from the proxied object method call is passed back.


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# File 'lib/logging/proxy.rb', line 52

def method_missing( name, *args, &block )
  @logger << "#@leader#{name}(#{args.inspect[1..-2]})\n"
  @object.send(name, *args, &block)
end