Ruby Monkey Patch Class Method

All users of the monkey patched class see the same changes.

Ruby monkey patch class method.

Due to ruby s open classes you can redefine or add functionality to existing classes. Intro to monkey patching in ruby. Ruby has a very beautiful syntax and so it can be tempting to monkey patch a class to turn some ugly method call into something that is more readable. So the behavior of the class monkey is changed dynamically.

Every app with core patches feels a little bit different. You have to know where your monkey patches live. In the above class you are changing the behavior of the class method defined in the same program file. This can cause unintended side effects or breakage of programs.

Or perhaps you need to monkey patch a class you own. When you monkey patch core classes you add to the core ruby apis. There s no good reason to do this sort of patching because jruby marshals strings between java and ruby. In ruby the term monkey patch was misunderstood to mean any dynamic modification to a class and is often used as a synonym for dynamically modifying any class at runtime.

The above statement asserts that the ruby usage is incorrect but terms evolve and that s not always a bad thing. This is called a monkey patch. We are assigning a new method name patchfunc to the existing class method name monkeyfunc. So you have to have a way to quickly learn those changes when you jump into a new codebase.

The linking of a new method to the existing class method name happens at runtime. With that in mind let s look at a completely contrived example. 2 monkey patched java methods are only available in ruby code. These classes methods are implemented in c and there are certain abstractions sacrificed in order to make the implementation easier and more efficient.

For example you often see monkey patches that simply add a convenience method that has no side effect. Monkey patching changes the behavior of class methods. I mostly follow rails monkey patching convention. Patches go into lib core.

Unfortunately the scope of such changes is global. Motivated by the intent to patch existing third party code as a workaround to a bug or feature. In ruby a monkey patch mp is any dynamic modification to a class and is often used as a synonym for dynamically modifying any class add new or overwrite existing methods at runtime.