Unable to override methods built with alias_method_chain

Rails
1

I am using this plugin and trying to extend it:

The plugin heavily modifies some the Rails routing (Rails 2.3.x in this
case, but that’s not important)

It usually follows this pattern:

module SubdomainRoutes
module UrlWriter
def self.included(base)
base.alias_method_chain :rewrite, :subdomains
end

def native_plugin_method
    ...a bunch of code
end

def rewrite_with_subdomains
   ...code
end

end
end

ActionController::UrlWriter.send :include, SubdomainRoutes::UrlWriter

In my own classes I am attempting to override some of these methods. So
i do this:

module CustomRouting

def native_plugin_method
     #successfully invoked
    ...a bunch of code
    super #will call method from SubdomainRoutes::UrlWriter
end

def rewrite_with_subdomains
   #method is never invoked
   ...code
   super
end

end

ActionController::UrlWriter.send :include, CustomRouting

The method created with alias_method_chain is never affected! My code
successfully overrides ‘native_plugin_method’, but it seems to do
nothing with rewrite_with_subdomains, even though everything is
identical.

Is there something about aliased methods that does not resolve in the
same way as standard methods?

2

On Tuesday, September 17, 2013 8:59:06 PM UTC+1, Ruby-Forum.com User
wrote:

aliasing pretty much creates a copy of a method - later attempts to
redefine the original method don’t affect the copy. For example

class Example
def foo
puts “foo”
end

alias_method :bar, :foo

def foo
puts “new foo”
end
end

Example.new.foo() #=> “new foo”
Example.new.bar() #=> “foo”

You’ll have to do your own alias method chaining when you include your
module (in newer versions of rails alias_method_chain has falled out of
favour)

Fred

3

Frederick C. wrote in post #1121711:

On Tuesday, September 17, 2013 8:59:06 PM UTC+1, Ruby-Forum.com User
wrote:

aliasing pretty much creates a copy of a method - later attempts to
redefine the original method don’t affect the copy. For example

class Example
def foo
puts “foo”
end

alias_method :bar, :foo

def foo
puts “new foo”
end
end

Example.new.foo() #=> “new foo”
Example.new.bar() #=> “foo”

You’ll have to do your own alias method chaining when you include your
module (in newer versions of rails alias_method_chain has falled out of
favour)

Fred

That’s exactly what it was! I had to re-alias the method names.

So the original plugin used alias_method_chain to alias :rewrite,
:rewrite_with_subdomain

I had to restructure my module like this:

module CustomRouting
def included(base)
base.send :alias_method, :rewrite, :rewrite_with_subdomains
end

def native_plugin_method
     #successfully invoked
    ...a bunch of code
    super #will call method from SubdomainRoutes::UrlWriter
end

def rewrite_with_subdomains
   #method is never invoked
   ...code
   super
end

end

And now my overloaded method is correctly invoked, and the ‘super’ call
works properly and invokes the previous alias.

This was really complicated. phew