Ruby using namespace/module

Question

For example:

require 'net/http'
uri = URI('http://example.com/some_path?query=string')

Net::HTTP.start(uri.host, uri.port) do |http|
  request = Net::HTTP::Get.new uri

  response = http.request request # Net::HTTPResponse object
end

What is the correct/rubist way to get rid of Net::HTTP ? i.e. HTTP::Get.new() or just Get.new()

Solution 1

If you want to shorten these, you can just import that namespace:

Net::HTTP.start(...)

include Net
# HTTP.start(...)

Be careful when you import aggressively as it might cause conflict within your class if you get carried away.

An alternative is to create aliases:

HTTP = Net::HTTP
Get = Net::HTTP::Get

The "correct" way is to just spell it out and not get too flustered by that. A typical Ruby program will bury this sort of low-level behavior beneath an abstraction layer so it's rarely a big deal.

Solution 2

I hope this example will clarify things.

module Foo
  def foo
    "foo"
  end
end

class Bar
  include Foo

  def bar
    "bar"
  end
end

Bar.new.foo # foo
Bar.new.bar # bar

class Baz
  extend Foo

  self.def baz
    "baz"
  end
end

Baz.foo # foo
Baz.baz # baz

Make sure you know what you are doing when you use import or extend. You could end up overriding a method that you might not want to override.

Solution 3

require 'net/http'
uri = URI('http://example.com/some_path?query=string')

httpns = Net::HTTP

def get(uri)
   httpns::Get.new uri
end

http.start(uri.host, uri.port) do |http|
  request = get uri

  response = http.request request # Net::HTTPResponse object
end

in your class.

Comments

[w00d]

I can't include Net::HTTP, it throws error: TypeError: wrong argument type Class (expected Module)

[tadman]

Ah, I should remove that then. include only works on modules, but it's hard to tell how these things are structured by just looking at use cases. Aliases might work better. In any case, typing Net::HTTP is something that makes it abundantly clear what you're doing, and hiding that is usually a bad idea.