Add npm support

README.md

@@ -208,6 +208,22 @@ folder under the result of running `rvm info` as the default SSH user (usualy
 it is already installed before enabling the bucket, otherwise you won't benefit
 from this plugin.
 
+#### npm
+
+```ruby
+Vagrant.configure("2") do |config|
+  config.vm.box = 'some-box-with-nodejs-installed'
+  config.cache.enable :npm
+end
+```
+
+Compatible with probably any type of linux guest distro, will hook into npm's
+cache directory under the result of running `npm config get cache` as
+the default SSH user (usually `vagrant`) on your guest.
+If you use
+[nvm](https://github.com/creationix/nvm) / [n](https://github.com/visionmedia/n)
+on the guest machine, make sure it is already installed before enabling
+the bucket, otherwise you won't benefit from this plugin.
 
 ##### APT-CACHER
 

lib/vagrant-cachier/bucket.rb

@@ -40,3 +40,4 @@ require_relative "bucket/pacman"
 require_relative "bucket/yum"
 require_relative "bucket/rvm"
 require_relative "bucket/apt_cacher"
+require_relative "bucket/npm"

lib/vagrant-cachier/bucket/npm.rb

@@ -0,0 +1,33 @@
+module VagrantPlugins
+  module Cachier
+    class Bucket
+      class Npm < Bucket
+        def self.capability
+          :npm_cache_dir
+        end
+
+        def install
+          machine = @env[:machine]
+          guest   = machine.guest
+
+          if guest.capability?(:npm_cache_dir)
+            guest_path = guest.capability(:npm_cache_dir)
+
+            @env[:cache_dirs] << guest_path
+
+            machine.communicate.tap do |comm|
+              comm.execute("mkdir -p /tmp/vagrant-cache/#{@name}")
+              unless comm.test("test -L #{guest_path}")
+                comm.execute("rm -rf #{guest_path}")
+                comm.execute("mkdir -p `dirname #{guest_path}`")
+                comm.execute("ln -s /tmp/vagrant-cache/#{@name} #{guest_path}")
+              end
+            end
+          else
+            @env[:ui].info I18n.t('vagrant_cachier.skipping_bucket', bucket: 'npm')
+          end
+        end
+      end
+    end
+  end
+end

lib/vagrant-cachier/cap/linux/npm_cache_dir.rb

@@ -0,0 +1,20 @@
+module VagrantPlugins
+  module Cachier
+    module Cap
+      module Linux
+        module NpmCacheDir
+          def self.npm_cache_dir(machine)
+            npm_cache_dir = nil
+            machine.communicate.tap do |comm|
+              return unless comm.test('which npm')
+              comm.execute 'npm config get cache' do |buffer, output|
+                npm_cache_dir = output.chomp if buffer == :stdout
+              end
+            end
+            return npm_cache_dir
+          end
+        end
+      end
+    end
+  end
+end

lib/vagrant-cachier/plugin.rb

@@ -31,6 +31,11 @@ module VagrantPlugins
         Cap::Linux::ChefFileCachePath
       end
 
+      guest_capability 'linux', 'npm_cache_dir' do
+        require_relative 'cap/linux/npm_cache_dir'
+        Cap::Linux::NpmCacheDir
+      end
+
       guest_capability 'debian', 'apt_cache_dir' do
         require_relative 'cap/debian/apt_cache_dir'
         Cap::Debian::AptCacheDir