Go with site instead of store

Better fit for upload/download terminology.

lib/active_file/blob.rb

@@ -1,3 +1,5 @@
+require "active_file/site"
+
 # Schema: id, key, filename, content_type, metadata, byte_size, digest, created_at
 class ActiveFile::Blob < ActiveRecord::Base
   self.table_name = "active_file_blobs"
@@ -6,7 +8,7 @@ class ActiveFile::Blob < ActiveRecord::Base
   store :metadata, coder: JSON
 
   class_attribute :verifier, default: -> { Rails.application.message_verifier('ActiveFile') }
-  class_attribute :storage
+  class_attribute :site
 
   class << self
     def find_verified(signed_id)
@@ -31,7 +33,7 @@ class ActiveFile::Blob < ActiveRecord::Base
   end
 
   def delete
-    storage.delete token
+    site.delete token
   end
 
   def purge

lib/active_file/site.rb

@@ -1,4 +1,7 @@
-class ActiveFile::Store
+class ActiveFile::Site
+  def initialize
+  end
+
   def upload(key, data)
   end
 
@@ -23,4 +26,11 @@ class ActiveFile::Store
 
   def move(from_key:, to_key:)
   end
+
+
+  private
+    def normalize_key(key)
+      # disallow "." and ".." segments in the key
+      key.split(%r[/]).reject { |s| s == "." || s == ".." }
+    end
 end

lib/active_file/sites/disk_site.rb

@@ -0,0 +1,53 @@
+class ActiveFile::Sites::DiskSite < ActiveFile::Site
+  attr_reader :root
+
+  def initialize(root)
+    @root = root
+  end
+
+  def upload(key, data)
+    File.open(make_path_for(key), "wb") do |file|
+      while chunk = data.read(65536)
+        file.write(chunk)
+      end
+    end
+  end
+
+  def download(key)
+    if block_given?
+      open(key) do |file|
+        while data = file.read(65536)
+          yield data
+        end
+      end
+    else
+      open(key, &:read)
+    end
+  end
+
+  def delete(key)
+    File.delete(path_for(key))
+    true
+  end
+
+  def size(key)
+    File.size(path_for(key))
+  end
+
+  def checksum(key)
+    Digest::MD5.file(path_for(key)).hexdigest
+  end
+
+  private
+    def path_for(key)
+      File.join(root, folder_for(key), normalize(key))
+    end
+
+    def folder_for(key)
+      [key[0..1], key[2..3]].join("/")
+    end
+
+    def make_path_for(key)
+      path_for(key).tap { |path| FileUtils.mkdir_p File.dirname(path) }
+    end
+end