Add attachments

README.md

@@ -6,26 +6,11 @@
 
 ```ruby
 class Person < ApplicationRecord
-  has_one :avatar
-end
-
-class Avatar < ApplicationRecord
-  belongs_to :person
-  belongs_to :image, class_name: 'ActiveVault::Blob'
-
-  has_file :image
+  has_file :avatar
 end
 
 avatar.image.url(expires_in: 5.minutes)
 
-
-class ActiveVault::DownloadsController < ActionController::Base
-  def show
-    head :ok, ActiveVault::Blob.locate(params[:id]).download_headers
-  end
-end
-
-
 class AvatarsController < ApplicationController
   def create
     # @avatar = Avatar.create \

lib/active_vault/attachment.rb

@@ -0,0 +1,27 @@
+require "active_vault/blob"
+require "global_id"
+require "active_support/core_ext/module/delegation"
+
+# Schema: id, record_gid, blob_id, created_at
+class ActiveVault::Attachment < ActiveRecord::Base
+  self.table_name = "active_vault_attachments"
+
+  belongs_to :blob, class_name: "ActiveVault::Blob"
+
+  delegate_missing_to :blob
+
+  def record
+    @record ||= GlobalID::Locator.locate(record_gid)
+  end
+
+  def record=(record)
+    @record = record
+    self.record_gid = record&.to_gid
+  end
+
+  def purge
+    blob.purge
+    destroy
+    record.public_send "#{name}=", nil
+  end
+end

lib/active_vault/attachments.rb

@@ -0,0 +1,30 @@
+require "active_vault/attachment"
+require "action_dispatch/http/upload"
+
+module ActiveVault::Attachments
+  def has_file(name)
+    define_method(name) do
+      (@active_vault_attachments ||= {})[name] ||=
+        ActiveVault::Attachment.find_by(record_gid: to_gid.to_s, name: name)&.tap { |a| a.record = self }
+    end
+
+    define_method(:"#{name}=") do |attachable|
+      case attachable
+      when ActiveVault::Blob
+        blob = attachable
+      when ActionDispatch::Http::UploadedFile
+        blob = ActiveVault::Blob.create_after_upload! \
+          io: attachable.open,
+          filename: attachable.original_filename,
+          content_type: attachable.content_type
+      when Hash
+        blob = ActiveVault::Blob.create_after_upload!(attachable)
+      when NilClass
+        blob = nil
+      end
+
+      (@active_vault_attachments ||= {})[name] = blob ?
+        ActiveVault::Attachment.create!(record_gid: to_gid.to_s, name: name, blob: blob)&.tap { |a| a.record = self } : nil
+    end
+  end
+end

lib/active_vault/migration.rb

@@ -1,15 +1,28 @@
-class ActiveVault::CreateBlobs < ActiveRecord::Migration[5.1]
+class ActiveVault::CreateTables < ActiveRecord::Migration[5.1]
   def change
-      t.string :key
-      t.string :filename
-      t.string :content_type
-      t.text :metadata
     create_table :active_vault_blobs do |t|
+      t.string  :key
+      t.string  :filename
+      t.string  :content_type
+      t.text    :metadata
       t.integer :byte_size
-      t.string :checksum
-      t.time :created_at
+      t.string  :checksum
+      t.time    :created_at
 
       t.index [ :key ], unique: true
     end
+
+    create_table :active_vault_attachments do |t|
+      t.string  :name
+      t.string  :record_gid
+      t.integer :blob_id
+
+      t.time :created_at
+
+      t.index :record_gid
+      t.index :blob_id
+      t.index [ :record_gid, :name ]
+      t.index [ :record_gid, :blob_id ], unique: true
+    end
   end
 end

lib/active_vault/railtie.rb

@@ -15,5 +15,13 @@ module ActiveVault
         end
       end
     end
+
+    initializer "action_file.attachments" do
+      require "active_vault/attachments"
+
+      ActiveSupport.on_load(:active_record) do
+        extend ActiveVault::Attachments
+      end
+    end
   end
 end

test/attachments_test.rb

@@ -0,0 +1,27 @@
+require "test_helper"
+require "database/setup"
+require "active_vault/blob"
+
+# ActiveRecord::Base.logger = Logger.new(STDOUT)
+
+class User < ActiveRecord::Base
+  has_file :avatar
+end
+
+class ActiveVault::AttachmentsTest < ActiveSupport::TestCase
+  setup { @user = User.create!(name: "DHH") }
+
+  test "create attachment from existing blob" do
+    @user.avatar = create_blob filename: "funky.jpg"
+    assert_equal "funky.jpg", @user.avatar.filename.to_s
+  end
+
+  test "purge attached blob" do
+    @user.avatar = create_blob filename: "funky.jpg"
+    avatar_key = @user.avatar.key
+
+    @user.avatar.purge
+    assert_nil @user.avatar
+    assert_not ActiveVault::Blob.site.exist?(avatar_key)
+  end
+end

test/database/create_users_migration.rb

@@ -0,0 +1,7 @@
+class ActiveVault::CreateUsers < ActiveRecord::Migration[5.1]
+  def change
+    create_table :users do |t|
+      t.string :name
+    end
+  end
+end

test/database/setup.rb

@@ -1,4 +1,6 @@
 require "active_vault/migration"
+require_relative "create_users_migration"
 
 ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
-ActiveVault::CreateBlobs.migrate(:up)
+ActiveVault::CreateTables.migrate(:up)
+ActiveVault::CreateUsers.migrate(:up)

test/test_helper.rb

@@ -17,4 +17,12 @@ class ActiveSupport::TestCase
     def create_blob(data: "Hello world!", filename: "hello.txt", content_type: "text/plain")
       ActiveVault::Blob.create_after_upload! io: StringIO.new(data), filename: filename, content_type: content_type
     end
-end
+end
+
+
+require "active_vault/attachments"
+ActiveRecord::Base.send :extend, ActiveVault::Attachments
+
+require "global_id"
+GlobalID.app = "ActiveVaultExampleApp"
+ActiveRecord::Base.send :include, GlobalID::Identification