Merge branch 'schema-helper' of https://github.com/dasch/paperclip

README.md

@@ -80,17 +80,13 @@ In your migrations:
 
     class AddAvatarColumnsToUser < ActiveRecord::Migration
       def self.up
-        add_column :users, :avatar_file_name,    :string
-        add_column :users, :avatar_content_type, :string
-        add_column :users, :avatar_file_size,    :integer
-        add_column :users, :avatar_updated_at,   :datetime
+        change_table :users do |t|
+          t.has_attached_file :avatar
+        end
       end
 
       def self.down
-        remove_column :users, :avatar_file_name
-        remove_column :users, :avatar_content_type
-        remove_column :users, :avatar_file_size
-        remove_column :users, :avatar_updated_at
+        drop_attached_file :users, :avatar
       end
     end
 

lib/paperclip/railtie.rb

 require 'paperclip'
+require 'paperclip/schema'
 
 module Paperclip
   if defined? Rails::Railtie
@@ -21,6 +22,10 @@ module Paperclip
       File.send(:include, Paperclip::Upfile)
 
       Paperclip.options[:logger] = defined?(ActiveRecord) ? ActiveRecord::Base.logger : Rails.logger
+
+      ActiveRecord::ConnectionAdapters::AbstractAdapter.send(:include, Paperclip::Schema)
+      ActiveRecord::ConnectionAdapters::Table.send(:include, Paperclip::Schema)
+      ActiveRecord::ConnectionAdapters::TableDefinition.send(:include, Paperclip::Schema)
     end
   end
 end

lib/paperclip/schema.rb

+module Paperclip
+  # Provides two helpers that can be used in migrations.
+  #
+  # In order to use this module, the target class should implement a
+  # +column+ method that takes the column name and type, both as symbols,
+  # as well as a +remove_column+ method that takes a table and column name,
+  # also both symbols.
+  module Schema
+    @@columns = {:file_name    => :string,
+                 :content_type => :string,
+                 :file_size    => :integer,
+                 :updated_at   => :datetime}
+
+    def has_attached_file(attachment_name)
+      with_columns_for(attachment_name) do |column_name, column_type|
+        column(column_name, column_type)
+      end
+    end
+
+    def drop_attached_file(table_name, attachment_name)
+      with_columns_for(attachment_name) do |column_name, column_type|
+        remove_column(table_name, column_name)
+      end
+    end
+
+    protected
+
+    def with_columns_for(attachment_name)
+      @@columns.each do |suffix, column_type|
+        column_name = full_column_name(attachment_name, suffix)
+        yield column_name, column_type
+      end
+    end
+
+    def full_column_name(attachment_name, column_name)
+      "#{attachment_name}_#{column_name}".to_sym
+    end
+  end
+end

test/schema_test.rb

+
+require 'test/helper'
+
+class MockSchema
+  include Paperclip::Schema
+
+  def initialize(table_name = nil)
+    @table_name = table_name
+    @columns = {}
+    @deleted_columns = []
+  end
+
+  def column(name, type)
+    @columns[name] = type
+  end
+
+  def remove_column(table_name, column_name)
+    return if @table_name && @table_name != table_name
+    @columns.delete(column_name)
+    @deleted_columns.push(column_name)
+  end
+
+  def has_column?(column_name)
+    @columns.key?(column_name)
+  end
+
+  def deleted_column?(column_name)
+    @deleted_columns.include?(column_name)
+  end
+
+  def type_of(column_name)
+    @columns[column_name]
+  end
+end
+
+class SchemaTest < Test::Unit::TestCase
+  context "Migrating up" do
+    setup do
+      @schema = MockSchema.new
+      @schema.has_attached_file :avatar
+    end
+
+    should "create the file_name column" do
+      assert @schema.has_column?(:avatar_file_name)
+    end
+
+    should "create the content_type column" do
+      assert @schema.has_column?(:avatar_content_type)
+    end
+
+    should "create the file_size column" do
+      assert @schema.has_column?(:avatar_file_size)
+    end
+
+    should "create the updated_at column" do
+      assert @schema.has_column?(:avatar_updated_at)
+    end
+
+    should "make the file_name column a string" do
+      assert_equal :string, @schema.type_of(:avatar_file_name)
+    end
+
+    should "make the content_type column a string" do
+      assert_equal :string, @schema.type_of(:avatar_content_type)
+    end
+
+    should "make the file_size column an integer" do
+      assert_equal :integer, @schema.type_of(:avatar_file_size)
+    end
+
+    should "make the updated_at column a datetime" do
+      assert_equal :datetime, @schema.type_of(:avatar_updated_at)
+    end
+  end
+
+  context "Migrating down" do
+    setup do
+      @schema = MockSchema.new(:users)
+      @schema.drop_attached_file :users, :avatar
+    end
+
+    should "remove the file_name column" do
+      assert @schema.deleted_column?(:avatar_file_name)
+    end
+
+    should "remove the content_type column" do
+      assert @schema.deleted_column?(:avatar_content_type)
+    end
+
+    should "remove the file_size column" do
+      assert @schema.deleted_column?(:avatar_file_size)
+    end
+
+    should "remove the updated_at column" do
+      assert @schema.deleted_column?(:avatar_updated_at)
+    end
+  end
+end