added post voting

app/models/comment.rb

@@ -1,6 +1,4 @@
 class Comment < ActiveRecord::Base  
-  class VotingError < Exception ; end
-  
   validates_format_of :body, :with => /\S/, :message => 'has no content'
   belongs_to :post
   belongs_to :creator, :class_name => "User"
@@ -35,7 +33,7 @@ class Comment < ActiveRecord::Base
       
       votes.create(:user_id => user.id)
     else
-      raise VotingError.new("You have already voted for this comment")
+      raise CommentVote::Error.new("You have already voted for this comment")
     end
   end
 end

app/models/comment_vote.rb

@@ -1,4 +1,6 @@
 class CommentVote < ActiveRecord::Base
+  class Error < Exception ; end
+
   belongs_to :comment
   belongs_to :user
   

app/models/post.rb

@@ -12,6 +12,7 @@ class Post < ActiveRecord::Base
   has_one :unapproval, :dependent => :destroy
   has_one :upload, :dependent => :destroy
   has_many :versions, :class_name => "PostVersion", :dependent => :destroy  
+  has_many :votes, :class_name => "PostVote", :dependent => :destroy
   attr_accessible :source, :rating, :tag_string, :old_tag_string
   
   module FileMethods
@@ -140,7 +141,7 @@ class Post < ActiveRecord::Base
       self.source = version.source
       self.rating = version.rating
       self.tag_string = version.tag_string
-      save
+      save!
     end
   end
   
@@ -473,6 +474,26 @@ class Post < ActiveRecord::Base
     end
   end
   
+  module VoteMethods
+    def can_be_voted_by?(user)
+      !votes.exists?(["user_id = ?", user.id])
+    end
+
+    def vote!(user, is_positive)
+      if can_be_voted_by?(user)
+        if is_positive
+          increment!(:score)
+        else
+          decrement!(:score)
+        end
+
+        votes.create(:user_id => user.id)
+      else
+        raise PostVote::Error.new("You have already voted for this comment")
+      end
+    end
+  end
+  
   include FileMethods
   include ImageMethods
   include ModerationMethods
@@ -483,6 +504,7 @@ class Post < ActiveRecord::Base
   include UploaderMethods
   include PoolMethods
   extend SearchMethods
+  include VoteMethods
   
   def reload(options = nil)
     super

app/models/post_vote.rb

@@ -0,0 +1,5 @@
+class PostVote < ActiveRecord::Base
+  class Error < Exception ; end
+  
+  belongs_to :post
+end

app/models/user.rb

@@ -14,10 +14,6 @@ class User < ActiveRecord::Base
   after_save :update_cache
   scope :named, lambda {|name| where(["lower(name) = ?", name])}  
   
-  def can_update?(object, foreign_key = :user_id)
-    is_moderator? || is_admin? || object.__send__(foreign_key) == id
-  end
-
   module NameMethods
     module ClassMethods
       def find_name(user_id)
@@ -100,5 +96,9 @@ class User < ActiveRecord::Base
   include PasswordMethods
   extend AuthenticationMethods
   include FavoriteMethods
+
+  def can_update?(object, foreign_key = :user_id)
+    is_moderator? || is_admin? || object.__send__(foreign_key) == id
+  end
 end
 

db/development_structure.sql

@@ -655,6 +655,38 @@ CREATE SEQUENCE post_versions_id_seq
 ALTER SEQUENCE post_versions_id_seq OWNED BY post_versions.id;
 
 
+--
+-- Name: post_votes; Type: TABLE; Schema: public; Owner: -; Tablespace: 
+--
+
+CREATE TABLE post_votes (
+    id integer NOT NULL,
+    post_id integer NOT NULL,
+    user_id integer NOT NULL,
+    created_at timestamp without time zone,
+    updated_at timestamp without time zone
+);
+
+
+--
+-- Name: post_votes_id_seq; Type: SEQUENCE; Schema: public; Owner: -
+--
+
+CREATE SEQUENCE post_votes_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MAXVALUE
+    NO MINVALUE
+    CACHE 1;
+
+
+--
+-- Name: post_votes_id_seq; Type: SEQUENCE OWNED BY; Schema: public; Owner: -
+--
+
+ALTER SEQUENCE post_votes_id_seq OWNED BY post_votes.id;
+
+
 --
 -- Name: posts; Type: TABLE; Schema: public; Owner: -; Tablespace: 
 --
@@ -1145,6 +1177,13 @@ ALTER TABLE pools ALTER COLUMN id SET DEFAULT nextval('pools_id_seq'::regclass);
 ALTER TABLE post_versions ALTER COLUMN id SET DEFAULT nextval('post_versions_id_seq'::regclass);
 
 
+--
+-- Name: id; Type: DEFAULT; Schema: public; Owner: -
+--
+
+ALTER TABLE post_votes ALTER COLUMN id SET DEFAULT nextval('post_votes_id_seq'::regclass);
+
+
 --
 -- Name: id; Type: DEFAULT; Schema: public; Owner: -
 --
@@ -1352,6 +1391,14 @@ ALTER TABLE ONLY post_versions
     ADD CONSTRAINT post_versions_pkey PRIMARY KEY (id);
 
 
+--
+-- Name: post_votes_pkey; Type: CONSTRAINT; Schema: public; Owner: -; Tablespace: 
+--
+
+ALTER TABLE ONLY post_votes
+    ADD CONSTRAINT post_votes_pkey PRIMARY KEY (id);
+
+
 --
 -- Name: posts_pkey; Type: CONSTRAINT; Schema: public; Owner: -; Tablespace: 
 --
@@ -1914,3 +1961,5 @@ INSERT INTO schema_migrations (version) VALUES ('20100214080605');
 INSERT INTO schema_migrations (version) VALUES ('20100215182234');
 
 INSERT INTO schema_migrations (version) VALUES ('20100215213756');
+
+INSERT INTO schema_migrations (version) VALUES ('20100215223541');

db/migrate/20100215223541_create_post_votes.rb

@@ -0,0 +1,13 @@
+class CreatePostVotes < ActiveRecord::Migration
+  def self.up
+    create_table :post_votes do |t|
+      t.column :post_id, :integer, :null => false
+      t.column :user_id, :integer, :null => false
+      t.timestamps
+    end
+  end
+
+  def self.down
+    drop_table :post_votes
+  end
+end

test/unit/comment_test.rb

@@ -38,7 +38,7 @@ class CommentTest < ActiveSupport::TestCase
       post = Factory.create(:post)
       c1 = Factory.create(:comment, :post => post)
       assert_nothing_raised {c1.vote!(user, true)}
-      assert_raise(Comment::VotingError) {c1.vote!(user, true)}
+      assert_raise(CommentVote::Error) {c1.vote!(user, true)}
       assert_equal(1, CommentVote.count)
     
       c2 = Factory.create(:comment, :post => post)

test/unit/comment_vote_test.rb

@@ -1,8 +0,0 @@
-require 'test_helper'
-
-class CommentVoteTest < ActiveSupport::TestCase
-  # Replace this with your real tests.
-  test "the truth" do
-    assert true
-  end
-end

test/unit/post_test.rb

@@ -405,4 +405,16 @@ class PostTest < ActiveSupport::TestCase
       assert_equal(post3.id, relation.first.id)      
     end
   end
+
+  context "Voting on a post" do
+    should "not allow duplicate votes" do
+      user = Factory.create(:user)
+      post = Factory.create(:post)
+      assert_nothing_raised {post.vote!(user, true)}
+      assert_raise(PostVote::Error) {post.vote!(user, true)}
+      post.reload
+      assert_equal(1, PostVote.count)
+      assert_equal(1, post.score)
+    end
+  end
 end