diff --git a/Gemfile b/Gemfile
index 75a43a941..7f01fde4b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,8 @@
 #ruby=1.9.3
 source 'https://rubygems.org'
-source 'https://jamjam:blueberryjam@www.jamkazam.com/gems/'
+unless ENV["LOCAL_DEV"] == "1"
+	source 'https://jamjam:blueberryjam@www.jamkazam.com/gems/'
+end
 
 # Look for $WORKSPACE, otherwise use "workspace" as dev path.
 workspace = ENV["WORKSPACE"] || "~/workspace"
diff --git a/lib/jam_ruby/models/artifact_update.rb b/lib/jam_ruby/models/artifact_update.rb
index 9367b25c3..d224f6120 100644
--- a/lib/jam_ruby/models/artifact_update.rb
+++ b/lib/jam_ruby/models/artifact_update.rb
@@ -7,12 +7,25 @@ module JamRuby
     
     self.primary_key = 'id'
     attr_accessible :version, :uri, :sha1, :environment, :product
+
+    # ORDER MATTERS HERE- before_save for this method must be declared before mount_uploader: https://github.com/jnicklas/carrierwave/wiki/Known-Issues
+    before_save :update_uri_attributes
     mount_uploader :uri, ArtifactUploader
 
     validate :version, :presence => true
     validate :uri, :presence => true
-    validate :sha1, :presence => false
-    validate :environment, presence => true
+    validate :sha1, :presence => true
+    validate :size, :presence => true
+    validate :environment, :presence => true
     validate :product, :inclusion => {:in => PRODUCTS}
+
+    private
+
+    def update_uri_attributes
+      if uri.present? && uri_changed?
+        self.size = uri.file.size
+        self.sha1 = Digest::MD5.hexdigest(File.read(uri.current_path))
+      end
+    end
   end
 end
diff --git a/spec/jam_ruby/models/artifact_update_spec.rb b/spec/jam_ruby/models/artifact_update_spec.rb
index c4ed36193..24075e310 100644
--- a/spec/jam_ruby/models/artifact_update_spec.rb
+++ b/spec/jam_ruby/models/artifact_update_spec.rb
@@ -1,4 +1,5 @@
 require 'spec_helper'
+require 'digest/md5'
 
 describe ArtifactUpdate do
 
@@ -23,15 +24,14 @@ describe ArtifactUpdate do
     artifact.product = 'JamClient/Win32'
     artifact.version = '0.1.1'
     artifact.uri = File.open(ARTIFACT_FILE)
-    artifact.sha1 = 'blahablahblah'
-
     artifact.save!
 
     artifact.environment.should == "public"
     artifact.product.should == "JamClient/Win32"
     artifact.version.should == "0.1.1"
     File.basename(artifact.uri.path).should == ARTIFACT_FILE
-    artifact.sha1.should == "blahablahblah"
+    artifact.sha1.should == Digest::MD5.hexdigest(File.read(ARTIFACT_FILE))
+    artifact.size.should == File.size(ARTIFACT_FILE)
 
     found = ArtifactUpdate.find_by_product_and_version('JamClient/Win32', '0.1.1')
     artifact.should == found