added support for Etag and Last-Modified headers

lib/rack/gridfs.rb

@@ -31,18 +31,22 @@ def initialize(app, options = {})
     def call(env)
       request = Rack::Request.new(env)
       if request.path_info =~ /^\/#{prefix}\/(.+)$/
-        gridfs_request($1)
+        gridfs_request($1, request)
       else
         @app.call(env)
       end
     end
 
-    def gridfs_request(id)
+    def gridfs_request(id, request)
       grid = Mongo::GridFileSystem.new(db)
       file = grid.open(id, 'r')
-      [200, {'Content-Type' => file.content_type}, [file.read]]
+      if request.env['If-None-Match'] == file.files_id.to_s || request.env['If-Modified-Since'] == file.upload_date.httpdate
+        [304, {'Content-Type' => 'text/plain'}, ['Not modified']]
+      else
+        [200, {'Content-Type' => file.content_type, 'Last-Modified' => file.upload_date.httpdate, 'Etag' => file.files_id.to_s}, [file.read]]
+      end
     rescue Mongo::GridError, BSON::InvalidObjectId
-      [404, {'Content-Type' => 'text/plain'}, ['File not found.']]
+      [404, {'Content-Type' => 'text/plain'}, ['File not found.' + id]]
     rescue Mongo::GridFileNotFound
       [404, {'Content-Type' => 'text/plain'}, ['File not found.']]
     end

test/gridfs_test.rb

@@ -1,5 +1,5 @@
 require 'test_helper'
-
+require 'pp'
 class Rack::GridFSTest < Test::Unit::TestCase
   include Rack::Test::Methods
 
@@ -103,22 +103,22 @@ def load_artifact(filename, content_type)
       end
 
       should "return TXT files stored in GridFS" do
-        get "/gridfs/#{@text_id}"
+        get "/gridfs/test.txt"
         assert_equal "Lorem ipsum dolor sit amet.", last_response.body
       end
 
       should "return the proper content type for TXT files" do
-        get "/gridfs/#{@text_id}"
+        get "/gridfs/test.txt"
         assert_equal 'text/plain', last_response.content_type
       end
 
       should "return HTML files stored in GridFS" do
-        get "/gridfs/#{@html_id}"
+        get "/gridfs/test.html"
         assert_match /html.*?body.*Test/m, last_response.body
       end
 
       should "return the proper content type for HTML files" do
-        get "/gridfs/#{@html_id}"
+        get "/gridfs/test.html"
         assert_equal 'text/html', last_response.content_type
       end
 
@@ -129,9 +129,26 @@ def load_artifact(filename, content_type)
 
       should "work for small images" do
         image_id = load_artifact('3wolfmoon.jpg', 'image/jpeg')
-        get "/gridfs/#{image_id}"
+        gridfile = Mongo::Grid.new(db).get(image_id)
+        get "/gridfs/3wolfmoon.jpg"
         assert last_response.ok?
         assert_equal 'image/jpeg', last_response.content_type
+        assert_equal gridfile.upload_date.httpdate, last_response.headers["Last-Modified"]
+        assert_equal gridfile.files_id.to_s, last_response.headers["Etag"]
+      end
+
+      should "return 304 when Etag matches" do
+        image_id = load_artifact('3wolfmoon.jpg', 'image/jpeg')
+        gridfile = Mongo::Grid.new(db).get(image_id)
+        get "/gridfs/3wolfmoon.jpg", nil, {'If-None-Match' => gridfile.files_id.to_s}
+        assert_equal 304, last_response.status
+      end
+
+      should "return 304 when Last-Modified matches" do
+        image_id = load_artifact('3wolfmoon.jpg', 'image/jpeg')
+        gridfile = Mongo::Grid.new(db).get(image_id)
+        get "/gridfs/3wolfmoon.jpg", nil, {'If-Modified-Since' => gridfile.upload_date.httpdate}
+        assert_equal 304, last_response.status
       end
     end