From 5dd1d26b202b7cfaf8d4661a8ff059353e60cb0e Mon Sep 17 00:00:00 2001
From: Garret Alfert <garret@5apps.com>
Date: Fri, 9 Aug 2013 10:56:04 +0200
Subject: [PATCH] Set and check ETag headers

---
 lib/remote_storage/riak.rb | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/lib/remote_storage/riak.rb b/lib/remote_storage/riak.rb
index 76afbf1..19c2035 100644
--- a/lib/remote_storage/riak.rb
+++ b/lib/remote_storage/riak.rb
@@ -40,8 +40,11 @@ module RemoteStorage
     def get_data(user, directory, key)
       object = data_bucket.get("#{user}:#{directory}:#{key}")
 
+      server.halt 304 if server.env["HTTP_IF_NONE_MATCH"] == object.etag
+
       server.headers["Content-Type"] = object.content_type
       server.headers["Last-Modified"] = last_modified_date_for(object)
+      server.headers["ETag"] = object.etag
 
       if binary_key = object.meta["binary_key"]
         object = cs_binary_bucket.files.get(binary_key[0])
@@ -66,10 +69,14 @@ module RemoteStorage
 
     def get_directory_listing(user, directory)
       directory_object = directory_bucket.get("#{user}:#{directory}")
+
+      server.halt 304 if server.env["HTTP_IF_NONE_MATCH"] == directory_object.etag
+
       timestamp = directory_object.data.to_i
       timestamp /= 1000 if timestamp.to_s.length == 13
       server.headers["Content-Type"] = "application/json"
       server.headers["Last-Modified"] = Time.at(timestamp).to_s(:rfc822)
+      server.headers["ETag"] = directory_object.etag
 
       listing = directory_listing(user, directory)
 
@@ -81,6 +88,10 @@ module RemoteStorage
     def put_data(user, directory, key, data, content_type=nil)
       object = build_data_object(user, directory, key, data, content_type)
 
+      if required_match = server.env["HTTP_IF_MATCH"]
+        server.halt 412 unless required_match == object.etag
+      end
+
       object_exists = !object.raw_data.nil?
       existing_object_size = object_size(object)
 
@@ -102,6 +113,7 @@ module RemoteStorage
 
       update_all_directory_objects(user, directory, timestamp)
 
+      server.headers["ETag"] = object.etag
       server.halt 200
     rescue ::Riak::HTTPFailedRequest
       server.halt 422
@@ -110,6 +122,11 @@ module RemoteStorage
     def delete_data(user, directory, key)
       object = data_bucket.get("#{user}:#{directory}:#{key}")
       existing_object_size = object_size(object)
+      etag = object.etag
+
+      if match_requirement = server.env["HTTP_IF_MATCH"]
+        server.halt 412 unless match_requirement == etag
+      end
 
       if binary_key = object.meta["binary_key"]
         object = cs_binary_bucket.files.get(binary_key[0])
@@ -125,6 +142,7 @@ module RemoteStorage
       timestamp = (Time.now.to_f * 1000).to_i
       delete_or_update_directory_objects(user, directory, timestamp)
 
+      server.headers["ETag"] = etag
       server.halt riak_response[:code]
     rescue ::Riak::HTTPFailedRequest
       server.halt 404