Fix StaticCache middleware (#167)

* StaticCache. Send Date header in response

* StaticCahe. Use current time in UTC

* StaticCache. Don't cache Expires header

Author: andrykonchin

lib/rack/contrib/static_cache.rb

@@ -1,3 +1,5 @@
+require 'time'
+
 module Rack
 
   #
@@ -68,7 +70,6 @@ def initialize(app, options={})
         @version_regex = options.fetch(:version_regex, /-[\d.]+([.][a-zA-Z][\w]+)?$/)
       end
       @duration_in_seconds = self.duration_in_seconds
-      @duration_in_words    = self.duration_in_words
     end
 
     def call(env)
@@ -83,14 +84,15 @@ def call(env)
         status, headers, body = @file_server.call(env)
         if @no_cache[url].nil?
           headers['Cache-Control'] ="max-age=#{@duration_in_seconds}, public"
-          headers['Expires'] = @duration_in_words
+          headers['Expires'] = duration_in_words
         end
+        headers['Date'] = Time.now.httpdate
         [status, headers, body]
       end
     end
 
     def duration_in_words
-      (Time.now + self.duration_in_seconds).strftime '%a, %d %b %Y %H:%M:%S GMT'
+      (Time.now.utc + self.duration_in_seconds).httpdate
     end
 
     def duration_in_seconds

rack-contrib.gemspec

@@ -51,6 +51,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rake', '~> 10.4', '>= 10.4.2'
   s.add_development_dependency 'rdoc', '~> 5.0'
   s.add_development_dependency 'ruby-prof', '~> 0.17'
+  s.add_development_dependency 'timecop', '~> 0.9'
 
   s.homepage = "https://github.com/rack/rack-contrib/"
   s.rdoc_options = ["--line-numbers", "--inline-source", "--title", "rack-contrib", "--main", "README"]

test/gemfiles/minimum_versions

@@ -17,3 +17,4 @@ gem 'nbio-csshttprequest', '= 1.0.2'
 gem 'rdoc',                '= 5.0.0'
 gem 'rake',                '= 10.4.2'
 gem 'ruby-prof',           '= 0.17.0'
+gem 'timecop',             '= 0.4.1'

test/spec_rack_static_cache.rb

@@ -3,6 +3,7 @@
 require 'rack'
 require 'rack/contrib/static_cache'
 require 'rack/mock'
+require 'timecop'
 
 class DummyApp
   def call(env)
@@ -16,8 +17,12 @@ def static_root
   end
 
   def request(options)
+    Rack::MockRequest.new(build_middleware(options))
+  end
+
+  def build_middleware(options)
     options = { :root => static_root }.merge(options)
-    Rack::MockRequest.new(Rack::StaticCache.new(DummyApp.new, options))
+    Rack::StaticCache.new(DummyApp.new, options)
   end
 
   describe "with a default app request" do
@@ -52,6 +57,32 @@ def get_request(path)
       )
     end
 
+    it "should set Expires header based on current UTC time" do
+      Timecop.freeze(DateTime.parse("2020-03-28 23:51 UTC")) do
+        _(get_request("/statics/test").headers['Expires']).must_match("Sun, 28 Mar 2021 23:51:00 GMT") # now + 1 year
+      end
+    end
+
+    it "should not cache expiration date between requests" do
+      middleware = build_middleware(:urls => ["/statics"])
+
+      Timecop.freeze(DateTime.parse("2020-03-28 23:41 UTC")) do
+        r = Rack::MockRequest.new(middleware)
+        _(r.get("/statics/test").headers["Expires"]).must_equal "Sun, 28 Mar 2021 23:41:00 GMT" # time now + 1 year
+      end
+
+      Timecop.freeze(DateTime.parse("2020-03-28 23:51 UTC")) do
+        r = Rack::MockRequest.new(middleware)
+        _(r.get("/statics/test").headers["Expires"]).must_equal "Sun, 28 Mar 2021 23:51:00 GMT" # time now + 1 year
+      end
+    end
+
+    it "should set Date header with current GMT time" do
+      Timecop.freeze(DateTime.parse('2020-03-28 22:51 UTC')) do
+        _(get_request("/statics/test").headers['Date']).must_equal 'Sat, 28 Mar 2020 22:51:00 GMT'
+      end
+    end
+
     it "should return 404s if url root is known but it can't find the file" do
       _(get_request("/statics/non-existent").not_found?).must_equal(true)
     end