conditionalget.rb in rack-1.3.0.beta

- old
+ new
@@ -18,30 +18,49 @@
     def initialize(app)
       @app = app
     end
 
     def call(env)
-      return @app.call(env) unless %w[GET HEAD].include?(env['REQUEST_METHOD'])
-
-      status, headers, body = @app.call(env)
-      headers = Utils::HeaderHash.new(headers)
-      if etag_matches?(env, headers) || modified_since?(env, headers)
-        status = 304
-        headers.delete('Content-Type')
-        headers.delete('Content-Length')
-        body = []
+      case env['REQUEST_METHOD']
+      when "GET", "HEAD"
+        status, headers, body = @app.call(env)
+        headers = Utils::HeaderHash.new(headers)
+        if status == 200 && fresh?(env, headers)
+          status = 304
+          headers.delete('Content-Type')
+          headers.delete('Content-Length')
+          body = []
+        end
+        [status, headers, body]
+      else
+        @app.call(env)
       end
-      [status, headers, body]
     end
 
   private
-    def etag_matches?(env, headers)
-      etag = headers['Etag'] and etag == env['HTTP_IF_NONE_MATCH']
+
+    def fresh?(env, headers)
+      modified_since = env['HTTP_IF_MODIFIED_SINCE']
+      none_match     = env['HTTP_IF_NONE_MATCH']
+
+      return false unless modified_since || none_match
+
+      success = true
+      success &&= modified_since?(to_rfc2822(modified_since), headers) if modified_since
+      success &&= etag_matches?(none_match, headers) if none_match
+      success
     end
 
-    def modified_since?(env, headers)
-      last_modified = headers['Last-Modified'] and
-        last_modified == env['HTTP_IF_MODIFIED_SINCE']
+    def etag_matches?(none_match, headers)
+      etag = headers['ETag'] and etag == none_match
     end
-  end
 
+    def modified_since?(modified_since, headers)
+      last_modified = to_rfc2822(headers['Last-Modified']) and
+        modified_since >= last_modified
+    end
+
+    def to_rfc2822(since)
+      Time.rfc2822(since) rescue nil
+    end
+  end
 end