5 # Middleware that enables conditional GET using If-None-Match and
6 # If-Modified-Since. The application should set either or both of the
7 # Last-Modified or Etag response headers according to RFC 2616. When
8 # either of the conditions is met, the response body is set to be zero
9 # length and the response status is set to 304 Not Modified.
11 # Applications that defer response body generation until the body's each
12 # message is received will avoid response body generation completely when
13 # a conditional GET matches.
15 # Adapted from Michael Klishin's Merb implementation:
16 # http://github.com/wycats/merb-core/tree/master/lib/merb-core/rack/middleware/conditional_get.rb
23 return @app.call(env) unless %w
[GET HEAD
].include?(env['REQUEST_METHOD'])
25 status
, headers
, body
= @app.call(env)
26 headers
= Utils
::HeaderHash.new(headers
)
27 if etag_matches
?(env, headers
) || modified_since
?(env, headers
)
31 [status
, headers
, body
]
35 def etag_matches
?(env, headers
)
36 etag
= headers
['Etag'] and etag
== env['HTTP_IF_NONE_MATCH']
39 def modified_since
?(env, headers
)
40 last_modified
= headers
['Last-Modified'] and
41 last_modified
== env['HTTP_IF_MODIFIED_SINCE']