| # Copyright (c) 2008 The Committers |
| |
| # Permission is hereby granted, free of charge, to any person obtaining a copy |
| # of this software and associated documentation files (the "Software"), to |
| # deal in the Software without restriction, including without limitation the |
| # rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| # sell copies of the Software, and to permit persons to whom the Software is |
| # furnished to do so, subject to the following conditions: |
| # |
| # The above copyright notice and this permission notice shall be included in |
| # all copies or substantial portions of the Software. |
| # |
| # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| # THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER |
| # IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| |
| module Rack |
| # Automatically sets the ETag header on all String bodies. |
| # |
| # The ETag header is skipped if ETag or Last-Modified headers are sent or if |
| # a sendfile body (body.responds_to :to_path) is given (since such cases |
| # should be handled by apache/nginx). |
| # |
| # On initialization, you can pass two parameters: a Cache-Control directive |
| # used when Etag is absent and a directive when it is present. The first |
| # defaults to nil, while the second defaults to "max-age=0, privaute, must-revalidate" |
| class ETag |
| |
| def initialize(app, no_cache_control = nil, cache_control = nil) |
| @app = app |
| @cache_control = cache_control || "max-age=0, private, must-revalidate" |
| @no_cache_control = no_cache_control |
| end |
| |
| def call(env) |
| status, headers, body = @app.call(env) |
| |
| if etag_status?(status) && etag_body?(body) && !http_caching?(headers) |
| digest, body = digest_body(body) |
| headers['ETag'] = digest.to_s if digest |
| end |
| |
| if not headers['Cache-Control'] and digest |
| headers['Cache-Control'] = digest ? @cache_control : @no_cache_control |
| end |
| |
| [status, headers, body] |
| end |
| |
| private |
| |
| def etag_status?(status) |
| status == 200 || status == 201 |
| end |
| |
| def etag_body?(body) |
| !body.respond_to?(:to_path) |
| end |
| |
| def http_caching?(headers) |
| headers.key?('ETag') || headers.key?('Last-Modified') |
| end |
| |
| def digest_body(body) |
| parts = [] |
| if RUBY_VERSION =~ /^1\.8/ |
| body.each { |part, b| parts << part } |
| else |
| body.each { |part| parts << part } |
| end |
| string_body = parts.join |
| digest = Digest::MD5.hexdigest(string_body) unless string_body.empty? |
| [digest, parts] |
| end |
| end |
| end |
| |