diff options
Diffstat (limited to 'actionpack/lib/action_dispatch/http')
-rw-r--r-- | actionpack/lib/action_dispatch/http/cache.rb | 64 | ||||
-rw-r--r-- | actionpack/lib/action_dispatch/http/headers.rb | 2 | ||||
-rw-r--r-- | actionpack/lib/action_dispatch/http/request.rb | 1 |
3 files changed, 50 insertions, 17 deletions
diff --git a/actionpack/lib/action_dispatch/http/cache.rb b/actionpack/lib/action_dispatch/http/cache.rb index 4bd727c14e..9fa2e38ae3 100644 --- a/actionpack/lib/action_dispatch/http/cache.rb +++ b/actionpack/lib/action_dispatch/http/cache.rb @@ -17,9 +17,7 @@ module ActionDispatch end def if_none_match_etags - (if_none_match ? if_none_match.split(/\s*,\s*/) : []).collect do |etag| - etag.gsub(/^\"|\"$/, "") - end + if_none_match ? if_none_match.split(/\s*,\s*/) : [] end def not_modified?(modified_at) @@ -28,8 +26,8 @@ module ActionDispatch def etag_matches?(etag) if etag - etag = etag.gsub(/^\"|\"$/, "") - if_none_match_etags.include?(etag) + validators = if_none_match_etags + validators.include?(etag) || validators.include?('*') end end @@ -80,27 +78,63 @@ module ActionDispatch set_header DATE, utc_time.httpdate end - # This method allows you to set the ETag for cached content, which - # will be returned to the end user. + # This method sets a weak ETag validator on the response so browsers + # and proxies may cache the response, keyed on the ETag. On subsequent + # requests, the If-None-Match header is set to the cached ETag. If it + # matches the current ETag, we can return a 304 Not Modified response + # with no body, letting the browser or proxy know that their cache is + # current. Big savings in request time and network bandwidth. + # + # Weak ETags are considered to be semantically equivalent but not + # byte-for-byte identical. This is perfect for browser caching of HTML + # pages where we don't care about exact equality, just what the user + # is viewing. # - # By default, Action Dispatch sets all ETags to be weak. - # This ensures that if the content changes only semantically, - # the whole page doesn't have to be regenerated from scratch - # by the web server. With strong ETags, pages are compared - # byte by byte, and are regenerated only if they are not exactly equal. - def etag=(etag) - key = ActiveSupport::Cache.expand_cache_key(etag) - super %(W/"#{Digest::MD5.hexdigest(key)}") + # Strong ETags are considered byte-for-byte identical. They allow a + # browser or proxy cache to support Range requests, useful for paging + # through a PDF file or scrubbing through a video. Some CDNs only + # support strong ETags and will ignore weak ETags entirely. + # + # Weak ETags are what we almost always need, so they're the default. + # Check out `#strong_etag=` to provide a strong ETag validator. + def etag=(weak_validators) + self.weak_etag = weak_validators + end + + def weak_etag=(weak_validators) + set_header 'ETag', generate_weak_etag(weak_validators) + end + + def strong_etag=(strong_validators) + set_header 'ETag', generate_strong_etag(strong_validators) end def etag?; etag; end + # True if an ETag is set and it's a weak validator (preceded with W/) + def weak_etag? + etag? && etag.starts_with?('W/"') + end + + # True if an ETag is set and it isn't a weak validator (not preceded with W/) + def strong_etag? + etag? && !weak_etag? + end + private DATE = 'Date'.freeze LAST_MODIFIED = "Last-Modified".freeze SPECIAL_KEYS = Set.new(%w[extras no-cache max-age public private must-revalidate]) + def generate_weak_etag(validators) + "W/#{generate_strong_etag(validators)}" + end + + def generate_strong_etag(validators) + %("#{Digest::MD5.hexdigest(ActiveSupport::Cache.expand_cache_key(validators))}") + end + def cache_control_segments if cache_control = _cache_control cache_control.delete(' ').split(',') diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb index 5c3b7245d6..69a934b7cd 100644 --- a/actionpack/lib/action_dispatch/http/headers.rb +++ b/actionpack/lib/action_dispatch/http/headers.rb @@ -5,7 +5,7 @@ module ActionDispatch # env = { "CONTENT_TYPE" => "text/plain", "HTTP_USER_AGENT" => "curl/7.43.0" } # headers = ActionDispatch::Http::Headers.new(env) # headers["Content-Type"] # => "text/plain" - # headers["User-Agent"] # => "curl/7/43/0" + # headers["User-Agent"] # => "curl/7.43.0" # # Also note that when headers are mapped to CGI-like variables by the Rack # server, both dashes and underscores are converted to underscores. This diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb index 316a9f08b7..b0ed681623 100644 --- a/actionpack/lib/action_dispatch/http/request.rb +++ b/actionpack/lib/action_dispatch/http/request.rb @@ -337,7 +337,6 @@ module ActionDispatch else self.session = {} end - self.flash = nil end def session=(session) #:nodoc: |