87 lines
3.2 KiB
Ruby
87 lines
3.2 KiB
Ruby
module ActionController
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module ConditionalGet
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extend ActiveSupport::Concern
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include RackDelegation
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include Head
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# Sets the etag, last_modified, or both on the response and renders a
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# "304 Not Modified" response if the request is already fresh.
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#
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# Parameters:
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# * <tt>:etag</tt>
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# * <tt>:last_modified</tt>
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# * <tt>:public</tt> By default the Cache-Control header is private, set this to true if you want your application to be cachable by other devices (proxy caches).
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#
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# Example:
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#
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# def show
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# @article = Article.find(params[:id])
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# fresh_when(:etag => @article, :last_modified => @article.created_at.utc, :public => true)
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# end
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#
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# This will render the show template if the request isn't sending a matching etag or
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# If-Modified-Since header and just a "304 Not Modified" response if there's a match.
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#
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def fresh_when(options)
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options.assert_valid_keys(:etag, :last_modified, :public)
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response.etag = options[:etag] if options[:etag]
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response.last_modified = options[:last_modified] if options[:last_modified]
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response.cache_control[:public] = true if options[:public]
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head :not_modified if request.fresh?(response)
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end
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# Sets the etag and/or last_modified on the response and checks it against
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# the client request. If the request doesn't match the options provided, the
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# request is considered stale and should be generated from scratch. Otherwise,
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# it's fresh and we don't need to generate anything and a reply of "304 Not Modified" is sent.
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#
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# Parameters:
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# * <tt>:etag</tt>
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# * <tt>:last_modified</tt>
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# * <tt>:public</tt> By default the Cache-Control header is private, set this to true if you want your application to be cachable by other devices (proxy caches).
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#
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# Example:
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#
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# def show
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# @article = Article.find(params[:id])
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#
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# if stale?(:etag => @article, :last_modified => @article.created_at.utc)
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# @statistics = @article.really_expensive_call
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# respond_to do |format|
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# # all the supported formats
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# end
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# end
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# end
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def stale?(options)
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fresh_when(options)
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!request.fresh?(response)
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end
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# Sets a HTTP 1.1 Cache-Control header. Defaults to issuing a "private" instruction, so that
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# intermediate caches shouldn't cache the response.
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#
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# Examples:
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# expires_in 20.minutes
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# expires_in 3.hours, :public => true
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# expires in 3.hours, 'max-stale' => 5.hours, :public => true
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#
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# This method will overwrite an existing Cache-Control header.
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# See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more possibilities.
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def expires_in(seconds, options = {}) #:doc:
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response.cache_control.merge!(:max_age => seconds, :public => options.delete(:public))
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options.delete(:private)
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response.cache_control[:extras] = options.map {|k,v| "#{k}=#{v}"}
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end
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# Sets a HTTP 1.1 Cache-Control header of "no-cache" so no caching should occur by the browser or
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# intermediate caches (like caching proxy servers).
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def expires_now #:doc:
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response.cache_control.replace(:no_cache => true)
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end
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end
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end
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