Split ActionDispatch http in smaller chunks.

1 files changed, 123 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/http/cache.rb b/actionpack/lib/action_dispatch/http/cache.rb
new file mode 100644
index 0000000000..428e62dc6b
--- /dev/null
+++ b/actionpack/lib/action_dispatch/http/cache.rb
@@ -0,0 +1,123 @@
+module ActionDispatch
+  module Http
+    module Cache
+      module Request
+        def if_modified_since
+          if since = env['HTTP_IF_MODIFIED_SINCE']
+            Time.rfc2822(since) rescue nil
+          end
+        end
+
+        def if_none_match
+          env['HTTP_IF_NONE_MATCH']
+        end
+
+        def not_modified?(modified_at)
+          if_modified_since && modified_at && if_modified_since >= modified_at
+        end
+
+        def etag_matches?(etag)
+          if_none_match && if_none_match == etag
+        end
+
+        # Check response freshness (Last-Modified and ETag) against request
+        # If-Modified-Since and If-None-Match conditions. If both headers are
+        # supplied, both must match, or the request is not considered fresh.
+        def fresh?(response)
+          last_modified = if_modified_since
+          etag          = if_none_match
+
+          return false unless last_modified || etag
+
+          success = true
+          success &&= not_modified?(response.last_modified) if last_modified
+          success &&= etag_matches?(response.etag) if etag
+          success
+        end
+      end
+
+      module Response
+        def cache_control
+          @cache_control ||= {}
+        end
+
+        def last_modified
+          if last = headers['Last-Modified']
+            Time.httpdate(last)
+          end
+        end
+
+        def last_modified?
+          headers.include?('Last-Modified')
+        end
+
+        def last_modified=(utc_time)
+          headers['Last-Modified'] = utc_time.httpdate
+        end
+
+        def etag
+          @etag
+        end
+
+        def etag?
+          @etag
+        end
+
+        def etag=(etag)
+          key = ActiveSupport::Cache.expand_cache_key(etag)
+          @etag = %("#{Digest::MD5.hexdigest(key)}")
+        end
+
+      private
+
+        def handle_conditional_get!
+          if etag? || last_modified? || !@cache_control.empty?
+            set_conditional_cache_control!
+          elsif nonempty_ok_response?
+            self.etag = @body
+
+            if request && request.etag_matches?(etag)
+              self.status = 304
+              self.body = []
+            end
+
+            set_conditional_cache_control!
+          else
+            headers["Cache-Control"] = "no-cache"
+          end
+        end
+
+        def nonempty_ok_response?
+          @status == 200 && string_body?
+        end
+
+        def string_body?
+          !@blank && @body.respond_to?(:all?) && @body.all? { |part| part.is_a?(String) }
+        end
+
+        DEFAULT_CACHE_CONTROL = "max-age=0, private, must-revalidate"
+
+        def set_conditional_cache_control!
+          control = @cache_control
+
+          if control.empty?
+            headers["Cache-Control"] = DEFAULT_CACHE_CONTROL
+          elsif @cache_control[:no_cache]
+            headers["Cache-Control"] = "no-cache"
+          else
+            extras  = control[:extras]
+            max_age = control[:max_age]
+
+            options = []
+            options << "max-age=#{max_age.to_i}" if max_age
+            options << (control[:public] ? "public" : "private")
+            options << "must-revalidate" if control[:must_revalidate]
+            options.concat(extras) if extras
+
+            headers["Cache-Control"] = options.join(", ")
+          end
+        end
+      end
+    end
+  end
+end
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