Merge pull request #65 from Shopify/weak_304

Relaxed 304 If-None-Match test to support weak key
Shopify · Mar 23, 2023 · 82ca12e · 82ca12e
2 parents 1ff3caa + 6821ecf
commit 82ca12e
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Showing 2 changed files with 18 additions and 1 deletion.
diff --git a/lib/response_bank/response_cache_handler.rb b/lib/response_bank/response_cache_handler.rb
@@ -113,7 +113,12 @@ def serving_from_noncurrent_but_recent_version_acceptable?
     end
 
     def serve_from_browser_cache(cache_key_hash)
-      if @env["HTTP_IF_NONE_MATCH"] == cache_key_hash
+      # Support for Etag variations including:
+      # If-None-Match: abc
+      # If-None-Match: "abc"
+      # If-None-Match: W/"abc"
+      # If-None-Match: "abc", "def"
+      if !@env["HTTP_IF_NONE_MATCH"].nil? && @env["HTTP_IF_NONE_MATCH"].include?(cache_key_hash)
         @env['cacheable.miss']  = false
         @env['cacheable.store'] = 'client'
 

diff --git a/test/response_cache_handler_test.rb b/test/response_cache_handler_test.rb
@@ -74,6 +74,18 @@ def test_client_cache_hit
     assert_env(false, 'client')
   end
 
+  def test_client_cache_hit_quoted
+    controller.request.env['HTTP_IF_NONE_MATCH'] = "\"#{handler.versioned_key_hash}\""
+    handler.run!
+    assert_env(false, 'client')
+  end
+
+  def test_client_cache_hit_weak
+    controller.request.env['HTTP_IF_NONE_MATCH'] = "W/\"#{handler.versioned_key_hash}\""
+    handler.run!
+    assert_env(false, 'client')
+  end
+
   def test_server_cache_hit
     controller.request.env['gzip'] = false
     @cache_store.expects(:read).with(handler.versioned_key_hash, raw: true).returns(page_serialized)