LibHTTP: Correctly normalize header whitespace in cache utilities

We also shouldn't trim whitespace at all when reading headers from the
cache index. We store them as-is and should therefore read them as-is.

Libraries/LibHTTP/Cache/CacheIndex.cpp

@@ -38,11 +38,11 @@ static NonnullRefPtr<HeaderList> deserialize_headers(StringView serialized_heade
         if (!index.has_value())
             return;
 
-        auto name = serialized_header.substring_view(0, *index).trim_whitespace();
+        auto name = serialized_header.substring_view(0, *index);
         if (is_header_exempted_from_storage(name))
             return;
 
-        auto value = serialized_header.substring_view(*index + 1).trim_whitespace();
+        auto value = serialized_header.substring_view(*index + 1);
         headers->append({ name, value });
     });
 

Libraries/LibHTTP/Cache/Utilities.cpp

@@ -643,7 +643,7 @@ ByteString normalize_request_vary_header_values(StringView header, HeaderList co
             }
 
             value.view().for_each_split_view(","sv, SplitBehavior::Nothing, [&](StringView field) {
-                values.append(field.trim_whitespace());
+                values.append(normalize_header_value(field));
             });
             return IterationDecision::Continue;
         });

Libraries/LibHTTP/HeaderList.h

@@ -83,7 +83,7 @@ public:
             IterationDecision result;
 
             value.for_each_split_view(","sv, SplitBehavior::Nothing, [&](StringView header) -> IterationDecision {
-                result = callback(header.trim_whitespace());
+                result = callback(normalize_header_value(header));
                 return result;
             });
 

Tests/LibWeb/Text/input/Cache/http-disk-cache.html

@@ -955,6 +955,31 @@
             expectCacheStatus(url, response, "read-from-cache");
         })();
 
+        // Requsts with a Vary header with improper whitespace do not match normal response headers.
+        await (async () => {
+            url = await createRequest("/cache-test/vary/vertical-tab", {
+                headers: {
+                    "Cache-Control": "max-age=10",
+                    Vary: "Accept\v",
+                },
+            });
+
+            response = await cacheFetch(url, {
+                headers: {
+                    Accept: "text/html",
+                },
+            });
+            expectCacheStatus(url, response, "written-to-cache");
+
+            // This would normally be a Vary mismatch, but "Accept\v" does not match "Accept".
+            response = await cacheFetch(url, {
+                headers: {
+                    Accept: "text/javascript",
+                },
+            });
+            expectCacheStatus(url, response, "read-from-cache");
+        })();
+
         // Responses with a Vary header that matches subsequent request headers after normalization may be used.
         await (async () => {
             url = await createRequest("/cache-test/vary/normalization", {