LibWeb/Fetch: Implement build_content_range(start, end, full_length)

Author: https://github.com/rmg-x
Commit: https://github.com/LadybirdBrowser/ladybird/commit/4e48298414e
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2434
Reviewed-by: https://github.com/tcl3 ✅

Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.cpp

@@ -832,6 +832,19 @@ Variant<Vector<ByteBuffer>, ExtractHeaderParseFailure, Empty> extract_header_lis
     return values;
 }
 
+// https://fetch.spec.whatwg.org/#build-a-content-range
+ByteString build_content_range(u64 const& range_start, u64 const& range_end, u64 const& full_length)
+{
+    // 1. Let contentRange be `bytes `.
+    // 2. Append rangeStart, serialized and isomorphic encoded, to contentRange.
+    // 3. Append 0x2D (-) to contentRange.
+    // 4. Append rangeEnd, serialized and isomorphic encoded to contentRange.
+    // 5. Append 0x2F (/) to contentRange.
+    // 6. Append fullLength, serialized and isomorphic encoded to contentRange.
+    // 7. Return contentRange.
+    return ByteString::formatted("bytes {}-{}/{}", String::number(range_start), String::number(range_end), String::number(full_length));
+}
+
 // https://fetch.spec.whatwg.org/#simple-range-header-value
 Optional<RangeHeaderValue> parse_single_range_header_value(ReadonlyBytes const value, bool const allow_whitespace)
 {

Libraries/LibWeb/Fetch/Infrastructure/HTTP/Headers.h

@@ -93,6 +93,7 @@ struct ExtractHeaderParseFailure {
 [[nodiscard]] bool is_request_body_header_name(ReadonlyBytes);
 [[nodiscard]] Optional<Vector<ByteBuffer>> extract_header_values(Header const&);
 [[nodiscard]] Variant<Vector<ByteBuffer>, ExtractHeaderParseFailure, Empty> extract_header_list_values(ReadonlyBytes, HeaderList const&);
+[[nodiscard]] ByteString build_content_range(u64 const& range_start, u64 const& range_end, u64 const& full_length);
 [[nodiscard]] Optional<RangeHeaderValue> parse_single_range_header_value(ReadonlyBytes, bool);
 [[nodiscard]] ByteBuffer default_user_agent_value();