Changelog - 2026-11-03

RequestBodyEncoder types its body, and ResponseReader reads a file name

New Feature Enhancement

In one line. RequestBodyEncoder.encode now says what body it built, so a FormData goes to an API that takes string | object without a cast, and ResponseReader.readFilename gives you the file name of a download.

The example is in Encode a body and read a file name yourself.

What changed

• A typed body. encode({ bodyType, body }) returns body: FormData for form-data and body: URLSearchParams for x-www-form-urlencoded. For json, none, binary or no bodyType it returns the body you passed, with its type. A bodyType that is only a string still gives body: unknown. Nothing changes at run time.
• ResponseReader.readFilename({ headers }). It returns the name in Content-Disposition, filename*= (UTF-8, decoded) before filename=, or undefined. ResponseReader.read still returns the name as filename and behaves as before.

Who is affected

• An app or a subclass of DefaultNetworkRequestService that calls RequestBodyEncoder.encode. No action needed. If your code assigned the body to a variable typed unknown, it still compiles.
• An app that parsed Content-Disposition itself. You can call ResponseReader.readFilename instead.

See Network.