diff --git a/versions/3.0.4.md b/versions/3.0.4.md index 03da3f7ddc..7045ec6cfd 100644 --- a/versions/3.0.4.md +++ b/versions/3.0.4.md @@ -1753,8 +1753,9 @@ It is not currently possible to correlate schema properties with unnamed, ordere Note that there are significant restrictions on what headers can be used with `multipart` media types in general ([RFC2046 §5.1](https://www.rfc-editor.org/rfc/rfc2046.html#section-5.1)) and `multi-part/form-data` in particular ([RFC7578 §4.8](https://www.rfc-editor.org/rfc/rfc7578.html#section-4.8)). Note also that `Content-Transfer-Encoding` is deprecated for `multipart/form-data` ([RFC7578 §4.7](https://www.rfc-editor.org/rfc/rfc7578.html#section-4.7)) where binary data is supported, as it is in HTTP. -Using `format: byte` for a multipart field is equivalent to setting `Content-Transfer-Encoding: base64`. -If `format: byte` is used along with setting a different `Content-Transfer-Encoding` value with the `headers` field, the result is undefined. + +Using `format: byte` for a multipart field is equivalent to specifying an [Encoding Object](#encodingObject) with a `headers` field containing `Content-Transfer-Encoding` with a schema that requires the value `base64`. +If `format: byte` is used for a multipart field that has an Encoding Object with a `headers` field containing `Content-Transfer-Encoding` with a schema that disallows `base64`, the result is undefined for serialization and parsing. Per the JSON Schema specification, `contentMediaType` without `contentEncoding` present is treated as if `contentEncoding: identity` were present. While useful for embedding text documents such as `text/html` into JSON strings, it is not useful for a `multipart/form-data` part, as it just causes the document to be treated as `text/plain` instead of its actual media type. Use the Encoding Object without `contentMediaType` if no `contentEncoding` is required.