hyper `write_stream` with `ContentLength` about multipart HOT 5 CLOSED

The first idea was to use

request.headers_mut().set(ContentLength(meta_json.len() as u64 + size_srpm as u64));

but that results in

failed to write whole buffer

when spawning the multipart struct

from multipart.

The following produces the same error:

    let mut request = Request::with_connector(Method::Post, url, &connector)
   					.chain_err(||"Failed to create POST request")?;
    request.headers_mut().set(
			ContentType(
		 		Mime(
		 			TopLevel::Multipart, SubLevel::Ext("form-data".into()),
		 			vec![(Attr::Ext("boundary".into()), Value::Ext(boundary.into()))]
		 			)
		 		)
		 	);
    request.headers_mut().set(ContentLength(meta_json.len() as u64 + size_srpm as u64));

    let mut multipart = Multipart::from_request(request).chain_err(||"Failed to create multipart request")?;

from multipart.

Total length is 1260944 [ bytes ] which is not too much to allocate ..

from multipart.

The ContentLength value has to be the whole size of the body, including multipart boundaries and field headers.

If you use Multipart::from_request_sized() it will set the ContentLength header correctly, though the implementation is incredibly naive; it just writes the whole request to an in-memory buffer to get the length that way and then writes it out to the stream in one fell swoop.

from multipart.

Understood, I ended up doing exactly that.

I think there is no other way around that since the headers are only to be written with Request where body is only to be written with Request given hyper's implementation.

from multipart.