How to upload / download using axum and AsyncRead?

[frederikhors]

After hyper v1 revolution (they removed the native hyper Client moving it in "legacy" crate in another hyper-util crate) I would like to use ureq (instead of reqwest or others).

I need to use it in multiple places but one of them is driving me crazy (along with #704).

I'm using "axum" and I need to "upload" and "download" some files, but I don't understand how to do it.

The actual code is:

use tokio::io::AsyncRead;

impl Trait for S3Client {
    async fn put_file(
        &self,
        filename: &str,
        size: i64,
        reader: Pin<Box<(dyn AsyncRead + Send)>>,
    ) -> Result<()> {
        self.hyper_client
            .request(
                hyper::Request::builder()
                    .method(Method::PUT)
                    .uri(get_uri())
                    .header(header::CONTENT_LENGTH, size)
                    .body(hyper::Body::wrap_stream(ReaderStream::new(reader)))
                    .unwrap(),
            )
            .await?;

        Ok(())
    }

    async fn get_file(&self, filename: &str) -> Result<Pin<Box<dyn AsyncRead + Send + Sync>>> {
        let resp = self
            .hyper_client
            .uri(get_uri())
            .await?
            .into_body()
            .map_err(|e| futures::io::Error::new(futures::io::ErrorKind::Other, e))
            .into_async_read()
            .compat();

        Ok(Box::pin(resp))
    }
}

with reader: Pin<Box<(dyn AsyncRead + Send)>> coming from:

use axum::body::Body;

pub async fn upload(
    //...
    request: Request,
) -> Result<Response, StatusCode> {
    //...

    let stream = request
        .into_body()
        .into_data_stream()
        .map_err(|err| io::Error::new(io::ErrorKind::Other, err));
    
    //...
}

pub async fn download(
    State(app_state): State<Arc<AppState>>,
    session: Extension<Session>,
    Query(params): Query<Vec<(String, String)>>,
) -> Result<Response, StatusCode> {
    let Some(res) = get_file(...);

    //...

    Ok(
      Response::builder()
        .body(Body::from_stream(ReaderStream::new(res.1)))
        .unwrap()
    )
}

I think the first problem is with AsyncRead, right?

[algesten]

Hi! Yeah, I AsyncRead is not going to be a great fit with ureq, since ureq is (deliberately) sync. I'm sure it's possible by spawning blocking polls for the AsyncRead, but it kinda goes against the idea of async.

[frederikhors]

Yeah. Sorry, my mistake.