Using the hyper crate, I'm making an HTTP request to an endpoint then subsequently attempting to pass the response Body to a third-party library that expects a parameter to be a Futures crate Stream.
This results in a type error.
Cargo.toml
[dependencies] bytes = "1.0.1" http = "0.2.3" tokio = { version = "1.1.0", features = ["full"] } hyper = { version = "0.14.2", features = ["full"] } hyper-tls = "0.5.0" futures = "0.3.12" Example
use std::io; use bytes::Bytes; use hyper::{Client, Body}; use hyper_tls::HttpsConnector; use http::Request; use futures::stream::Stream; // ---- begin third-party library type ConsumableStream = dyn Stream<Item = Result<Bytes, io::Error>> + Send + Sync + 'static; async fn stream_consumer(_: &mut ConsumableStream) { // consume stream... } // ---- end third-party library #[tokio::main] async fn main() { let uri = "https://jsonplaceholder.typicode.com/todos/1"; let https = HttpsConnector::new(); let client = Client::builder().build::<_, Body>(https); let request = Request::get(uri).body(Body::empty()).unwrap(); let response = client.request(request).await.unwrap(); let mut body = Box::new(response.into_body()); stream_consumer(&mut body).await; } Cargo Run Output
error[E0271]: type mismatch resolving `<std::boxed::Box<hyper::body::body::Body> as futures_core::stream::Stream>::Item == std::result::Result<bytes::bytes::Bytes, std::io::Error>` --> src/bin/future_streams.rs:24:21 | 24 | stream_consumer(&mut body).await; | ^^^^^^^^^ expected struct `std::io::Error`, found struct `hyper::error::Error` | = note: expected enum `std::result::Result<_, std::io::Error>` found enum `std::result::Result<_, hyper::error::Error>` = note: required for the cast to the object type `(dyn futures_core::stream::Stream<Item = std::result::Result<bytes::bytes::Bytes, std::io::Error>> + std::marker::Send + std::marker::Sync + 'static)` error: aborting due to previous error; 1 warning emitted For more information about this error, try `rustc --explain E0271`. error: could not compile `rustest`. To learn more, run the command again with --verbose. Question
What's the most efficient way to use the hyper Body with as a function parameter of expected Future Stream type?
