How to Get Response Body in middleware

[caibirdme]

I want to impl a middleware that can log request and response body

#[async_trait]
impl Middleware for LoggingMiddlware {
    async fn handle(
        &self,
        req: Request,
        extensions: &mut Extensions,
        next: Next<'_>,
    ) -> ReqResult<Response> {
        req.body().clone()
			.and_then(|b| b.as_bytes())
			.and_then(|v| {
				println!("Request: {:?}", std::str::from_utf8(v).unwrap());
				Some(())
			});
        let res = next.run(req, extensions).await;
        // since response is a future
        // how can I get its response body without changing it?
        res
    }
}

[urosjovanovic]

Any updates on this one? I had the same scenario, trying to log the response body within the logger middleware but the current design just doesn't support this. In the end, I needed to pull out my logging logic out of the middleware and wrap around HTTP client's execute method in order to invoke the .bytes() method.

I guess the culprit is that body streaming methods such as .bytes() are consuming the whole Response object (self) so it becomes unusable after it is invoked.

[lcmgh]

I am interested in adding a body trace to my OTLP span but that seems even more difficult as fn on_request_end ofReqwestOtelSpanBackend is not even async.

https://docs.rs/reqwest-tracing/latest/reqwest_tracing/