Trait bound problem when using warp example code

help
#1

Hi!

I'm trying to write a simple web server using warp.
As a first step it should serve all files except one particular type.
I found a similar example in the warp documentation at File in warp::filters::fs - Rust, but when I try to do the same thing in my code, it doesn't compile.

Here's my tokio::main that compiles:

    let repository_path = ".";
    let addr = "0.0.0.0:8000";
    let socket_address: SocketAddr = addr.parse().expect("valid socket address");
    let static_files = warp::any()
	.and(warp::fs::dir(repository_path));
    let server = warp::serve(static_files).try_bind(socket_address);

I followed the example linked above and just added a map, and then it doesn't compile:

    let static_files = warp::any()
	.and(warp::fs::dir(repository_path))
	.map( |reply: warp::filters::fs::File| {
            if reply.path().ends_with(".md") {
                warp::reply::with_header(reply, "Content-Type", "text/MY_markdown").into_response()
            } else {
                reply.into_response()
            };
        },
	);

I get:

error[E0277]: the trait bound `(): warp::Reply` is not satisfied
  --> src/main.rs:34:18
   |
34 |     let server = warp::serve(static_files).try_bind(socket_address);
   |                  ^^^^^^^^^^^ the trait `warp::Reply` is not implemented for `()`
   |
   = note: required because of the requirements on the impl of `warp::Reply` for `((),)`
note: required by a bound in `warp::serve`
  --> /Users/wiz/.cargo/registry/src/github.com-1ecc6299db9ec823/warp-0.3.2/src/server.rs:26:17
   |
26 |     F::Extract: Reply,
   |                 ^^^^^ required by this bound in `warp::serve`

error[E0277]: the trait bound `(): warp::Reply` is not satisfied
   --> src/main.rs:34:44
    |
34  |     let server = warp::serve(static_files).try_bind(socket_address);
    |                                            ^^^^^^^^ the trait `warp::Reply` is not implemented for `()`
    |
    = note: required because of the requirements on the impl of `warp::Reply` for `((),)`
note: required by a bound in `warp::Server::<F>::try_bind`
   --> /Users/wiz/.cargo/registry/src/github.com-1ecc6299db9ec823/warp-0.3.2/src/server.rs:127:35
    |
127 |     <F::Future as TryFuture>::Ok: Reply,
    |                                   ^^^^^ required by this bound in `warp::Server::<F>::try_bind`

For more information about this error, try `rustc --explain E0277`.

Can someone please explain the warning to me so I can fix it?

Is the example incorrect or am I doing something wrong/missing something?

Thanks for reading so far!

#2

Remove the semicolon following the if:



     let static_files = warp::any()
     .and(warp::fs::dir(repository_path))
     .map( |reply: warp::filters::fs::File| {
             if reply.path().ends_with(".md") {
                 warp::reply::with_header(reply, "Content-Type", "text/MY_markdown").into_response()
             } else {
                 reply.into_response()
-            };
+            }
         },
 	);

This will return the Response from the closure, instead of immediately dropping it.

#3

That did it. Such a silly little mistake, and still it would have taken me a long time to get that from the error message.
Thanks a lot, @LegionMammal978 !