How can I get the request protocol/scheme?

[ghost]

How can I get the incoming request's protocol/scheme, e.g. http, https, etc.?
Alternatively how can I get the full URI of the request starting with the protocol/scheme, e.g. http://..., https://..., erc.?
Finally, how can I do either of the above in a middleware/layer and in a request handler?

[davidpdrsn]

You can extract an axum::http::Uri which has all the details.

However I believe there are some limitations with Uri::scheme and HTTPS but I'm not exactly sure. I think the easiest way is to set some configuration that tells the server if its running on HTTP or HTTPS. I suppose you know that when you start the server.

[ttys3]

all the behavior is document in https://www.rfc-editor.org/rfc/rfc7230#section-5.3

There are four distinct formats for the request-target,
depending on both the method being requested and whether the request
is to a proxy.

     request-target = origin-form
                    / absolute-form
                    / authority-form
                    / asterisk-form

[5.3.1](https://www.rfc-editor.org/rfc/rfc7230#section-5.3.1).  origin-form

   The most common form of request-target is the origin-form.

     origin-form    = absolute-path [ "?" query ]

   When making a request directly to an origin server, other than a
   CONNECT or server-wide OPTIONS request (as detailed below), a client
   MUST send only the absolute path and query components of the target
   URI as the request-target.  If the target URI's path component is
   empty, the client MUST send "/" as the path within the origin-form of
   request-target.  A Host header field is also sent, as defined in
   [Section 5.4](https://www.rfc-editor.org/rfc/rfc7230#section-5.4).



[5.3.2](https://www.rfc-editor.org/rfc/rfc7230#section-5.3.2).  absolute-form

   When making a request to a proxy, other than a CONNECT or server-wide
   OPTIONS request (as detailed below), a client MUST send the target
   URI in absolute-form as the request-target.

     absolute-form  = absolute-URI

   The proxy is requested to either service that request from a valid
   cache, if possible, or make the same request on the client's behalf
   to either the next inbound proxy server or directly to the origin
   server indicated by the request-target.  Requirements on such
   "forwarding" of messages are defined in [Section 5.7](https://www.rfc-editor.org/rfc/rfc7230#section-5.7).

   An example absolute-form of request-line would be:

     GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1

you will only get scheme and authority when the client send a absolute-form request.

[LukeAbby]

hmmm, that seems limiting. I guess you're saying it's an intrinsic problem? I know Axum has websocket extractor but I couldn't figure out whether to proxy to ws or wss and scheme seemed like a good way. I'm sure there's other uses for like http versus https. I'm not sure how many other schemes are relevant or even possible for Axum.

[davidpdrsn]

I guess you're saying it's an intrinsic problem?

Yes.

[Pzixel]

I wonder if it's truly an inherent problem. Actix have no problems providing this info:

use actix_web::{web, App, Responder, HttpServer, HttpRequest};

async fn handler(req: HttpRequest) -> impl Responder {
    format!("Requested path: {:?} {}", req.connection_info(), req.uri())
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| App::new()
        .default_service(web::to(handler))
        )
        .bind(("127.0.0.1", 8080))?
        .run()
        .await
}

connection_info provide more detailed request info, including request schema. Response example for request with no headers:

> curl http://localhost:8080/123/456
< Requested path: ConnectionInfo { host: "localhost:8080", scheme: "http", peer_addr: Some("127.0.0.1"), realip_remote_addr: None } /123/456

Do you think it's not possible to do something similar in axum?

[davidpdrsn]

You're welcome to take a stab at implementing something similar. axum just forwards the data directly from the request its gets from hyper.