Add Host extractor

axum/src/extract/host.rs

@@ -1,28 +1,33 @@
-use super::{FromRequest, RequestParts};
+use super::{FromRequest, RequestParts, rejection::{HostRejection, FailedToResolveHost}};
 use async_trait::async_trait;
-use std::{convert::Infallible};
 
 /// Extractor that extracts the host from a request.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub struct Host(pub String);
 
 #[async_trait]
 impl<B> FromRequest<B> for Host
 where
     B: Send,
 {
-    type Rejection = Infallible;
+    type Rejection = HostRejection;
 
     async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
-        if let Some(host) = req.uri().host() {
-            return Ok(Host(host.to_string()));
+        // todo: extract host from http::header::FORWARDED
+
+        if let Some(host) = req.headers().get("X-Forwarded-Host").and_then(|host| host.to_str().ok()) {
+            return Ok(Host(host.to_owned()));
         }
 
-        if let Some(Ok(host)) = req.headers().get("host").map(|host| host.to_str()) {
-            return Ok(Host(host.to_string()));
+        if let Some(host) = req.headers().get(http::header::HOST).and_then(|host| host.to_str().ok()) {
+            return Ok(Host(host.to_owned()));
+        }
+
+        if let Some(host) = req.uri().host() {
+            return Ok(Host(host.to_owned()));
         }
 
-        Ok(Host("".to_string()))
+        Err(HostRejection::FailedToResolveHost(FailedToResolveHost))
     }
 }
 

axum/src/extract/mod.rs

@@ -14,6 +14,7 @@ pub mod ws;
 mod content_length_limit;
 mod raw_query;
 mod request_parts;
+mod host;
 
 #[doc(inline)]
 pub use axum_core::extract::{FromRequest, RequestParts};
@@ -23,13 +24,12 @@ pub use self::{
     connect_info::ConnectInfo,
     content_length_limit::ContentLengthLimit,
     extractor_middleware::extractor_middleware,
+    host::Host,
     path::Path,
     raw_query::RawQuery,
     request_parts::{BodyStream, RawBody},
 };
 
-pub mod host;
-
 #[doc(no_inline)]
 #[cfg(feature = "json")]
 pub use crate::Json;

axum/src/extract/rejection.rs

@@ -65,6 +65,14 @@ define_rejection! {
     pub struct InvalidFormContentType;
 }
 
+define_rejection! {
+    #[status = BAD_REQUEST]
+    #[body = "No host found in request"]
+    /// Rejection type used if the [`Host`](super::Host) extractor is unable to
+    /// resolve a host from it's supplied `RequestParts`.
+    pub struct FailedToResolveHost;
+}
+
 /// Rejection type for extractors that deserialize query strings if the input
 /// couldn't be deserialized into the target type.
 #[derive(Debug)]
@@ -160,6 +168,16 @@ composite_rejection! {
     }
 }
 
+composite_rejection! {
+    /// Rejection used for [`Host`](super::Host).
+    ///
+    /// Contains one variant for each way the [`Host`](super::Host) extractor
+    /// can fail.
+    pub enum HostRejection {
+        FailedToResolveHost,
+    }
+}
+
 #[cfg(feature = "matched-path")]
 define_rejection! {
     #[status = INTERNAL_SERVER_ERROR]