feat(client): add some general HTTP/1 client middleware

Author: seanmonstar

src/client/mod.rs

@@ -7,5 +7,7 @@ pub mod legacy;
 #[cfg(feature = "client-pool")]
 pub mod pool;
 
+pub mod service;
+
 #[cfg(feature = "client-proxy")]
 pub mod proxy;

src/client/service.rs

@@ -0,0 +1,154 @@
+//! Middleware services for normalizing request URIs and Host headers.
+
+use std::task::{Context, Poll};
+
+use http::header::{HeaderValue, HOST};
+use http::{Method, Request, Uri};
+use tower_service::Service;
+
+/// A middleware that ensures the Host header matches the URI's authority.
+///
+/// Particularly useful for HTTP/1 clients and proxies, where the Host
+/// header is mandatory and should be derived from the request URI.
+#[derive(Clone, Debug)]
+pub struct SetHost<S> {
+    inner: S,
+}
+
+/// A middleware that modifies the request target for HTTP/1 semantics.
+///
+/// Ensures CONNECT uses authority-form, and all other methods use origin-form.
+#[derive(Clone, Debug)]
+pub struct Http1RequestTarget<S> {
+    inner: S,
+}
+
+// ===== impl SetHost =====
+
+impl<S> SetHost<S> {
+    /// Create a new `SetHost` middleware wrapping the given service.
+    pub fn new(inner: S) -> Self {
+        SetHost { inner }
+    }
+
+    /// Access the inner service.
+    pub fn inner(&self) -> &S {
+        &self.inner
+    }
+}
+
+impl<S, ReqBody> Service<Request<ReqBody>> for SetHost<S>
+where
+    S: Service<Request<ReqBody>>,
+{
+    type Response = S::Response;
+    type Error = S::Error;
+    type Future = S::Future;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner.poll_ready(cx)
+    }
+
+    fn call(&mut self, mut req: Request<ReqBody>) -> Self::Future {
+        if req.uri().authority().is_some() {
+            let uri = req.uri().clone();
+            req.headers_mut().entry(HOST).or_insert_with(|| {
+                let hostname = uri.host().expect("authority implies host");
+                if let Some(port) = get_non_default_port(&uri) {
+                    let s = format!("{hostname}:{port}");
+                    HeaderValue::from_str(&s)
+                } else {
+                    HeaderValue::from_str(hostname)
+                }
+                .expect("uri host is valid header value")
+            });
+        }
+        self.inner.call(req)
+    }
+}
+
+fn get_non_default_port(uri: &Uri) -> Option<http::uri::Port<&str>> {
+    match (uri.port().map(|p| p.as_u16()), is_schema_secure(uri)) {
+        (Some(443), true) => None,
+        (Some(80), false) => None,
+        _ => uri.port(),
+    }
+}
+
+fn is_schema_secure(uri: &Uri) -> bool {
+    uri.scheme_str()
+        .map(|scheme_str| matches!(scheme_str, "wss" | "https"))
+        .unwrap_or_default()
+}
+
+// ===== impl Http1RequestTarget =====
+
+impl<S> Http1RequestTarget<S> {
+    /// Create a new `Http1RequestTarget` middleware wrapping the given service.
+    pub fn new(inner: S) -> Self {
+        Http1RequestTarget { inner }
+    }
+
+    /// Access the inner service.
+    pub fn inner(&self) -> &S {
+        &self.inner
+    }
+}
+
+impl<S, ReqBody> Service<Request<ReqBody>> for Http1RequestTarget<S>
+where
+    S: Service<Request<ReqBody>>,
+{
+    type Response = S::Response;
+    type Error = S::Error;
+    type Future = S::Future;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner.poll_ready(cx)
+    }
+
+    fn call(&mut self, mut req: Request<ReqBody>) -> Self::Future {
+        // CONNECT always sends authority-form, so check it first...
+        if req.method() == Method::CONNECT {
+            authority_form(req.uri_mut());
+        } else {
+            origin_form(req.uri_mut());
+        }
+        self.inner.call(req)
+    }
+}
+
+fn origin_form(uri: &mut Uri) {
+    let path = match uri.path_and_query() {
+        Some(path) if path.as_str() != "/" => {
+            let mut parts = ::http::uri::Parts::default();
+            parts.path_and_query = Some(path.clone());
+            Uri::from_parts(parts).expect("path is valid uri")
+        }
+        _none_or_just_slash => {
+            debug_assert!(Uri::default() == "/");
+            Uri::default()
+        }
+    };
+    *uri = path
+}
+
+fn authority_form(uri: &mut Uri) {
+    if let Some(path) = uri.path_and_query() {
+        // `https://hyper.rs` would parse with `/` path, don't
+        // annoy people about that...
+        if path != "/" {
+            tracing::debug!("HTTP/1.1 CONNECT request stripping path: {:?}", path);
+        }
+    }
+    *uri = match uri.authority() {
+        Some(auth) => {
+            let mut parts = ::http::uri::Parts::default();
+            parts.authority = Some(auth.clone());
+            Uri::from_parts(parts).expect("authority is valid")
+        }
+        None => {
+            unreachable!("authority_form with relative uri");
+        }
+    };
+}