HttpsConnector: add tls_server_name to allow overriding TLS handshake

Author: mcluseau

examples/client-tls-server-name.rs

@@ -0,0 +1,40 @@
+//! HTTPS GET client with custome TLS server name based on hyper-tls
+//!
+//! First parameter is the URL to GET.
+//! Second parameter is the TLS server name to negociate.
+use bytes::Bytes;
+use http_body_util::BodyExt;
+
+use http_body_util::Empty;
+use hyper_tls::HttpsConnector;
+use hyper_util::{client::legacy::Client, rt::TokioExecutor};
+use tokio::io::{self, AsyncWriteExt as _};
+
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut args = std::env::args().skip(1);
+
+    let (Some(url), Some(server_name)) = (args.next(), args.next()) else {
+        println!("Usage: client <url> <server_name>");
+        return Ok(());
+    };
+
+    let https = HttpsConnector::new().with_tls_server_name(server_name);
+
+    let client = Client::builder(TokioExecutor::new()).build::<_, Empty<Bytes>>(https);
+
+    let mut res = client.get(url.parse()?).await?;
+
+    println!("Status:\n{}", res.status());
+    println!("Headers:\n{:#?}", res.headers());
+
+    while let Some(frame) = res.body_mut().frame().await {
+        let frame = frame?;
+
+        if let Some(d) = frame.data_ref() {
+            io::stdout().write_all(d).await?;
+        }
+    }
+
+    Ok(())
+}

src/client.rs

@@ -20,6 +20,7 @@ pub struct HttpsConnector<T> {
     force_https: bool,
     http: T,
     tls: TlsConnector,
+    tls_server_name: Option<String>,
 }
 
 impl HttpsConnector<HttpConnector> {
@@ -55,6 +56,15 @@ impl HttpsConnector<HttpConnector> {
         http.enforce_http(false);
         HttpsConnector::from((http, tls))
     }
+
+    /// Get a HttpsConnector with a TLS server name override.
+    ///
+    /// This is useful in cases where you can't work around the URL's host but know the name you
+    /// expect from the remote server's certificate.
+    pub fn with_tls_server_name(mut self, server_name: impl Into<String>) -> Self {
+        self.tls_server_name = Some(server_name.into());
+        self
+    }
 }
 
 impl<T: Default> Default for HttpsConnector<T> {
@@ -98,6 +108,7 @@ impl<T> From<(T, TlsConnector)> for HttpsConnector<T> {
             force_https: false,
             http: args.0,
             tls: args.1,
+            tls_server_name: None,
         }
     }
 }
@@ -137,8 +148,10 @@ where
             return err(ForceHttpsButUriNotHttps.into());
         }
 
-        let host = dst
-            .host()
+        let host = self
+            .tls_server_name
+            .as_deref()
+            .or_else(|| dst.host())
             .unwrap_or("")
             .trim_matches(|c| c == '[' || c == ']')
             .to_owned();