Add tls_info / TlsInfo for access to peer's leaf certificate (#1938)

* Add `https_info` / `HttpsInfo` for access to peer's leaf certificate

* Fix blocking API CI failure and add tests

* Fix build failure with feature native-tls

* Skip test_https_info for rustls-tls-manual-roots to fix tests

* Rename HttpsInfo to TlsInfo and move into tls

* Fix formatting

* PR feedback: Remove TlsInfo re-export

src/async_impl/client.rs

@@ -115,6 +115,8 @@ struct Config {
     #[cfg(feature = "__tls")]
     max_tls_version: Option<tls::Version>,
     #[cfg(feature = "__tls")]
+    tls_info: bool,
+    #[cfg(feature = "__tls")]
     tls: TlsBackend,
     http_version_pref: HttpVersionPref,
     http09_responses: bool,
@@ -198,6 +200,8 @@ impl ClientBuilder {
                 #[cfg(feature = "__tls")]
                 max_tls_version: None,
                 #[cfg(feature = "__tls")]
+                tls_info: false,
+                #[cfg(feature = "__tls")]
                 tls: TlsBackend::default(),
                 http_version_pref: HttpVersionPref::All,
                 http09_responses: false,
@@ -408,6 +412,7 @@ impl ClientBuilder {
                         user_agent(&config.headers),
                         config.local_address,
                         config.nodelay,
+                        config.tls_info,
                     )?
                 }
                 #[cfg(feature = "native-tls")]
@@ -418,6 +423,7 @@ impl ClientBuilder {
                     user_agent(&config.headers),
                     config.local_address,
                     config.nodelay,
+                    config.tls_info,
                 ),
                 #[cfg(feature = "__rustls")]
                 TlsBackend::BuiltRustls(conn) => {
@@ -442,6 +448,7 @@ impl ClientBuilder {
                         user_agent(&config.headers),
                         config.local_address,
                         config.nodelay,
+                        config.tls_info,
                     )
                 }
                 #[cfg(feature = "__rustls")]
@@ -586,6 +593,7 @@ impl ClientBuilder {
                         user_agent(&config.headers),
                         config.local_address,
                         config.nodelay,
+                        config.tls_info,
                     )
                 }
                 #[cfg(any(feature = "native-tls", feature = "__rustls",))]
@@ -1483,6 +1491,26 @@ impl ClientBuilder {
         self
     }
 
+    /// Add TLS information as `TlsInfo` extension to responses.
+    ///
+    /// # Optional
+    ///
+    /// This requires the optional `default-tls`, `native-tls`, or `rustls-tls(-...)`
+    /// feature to be enabled.
+    #[cfg(feature = "__tls")]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(
+            feature = "default-tls",
+            feature = "native-tls",
+            feature = "rustls-tls"
+        )))
+    )]
+    pub fn tls_info(mut self, tls_info: bool) -> ClientBuilder {
+        self.config.tls_info = tls_info;
+        self
+    }
+
     /// Enables the [trust-dns](trust_dns_resolver) async resolver instead of a default threadpool using `getaddrinfo`.
     ///
     /// If the `trust-dns` feature is turned on, the default option is enabled.
@@ -1987,6 +2015,8 @@ impl Config {
             }
 
             f.field("tls_sni", &self.tls_sni);
+
+            f.field("tls_info", &self.tls_info);
         }
 
         #[cfg(all(feature = "native-tls-crate", feature = "__rustls"))]

src/blocking/client.rs

@@ -738,6 +738,25 @@ impl ClientBuilder {
         self.with_inner(move |inner| inner.use_rustls_tls())
     }
 
+    /// Add TLS information as `TlsInfo` extension to responses.
+    ///
+    /// # Optional
+    ///
+    /// This requires the optional `default-tls`, `native-tls`, or `rustls-tls(-...)`
+    /// feature to be enabled.
+    #[cfg(feature = "__tls")]
+    #[cfg_attr(
+        docsrs,
+        doc(cfg(any(
+            feature = "default-tls",
+            feature = "native-tls",
+            feature = "rustls-tls"
+        )))
+    )]
+    pub fn tls_info(self, tls_info: bool) -> ClientBuilder {
+        self.with_inner(|inner| inner.tls_info(tls_info))
+    }
+
     /// Use a preconfigured TLS backend.
     ///
     /// If the passed `Any` argument is not a TLS backend that reqwest