client-api: Add GET /auth_issuer endpoint from MSC2965

crates/ruma-client-api/CHANGELOG.md

@@ -9,6 +9,8 @@ Breaking changes:
 Improvements:
 
 - Point links to the Matrix 1.9 specification
+- Add the `get_authentication_issuer` endpoint from MSC2965 behind the
+  `unstable-msc2965` feature.
 
 # 0.17.4
 

crates/ruma-client-api/src/discovery.rs

@@ -1,5 +1,7 @@
 //! Server discovery endpoints.
 
 pub mod discover_homeserver;
+#[cfg(feature = "unstable-msc2965")]
+pub mod get_authentication_issuer;
 pub mod get_capabilities;
 pub mod get_supported_versions;

crates/ruma-client-api/src/discovery/get_authentication_issuer.rs

@@ -0,0 +1,49 @@
+//! `GET /_matrix/client/*/auth_issuer`
+//!
+//! Get the OpenID Connect Provider that is trusted by the homeserver.
+
+pub mod msc2965 {
+    //! `MSC2965` ([MSC])
+    //!
+    //! [MSC]: https://github.com/matrix-org/matrix-spec-proposals/pull/2965
+
+    use ruma_common::{
+        api::{request, response, Metadata},
+        metadata,
+    };
+
+    const METADATA: Metadata = metadata! {
+        method: GET,
+        rate_limited: false,
+        authentication: None,
+        history: {
+            unstable => "/_matrix/client/unstable/org.matrix.msc2965/auth_issuer",
+        }
+    };
+
+    /// Request type for the `auth_issuer` endpoint.
+    #[request(error = crate::Error)]
+    #[derive(Default)]
+    pub struct Request {}
+
+    /// Request type for the `auth_issuer` endpoint.
+    #[response(error = crate::Error)]
+    pub struct Response {
+        /// The OpenID Connect Provider that is trusted by the homeserver.
+        pub issuer: String,
+    }
+
+    impl Request {
+        /// Creates a new empty `Request`.
+        pub fn new() -> Self {
+            Self {}
+        }
+    }
+
+    impl Response {
+        /// Creates a new `Response` with the given issuer.
+        pub fn new(issuer: String) -> Self {
+            Self { issuer }
+        }
+    }
+}