identity-service-api: Add public key validity endpoint

ruma-identity-service-api/src/keys.rs

@@ -0,0 +1,3 @@
+//! Endpoints to retrieve, update, and validate keys with an identity server.
+
+pub mod check_public_key_validity;

ruma-identity-service-api/src/keys/check_public_key_validity.rs

@@ -0,0 +1,3 @@
+//! Endpoint to check for valid public key with an identity server.
+
+pub mod v2;

ruma-identity-service-api/src/keys/check_public_key_validity/v2.rs

@@ -0,0 +1,39 @@
+//! [GET /_matrix/identity/v2/pubkey/isvalid](https://matrix.org/docs/spec/identity_service/0.3.0#get-matrix-identity-v2-pubkey-isvalid)
+
+use ruma_api::ruma_api;
+
+ruma_api! {
+    metadata: {
+        description: "Check whether a long-term public key is valid. The response should always be the same, provided the key exists.",
+        method: GET,
+        name: "check_public_key_validity",
+        path: "/_matrix/identity/v2/pubkey/isvalid",
+        authentication: None,
+        rate_limited: false,
+    }
+
+    request: {
+        /// Base64-encoded (no padding) public key to check for validity.
+        #[ruma_api(query)]
+        pub public_key: &'a str,
+    }
+
+    response: {
+        /// Whether the public key is recognised and is currently valid.
+        pub valid: bool,
+    }
+}
+
+impl<'a> Request<'a> {
+    /// Create a `Request` with the given base64-encoded (unpadded) public key.
+    pub fn new(public_key: &'a str) -> Self {
+        Self { public_key }
+    }
+}
+
+impl Response {
+    /// Create a `Response` with the given bool indicating the validity of the public key.
+    pub fn new(valid: bool) -> Self {
+        Self { valid }
+    }
+}

ruma-identity-service-api/src/lib.rs

@@ -1,2 +1,3 @@
 pub mod authentication;
+pub mod keys;
 pub mod status;