Add get_username_availibility endpoint

CHANGELOG.md

@@ -22,6 +22,7 @@ Improvements:
 * Add `r0::capabilities::get_capabilities` (introduced in r0.5.0)
 * Add `r0::keys` endpoints (introduced in r0.3.0)
 * Add `r0::session::get_login_types` (introduced in r0.4.0)
+* Add `r0::account::get_username_availability` (introduced in r0.4.0)
 
 # 0.5.0
 

src/r0/account.rs

@@ -2,6 +2,7 @@
 
 pub mod change_password;
 pub mod deactivate;
+pub mod get_username_availability;
 pub mod register;
 pub mod request_password_change_token;
 pub mod request_register_token;

src/r0/account/get_username_availability.rs

@@ -0,0 +1,26 @@
+//! [GET /_matrix/client/r0/register/available](https://matrix.org/docs/spec/client_server/r0.6.0#get-matrix-client-r0-register-available)
+
+use ruma_api::ruma_api;
+
+ruma_api! {
+    metadata {
+        description: "Checks to see if a username is available, and valid, for the server.",
+        method: GET,
+        name: "get_username_availability",
+        path: "/_matrix/client/r0/register/available",
+        rate_limited: true,
+        requires_authentication: false,
+    }
+
+    request {
+        /// The username to check the availability of.
+        #[ruma_api(query)]
+        pub username: String,
+    }
+
+    response {
+        /// A flag to indicate that the username is available.
+        /// This should always be true when the server replies with 200 OK.
+        pub available: bool
+    }
+}