federation-api: Add third party invite endpoint

ruma-federation-api/CHANGELOG.md

@@ -25,7 +25,10 @@ Improvements:
       create_leave_event::{v1, v2},
       get_leave_event::v1,
   },
-  thirdparty::bind_callback::v1,
+  thirdparty::{
+      bind_callback::v1,
+      exchange_invite::v1,
+  },
   ```
 
 # 0.0.3

ruma-federation-api/src/thirdparty.rs

@@ -1,3 +1,4 @@
 //! Module for dealing with third party identifiers
 
 pub mod bind_callback;
+pub mod exchange_invite;

ruma-federation-api/src/thirdparty/exchange_invite.rs

@@ -0,0 +1,7 @@
+//! The receiving server will verify the partial `m.room.member` event given in the request body.
+//! If valid, the receiving server will issue an invite as per the [Inviting to a room] section
+//! before returning a response to this request.
+//!
+//! [Inviting to a room]: https://matrix.org/docs/spec/server_server/r0.1.4#inviting-to-a-room
+
+pub mod v1;

ruma-federation-api/src/thirdparty/exchange_invite/v1.rs

@@ -0,0 +1,57 @@
+//! [PUT /_matrix/federation/v1/exchange_third_party_invite/{roomId}](https://matrix.org/docs/spec/server_server/r0.1.4#put-matrix-federation-v1-exchange-third-party-invite-roomid)
+
+use ruma_api::ruma_api;
+use ruma_events::{room::member::ThirdPartyInvite, EventType};
+use ruma_identifiers::{RoomId, UserId};
+
+ruma_api! {
+    metadata: {
+        description: "The receiving server will verify the partial m.room.member event given in the request body.",
+        method: PUT,
+        name: "exchange_invite",
+        path: "/_matrix/federation/v1/exchange_third_party_invite/:room_id",
+        rate_limited: false,
+        authentication: AccessToken,
+    }
+
+    request: {
+        /// The room ID to exchange a third party invite in.
+        #[ruma_api(path)]
+        pub room_id: &'a RoomId,
+
+        /// The event type. Must be `m.room.member`.
+        #[serde(rename = "type")]
+        pub kind: EventType,
+
+        /// The user ID of the user who sent the original invite event.
+        pub sender: &'a UserId,
+
+        /// The user ID of the invited user.
+        pub state_key: &'a UserId,
+
+        /// The content of the invite event.
+        pub content: &'a ThirdPartyInvite,
+    }
+
+    #[derive(Default)]
+    response: {}
+}
+
+impl<'a> Request<'a> {
+    /// Creates a new `Request` for a third party invite exchange
+    pub fn new(
+        room_id: &'a RoomId,
+        sender: &'a UserId,
+        state_key: &'a UserId,
+        content: &'a ThirdPartyInvite,
+    ) -> Self {
+        Self { room_id, kind: EventType::RoomMember, sender, state_key, content }
+    }
+}
+
+impl Response {
+    /// Creates a new `Response`.
+    pub fn new() -> Self {
+        Self
+    }
+}