[fractal] API, room: use endpoint in set_room_topic

[Daniel Garcia Moreno <danigm src gnome org>]

commit 62d651fc2927f99ff33b2088677057010531b485
Author: Alejandro Domínguez <adomu net-c com>
Date:   Mon Mar 9 12:51:20 2020 +0100

    API, room: use endpoint in set_room_topic

 fractal-matrix-api/src/backend/mod.rs  |  7 +++++--
 fractal-matrix-api/src/backend/room.rs | 30 ++++++++----------------------
 2 files changed, 13 insertions(+), 24 deletions(-)
---
diff --git a/fractal-matrix-api/src/backend/mod.rs b/fractal-matrix-api/src/backend/mod.rs
index 45d1e091..c1cb6349 100644
--- a/fractal-matrix-api/src/backend/mod.rs
+++ b/fractal-matrix-api/src/backend/mod.rs
@@ -313,8 +313,11 @@ impl Backend {
                 });
             }
             Ok(BKCommand::SetRoomTopic(server, access_token, room_id, topic)) => {
-                let r = room::set_room_topic(self, server, access_token, room_id, topic);
-                bkerror2!(r, tx, BKResponse::SetRoomTopic);
+                thread::spawn(move || {
+                    let query = room::set_room_topic(server, access_token, room_id, topic);
+                    tx.send(BKResponse::SetRoomTopic(query))
+                        .expect_log("Connection closed");
+                });
             }
             Ok(BKCommand::SetRoomAvatar(server, access_token, room_id, fname)) => {
                 let r = room::set_room_avatar(self, server, access_token, room_id, fname);
diff --git a/fractal-matrix-api/src/backend/room.rs b/fractal-matrix-api/src/backend/room.rs
index 3e2e2a58..279a1d77 100644
--- a/fractal-matrix-api/src/backend/room.rs
+++ b/fractal-matrix-api/src/backend/room.rs
@@ -469,38 +469,24 @@ pub fn set_room_name(
 }
 
 pub fn set_room_topic(
-    bk: &Backend,
     base: Url,
     access_token: AccessToken,
     room_id: RoomId,
     topic: String,
 ) -> Result<(), Error> {
-    let url = bk.url(
-        base,
-        &access_token,
-        &format!("rooms/{}/state/m.room.topic", room_id),
-        vec![],
-    )?;
+    let params = CreateStateEventsForKeyParameters { access_token };
 
-    let attrs = json!({
+    let body = json!({
         "topic": topic,
     });
 
-    let tx = bk.tx.clone();
-    put!(
-        url,
-        &attrs,
-        |_| {
-            tx.send(BKResponse::SetRoomTopic(Ok(())))
-                .expect_log("Connection closed");
-        },
-        |err| {
-            tx.send(BKResponse::SetRoomTopic(Err(err)))
-                .expect_log("Connection closed");
-        }
-    );
+    create_state_events_for_key(base, &params, &body, &room_id, "m.room.topic")
+        .map_err(Into::into)
+        .and_then(|request| {
+            let _ = HTTP_CLIENT.get_client()?.execute(request)?;
 
-    Ok(())
+            Ok(())
+        })
 }
 
 pub fn set_room_avatar(