PoC

src/api/client_server/account.rs

@@ -1,5 +1,8 @@
 use super::{DEVICE_ID_LENGTH, SESSION_ID_LENGTH, TOKEN_LENGTH};
-use crate::{api::client_server, services, utils, Error, Result, Ruma};
+use crate::{
+    api::client_server::{self, membership::join_room_by_id_helper},
+    services, utils, Error, Result, Ruma,
+};
 use ruma::{
     api::client::{
         account::{
@@ -287,6 +290,28 @@ pub async fn register_route(body: Ruma<register::v3::Request>) -> Result<registe
                 warn!("Granting {} admin privileges as the first user", user_id);
             }
         }
+
+        let servers = [services().globals.server_name().to_owned()];
+        let join_by_default = services()
+            .globals
+            .join_by_default()
+            .expect("validated on db startup");
+
+        for room_id in join_by_default {
+            join_room_by_id_helper(
+                Some(&user_id),
+                room_id,
+                Some("All men are equal before fish.".to_owned()),
+                &servers,
+                None,
+            )
+            .await
+            .map_err(|e| {
+                tracing::error!("join_by_default: {}", e);
+
+                Error::bad_config("join_by_default.")
+            })?;
+        }
     }
 
     Ok(register::v3::Response {