fix: don't always query aliases of appservices

only do so if the alias matches the regex in the registration file

src/client_server/alias.rs

@@ -1,5 +1,6 @@
 use super::State;
 use crate::{ConduitResult, Database, Error, Ruma};
+use regex::Regex;
 use ruma::{
     api::{
         appservice,
@@ -86,7 +87,15 @@ pub async fn get_alias_helper(
         Some(r) => room_id = Some(r),
         None => {
             for (_id, registration) in db.appservice.iter_all().filter_map(|r| r.ok()) {
-                if db
+                let aliases = registration
+                    .get("namespaces")
+                    .and_then(|ns| ns.get("aliases"))
+                    .and_then(|users| users.get("regex"))
+                    .and_then(|regex| regex.as_str())
+                    .and_then(|regex| Regex::new(regex).ok());
+
+                if aliases.map_or(false, |aliases| aliases.is_match(room_alias.as_str()))
+                    && db
                         .sending
                         .send_appservice_request(
                             &db.globals,