Use join_room_by_alias in RoomDirectory

This still doesn't actually cause the room to be joined by alias though, so still need to fix that

src/components/structures/RoomDirectory.js

@@ -81,15 +81,15 @@ module.exports = React.createClass({
         // });
     },
 
-    showRoom: function(roomIdOrAlias) {
+    showRoom: function(roomId, roomAlias) {
         // extract the metadata from the publicRooms structure to pass
         // as out-of-band data to view_room, because we get information
         // here that we can't get other than by joining the room in some
         // cases.
         var room;
-        if (roomIdOrAlias[0] == '!') {
+        if (roomId) {
             for (var i = 0; i < this.state.publicRooms.length; ++i) {
-                if (this.state.publicRooms[i].room_id == roomIdOrAlias) {
+                if (this.state.publicRooms[i].room_id == roomId) {
                     room = this.state.publicRooms[i];
                     break;
                 }
@@ -97,14 +97,6 @@ module.exports = React.createClass({
         }
         var oob_data = {};
         if (room) {
-            // pluck the alias out of the room data and use it to join the room, as we cannot
-            // really join rooms by ID (the HS has no way to get candidate servers). However,
-            // we still have to do this for room in the public room list that don't have an alias
-            // since this is currently the only choice.
-            // (Note we don't just pass the room alias to this function: we still want to be able to
-            // look up the oob data for which we need the room id).
-            var alias = room.canonical_alias || (room.aliases ? room.aliases[0] : undefined);
-            if (alias) roomIdOrAlias = alias;
             if (MatrixClientPeg.get().isGuest()) {
                 if (!room.world_readable && !room.guest_can_join) {
                     var NeedToRegisterDialog = sdk.getComponent("dialogs.NeedToRegisterDialog");
@@ -124,14 +116,21 @@ module.exports = React.createClass({
             };
         }
 
-        // XXX: this interface needs to change to officially accept room IDs
+        var payload = {
-        // or aliases, rather than it happening to work if you pass an alias
-        // as room_id
-        dis.dispatch({
-            action: 'view_room',
-            room_id: roomIdOrAlias,
             oob_data: oob_data,
-        });
+        };
+        if (roomAlias) {
+            payload.action = 'view_room_alias';
+            payload.room_alias = roomAlias;
+        } else {
+            // It's not really possible to join Matrix rooms by ID because the HS has no way to know
+            // which servers to start querying. However, there's no other way to join rooms in
+            // this list without aliases at present.
+            payload.action = 'view_room';
+            payload.room_id = roomId;
+        }
+
+        dis.dispatch(payload);
     },
 
     getRows: function(filter) {
@@ -177,7 +176,7 @@ module.exports = React.createClass({
             topic = linkifyString(sanitizeHtml(topic));
 
             rows.unshift(
-                <tr key={ rooms[i].room_id } onClick={self.showRoom.bind(null, rooms[i].room_id)}>
+                <tr key={ rooms[i].room_id } onClick={self.showRoom.bind(null, rooms[i].room_id, alias)}>
                     <td className="mx_RoomDirectory_roomAvatar">
                         <BaseAvatar width={24} height={24} resizeMethod='crop'
                             name={ name } idName={ name }
@@ -206,7 +205,7 @@ module.exports = React.createClass({
         this.forceUpdate();
         this.setState({ roomAlias : this.refs.roomAlias.value })
         if (ev.key == "Enter") {
-            this.showRoom(this.refs.roomAlias.value);
+            this.showRoom(null, this.refs.roomAlias.value);
         }
     },