Add API endpoint to query current fronters (/s/<hid>/fronters)

src/api_main.py

@@ -80,6 +80,24 @@ class Handlers:
 
         return web.json_response([await s.to_json(hid_getter) for s in switches])
 
+    async def get_system_fronters(request):
+        system_id = request.match_info.get("system")
+        system = await System.get_by_hid(request["conn"], system_id)
+
+        if not system:
+            raise web.HTTPNotFound()
+
+        members, stamp = await utils.get_fronters(request["conn"], system.id)
+        if not stamp:
+            # No switch has been registered at all
+            raise web.HTTPNotFound()
+
+        data = {
+            "timestamp": stamp.isoformat(),
+            "members": [member.to_json() for member in members]
+            }
+        return web.json_response(data)
+
     @require_system
     async def patch_system(request):
         req = await request.json()
@@ -203,6 +221,7 @@ async def run():
         web.get("/s/{system}", Handlers.get_other_system),
         web.get("/s/{system}/members", Handlers.get_system_members),
         web.get("/s/{system}/switches", Handlers.get_system_switches),
+        web.get("/s/{system}/fronters", Handlers.get_system_fronters),
         web.patch("/s", Handlers.patch_system),
         web.get("/m/{member}", Handlers.get_member),
         web.post("/m", Handlers.post_member),