fix: prevent thundering-herd of concurrent Syncthing REST API calls

clipsync/pairing.py

@@ -16,6 +16,7 @@
 from collections.abc import Callable
 
 import qrcode
+import requests
 from PIL import Image
 
 from . import config
@@ -174,6 +175,8 @@ def _run(self) -> None:
         while not self._stop.is_set():
             try:
                 self._tick()
+            except requests.RequestException as exc:
+                log.warning("Pending device watcher: Syncthing not responding (%s)", exc)
             except Exception:
                 log.exception("Error in pending device watcher")
             if self._stop.wait(self._interval):

clipsync/syncthing.py

@@ -510,6 +510,7 @@ def __init__(self, api_key: str, base_url: str = config.SYNCTHING_API_URL) -> No
         self._base = base_url.rstrip("/")
         self._session = requests.Session()
         self._session.headers["X-API-Key"] = api_key
+        self._cached_device_id: str | None = None
 
     def _url(self, path: str) -> str:
         return f"{self._base}{path}"
@@ -557,8 +558,10 @@ def wait_until_ready(self, timeout: float = _STARTUP_WAIT) -> bool:
         return False
 
     def get_device_id(self) -> str:
-        status = self._get("/rest/system/status")
-        return status["myID"]
+        if self._cached_device_id is None:
+            status = self._get("/rest/system/status")
+            self._cached_device_id = status["myID"]
+        return self._cached_device_id
 
     def get_config(self) -> dict[str, Any]:
         return self._get("/rest/config")
@@ -646,7 +649,11 @@ def connected_devices(self) -> list[dict[str, Any]]:
         """Return a list of {deviceID, name, connected, address} for paired devices."""
         devices = self.get_devices()
         my_id = self.get_device_id()
-        connections = self.get_connections().get("connections") or {}
+        try:
+            connections = self.get_connections().get("connections") or {}
+        except requests.RequestException:
+            # Connection status is best-effort; don't fail the whole call.
+            connections = {}
         out: list[dict[str, Any]] = []
         for d in devices:
             did = d.get("deviceID")

clipsync/ui.py

@@ -552,6 +552,7 @@ def __init__(
     ) -> None:
         self._win = window
         self._app = app
+        self._refreshing = False
 
         ctk.CTkLabel(container, text="Connected devices", font=ctk.CTkFont(size=18, weight="bold")).pack(pady=(0, 10))
 
@@ -578,7 +579,7 @@ def _exists(self) -> bool:
     def _schedule_refresh(self) -> None:
         if not self._exists():
             return
-        self._win.after(3000, self._auto_refresh)
+        self._win.after(10_000, self._auto_refresh)
 
     def _auto_refresh(self) -> None:
         if not self._exists():
@@ -587,6 +588,9 @@ def _auto_refresh(self) -> None:
         self._schedule_refresh()
 
     def _refresh(self) -> None:
+        if self._refreshing:
+            return
+        self._refreshing = True
         for child in self._list_frame.winfo_children():
             child.destroy()
         ctk.CTkLabel(self._list_frame, text="Loading…", text_color=("gray50", "gray60")).pack(pady=20)
@@ -604,8 +608,11 @@ def _do_refresh(self) -> None:
             error = str(exc)
         if self._exists():
             self._win.after(0, self._apply_refresh, devices, error)
+        else:
+            self._refreshing = False
 
     def _apply_refresh(self, devices: list[dict], error: str | None) -> None:
+        self._refreshing = False
         for child in self._list_frame.winfo_children():
             child.destroy()
         if error:
@@ -1195,6 +1202,7 @@ def __init__(self, parent: ctk.CTk, app: AppContext, on_close: Callable[[], None
         super().__init__(parent, f"{config.APP_NAME} — Incoming Requests", (440, 360), on_close)
         self._app = app
         self._handled: set[str] = set()
+        self._refreshing = False
 
         container = ctk.CTkFrame(self.window, fg_color="transparent")
         container.pack(fill="both", expand=True, padx=20, pady=20)
@@ -1221,7 +1229,7 @@ def __init__(self, parent: ctk.CTk, app: AppContext, on_close: Callable[[], None
     def _schedule_refresh(self) -> None:
         if not self.exists():
             return
-        self.window.after(3000, self._auto_refresh)
+        self.window.after(10_000, self._auto_refresh)
 
     def _auto_refresh(self) -> None:
         if not self.exists():
@@ -1230,6 +1238,9 @@ def _auto_refresh(self) -> None:
         self._schedule_refresh()
 
     def _refresh(self) -> None:
+        if self._refreshing:
+            return
+        self._refreshing = True
         for child in self._list_frame.winfo_children():
             child.destroy()
         ctk.CTkLabel(self._list_frame, text="Loading…", text_color=("gray50", "gray60")).pack(pady=20)
@@ -1247,8 +1258,11 @@ def _do_refresh(self) -> None:
             error = str(exc)
         if self.exists():
             self.window.after(0, self._apply_refresh, pending, error)
+        else:
+            self._refreshing = False
 
     def _apply_refresh(self, pending: dict, error: str | None) -> None:
+        self._refreshing = False
         for child in self._list_frame.winfo_children():
             child.destroy()
         if error: