export GetSubscriptionTimeout API

Author: tianfeng-yang

src/controller/python/chip/clusters/Attribute.py

@@ -520,6 +520,22 @@ def GetReportingIntervalsSeconds(self) -> Tuple[int, int]:
 
         return minIntervalSec.value, maxIntervalSec.value
 
+    def GetSubscriptionTimeout(self) -> int:
+        '''
+        Returns the timeout after which we consider the subscription to have
+        dropped, if we have received no messages within that amount of time.
+
+        Returns 0 if a subscription has not yet been established (and
+        hence the MaxInterval is not yet known), or if the subscription session
+        is gone and hence the relevant MRP parameters can no longer be determined.
+        '''
+        timeoutMs = ctypes.c_uint32(0)
+        handle = chip.native.GetLibraryHandle()
+        builtins.chipStack.Call(
+            lambda: handle.pychip_ReadClient_GetSubscriptionTimeout(self._readTransaction._pReadClient, ctypes.pointer(timeoutMs))
+        )
+        return timeoutMs.value
+
     def SetResubscriptionAttemptedCallback(self, callback: Callable[[SubscriptionTransaction, int, int], None], isAsync=False):
         '''
         Sets the callback function that gets invoked anytime a re-subscription is attempted. The callback is expected

src/controller/python/chip/clusters/attribute.cpp

@@ -476,6 +476,22 @@ PyChipError pychip_ReadClient_GetReportingIntervals(ReadClient * pReadClient, ui
     return ToPyChipError(err);
 }
 
+void pychip_ReadClient_GetSubscriptionTimeout(ReadClient * pReadClient, uint32_t * milliSec)
+{
+    VerifyOrDie(pReadClient != nullptr);
+
+    Optional<System::Clock::Timeout> duration = pReadClient->GetSubscriptionTimeout();
+
+    // The return value of GetSubscriptionTimeout cannot be 0
+    // so milliSec=0 can be considered as the subscription has been abnormal.
+    *milliSec = 0;
+    if (duration.HasValue())
+    {
+        System::Clock::Milliseconds32 msec = std::chrono::duration_cast<System::Clock::Milliseconds32>(duration.Value());
+        *milliSec                          = msec.count();
+    }
+}
+
 PyChipError pychip_ReadClient_Read(void * appContext, ReadClient ** pReadClient, ReadClientCallback ** pCallback,
                                    DeviceProxy * device, uint8_t * readParamsBuf, void ** attributePathsFromPython,
                                    size_t numAttributePaths, void ** dataversionFiltersFromPython, size_t numDataversionFilters,