CoreBluetooth not caching discovered services and characteristics

Question

iOS 6 supposedly caches the discovered services and characteristics of peripherals so that reconnecting to known peripherals is faster. However, it doesn't seem to work in my app.

I save a peripheral after connecting to it, and on the reconnect I call retrievePeripherals with the saved peripheral's UUID. My didRetrievePeripherals gets called and I connect to the peripheral. My didConnectPeripheral gets called and I call discoverServices. I was expecting the services to be returned to my app from the cache. However, the service tables are read from my peripheral.

Because my app is busy reading the service tables, I miss the first measurement sent from the peripheral.

Does anyone know why the cache is not being read? Is there some option I need to set somewhere?

Answer 1

You should try to encrypt the connection. Encrypted connections require pairing and after that, the caching is truly turned on. Plain connections not necessarily trigger the caching mechanism and there is no official statement on this. You should also try iOS beta to see if this has changed there. ;)

The other thing you should consider is optimizing the service discovery. If measurement is very important, then discover the characteristics for that first and once that is done, continue on with the others.