The concept of "Device Shadows" introduced by AWS IoT is great for situations when devices have intermittent connectivity.
However it seems that this requires for the device to subscribe to the messages from the remote "cloud" node (AWS IoT). Seems like for MQTT protocol this is an easy task, as it is kinda "always on" connection between the device and the remote node and the MQTT is meant for actively pushing messages between the two.
However when using HTTP, which opens/closes connection all the time - would I still be able to use device shadows? As it seems that in case of HTTP it would be hard to "subscribe" to messages from the remote node...