Mastering Internet of Things

Understanding the Observe pattern

For sensors reporting data regularly and securely, the greatest optimization is the use of the Observe (or Event Subscription) pattern. Using this pattern, the requestor, or subscriber, is only required to send one request, called the subscription. Just as with a normal request, the device returns a response containing the data it wants to return. The difference lies in when the resource changes. When that happens, the device automatically sends a new response to the subscriber, without having to wait for a corresponding request.

Resources that support the Observe pattern are called observable resources. Observing resources is defined in RFC 7641: https://tools.ietf.org/html/rfc7641

In a normal case, this ...