In the previous two chapters, you learned how to use the HTTP protocol to publish your data and to interact with your devices. But HTTP has some limitations when it comes to resource-constrained devices: it is very verbose and consumes a lot of bandwidth compared to the amount of data being transported.
In this chapter, you'll learn how to use the Constrained Application Protocol, or CoAP, to create interfaces for resource-constrained devices, typically devices in networks where bandwidth is an issue. The chapter covers:
- An introduction to the CoAP protocol
- Security in CoAP
- Content encoding in CoAP
- Publishing data using CoAP
- The Observe or Event Subscription communication pattern
- Responding to control actions using CoAP
- Testing your CoAP devices
- Encrypting your CoAP devices
