Chapter 9: Exploring Network Protocols
Protocols are important to work with devices in a network. To understand the physical layer of network systems, a good start are the Ethernet and Wifi specs
Some important documents to study network protocols are the HTTP 1.1 spec. It will take a while still until HTTP 2.0 becomes main stream, but a good start is FAQ HTTP 2.0.
For developing against an API it can be useful to start with dummy data first.
In Node.js, there are many web servers and you can find overview about Node.js Web Servers here.
The WebSockets protocol (RFC6455)
Enabling real time communication, there is the webSockets protocol.
To work with Websockets in Node.js, you can look at the Websocket stream module.
A nice overview is also the Slides by @theturle32 on WebSockets
WebSockets can also help to enable RPC over web sockets.
Blog post by @substack about modules for web apps
Build your own Arduino weather station