CLASS 13

Message Queue

REVIEW, RESEARCH AND DISCUSS

• HOME

What does it mean that web sockets are bidirectional? Why is this useful?

• Bidirectional is a communications mode that is capable of transmitting data in both directions to send and receive, but not at the same time.

Does socket.io use HTTP? Why?

• Yes it can.

What happens when a client emits an event?

• when the client emits an event will get to the listner on the server side and an event is triggered.

What happens when a server emits an event?

• When our server emits events which match the first ‘event’ argument the callback will be run. Inside these callbacks we can take the actions we want on the client-side.

What happens if a client “misses” an event?

• The events will be ignored.

How can we mitigate this?

• you can mitigate this by having event handlers with some kind of logic.

TERMS:

• Socket

• Web Socket

The WebSocket is a way to exchange data between browser and server via a persistent connection. The data can be passed in both directions as “packets”, without breaking the connection and additional HTTP-requests.

• Socket.io

• Socket.IO is a JavaScript library for realtime web applications. It enables realtime, bi-directional communication between web clients and servers. It has two parts: a client-side library that runs in the browser, and a server-side library for Node.js

• client

• A client refers to the program on the user side

• Server

• A server refers to the programm running by the server side to connect to the client.

• OSI Model

• The Open Systems Interconnection model is a conceptual model that characterises and standardises the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology.

• TCP Model

• The Internet protocol suite is the conceptual model and set of communications protocols used in the Internet and similar computer networks. It is commonly known as TCP/IP because the foundational protocols in the suite are the Transmission Control Protocol and the Internet Protocol.

• TCP

• It is one of the most commonly used protocols within digital network communications and ensures end-to-end data delivery.

• UDP

• User Datagram Protocol is a communications protocol that is primarily used for establishing low-latency and loss-tolerating connections between applications on the internet.

• Packets

• Packets carry the data in the protocols that the Internet uses.