Readings: Message Queues

• Review, Research, and Discussion

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

• web sockets are bidirectional means it handles both client-side and server-side.
• Whereas HTTP relies on a client request to receive a response from the server for every exchange, WebSockets allow for full-duplex bidirectional communication. This enables the server to send real-time updates asynchronously, without requiring the client to submit a request each time.

2- Does socket.io use HTTP? Why?

• no, Socket.IO is always dependent on a http server

3- What happens when a client emits an event?

• he event gets passed to the server through websockets. Its a tcp connection from the browser to the server. The connection is full duplex meaning the server can send real time data to the client and vise versa.

4- What happens when a server emits an event? -when the server listen to the connection event. When that event is invoked, socket.io pass a socket object to our function. We then listen to all of our sockets for a chat. As defined on the client side, take the data emited from the chat and emit it back to all of our sockets.

5- What happens if a client “misses” an event?

• it stored in queue until the client get opportunity to listen the event. 6- How can we mitigate this? we will push a missed event to the Buffers until it is consumed(used).

Document the following Vocabulary Terms

Term

• Socket
  • a socket is an endpoint of a communication between two programs running on a network. Sockets are used to create a connection between a client program and a server program

• Web Socket

  • The WebSocket object provides the API for creating and managing a WebSocket connection to a server, as well as for sending and receiving data on the connection.
• Socket.io
  • Socket.IO is a library that enables real-time, bidirectional and event-based communication between the browser and the server.
• Client
  • The Clients interface provides access to Client objects.
• Server
  • framework can be used to develop web servers using the ‘http’ module.
• OSI Model
  • The OSI model is an architectural model that represents networking communications.
• TCP Model
  • TCP (Transmission Control Protocol) is a protocol for sending information between computers.
• TCP
  • TCP (Transmission Control Protocol) is a protocol for sending information between computers.
• UDP
  • UDP (User Datagram Protocol) is a long standing protocol used together with IP for sending data when transmission speed and efficiency matter more than security and reliability. -Packets
  • a packet is a small segment of a larger message. Data sent over computer networks*, such as the Internet, is divided into packets.

Preparation Materials

Socket.io Chat example

• Sockets have traditionally been the solution around which most real-time chat systems are architected, providing a bi-directional communication channel between a client and a server
• The server can push messages to clients
• Whenever you write a chat message, the idea is that the server will get it and push it to all other connected clients
• Setup steps here

Rooms and Namespaces

• Room is an arbitrary channel that sockets can join and leave, it can be used to broadcast events to a subset of clients
• Rooms are a server-only concept (client does not have access to the list of rooms it has joined)
• Can join to subscribe the socket to a given channel socket.join()
• Each socket in Socket.io is identified by a random unique identifier (Socket#id), each socket automatically joins a room identified by its own id
• Upon disconnection, sockets leave all the channels they were part of automatically.