Class-19 readings: Readings: Message Queues

Class-19 readings: Readings: Message Queues

Table of Contents

Reading, Research, and Discussion

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

  • Yes and that can be useful because you can send data from server to client and client to server, and you don’t need to establish a TCP connect with 3 way hand shake process for every piece of data you send over.

2. Does socket.io use HTTP? Why?

  • Yes the initial connection is done over HTTP and this socket.io will connect to a HTTP server so it can serve its own client code.

3. What happens when a client emits an event?

  • An object is sent out, for use, on the EventsEmitter global object. It can have several key value pairs, and be custom.

4. What happens when a server emits an event?

  • The client needs to have a listener listening for that event so it can be triggered. socket.on('some event', function(do something here))

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

  • Nothing, the socket receives the event but has no handler to take care of it, so it just does nothing.

6. How can we mitigate this?

  • Always have handlers for the events.

Vocabulary Terms

  • Web Socket :
    • def: A communictions protocol.
  • Socket.io :
    • def: JavaScript Library for realtime web applications.
  • Client :
    • def: Servers provide data and information to clients, a client is a user of a server.
  • Server :
    • def: Severs serve up data, web applications and content so users, clients, can access them.

Additional Resources

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