client-server model

components

CONNECTORS

• Network protocols
• Examples:
  • HTTP/HTTPS
  • TCP

constraints

• Many clients contact one server

• Server does not know identity of client

• Clients do not talk to clients

qualities yielded

• Centralization: computation focused on the server

• Evaluability and maintainability: change one server, impact many clients

• Efficiency impacts: bandwidth limitations

• Reliability impacts: server is single point of failure

rest

• Stands for Representational State Transfer
• The World Wide Web is mostly based on REST architecture

Components

• Web services containing resources
• Resource providers

Connectors

• Primarily application level network protocols, HTTP and HTTPS

Constraints

• Client-server
• Stateless
• Cacheable
• Uniform Interface
• Layered system
• Code on demand (optional)

constraint: Uniform interface

HTTP Verbs: GET, POST, PUT, PATCH, DELETE, OPTION

qualities yielded

• Scalability
• Efficiency
• Decoupling

ajax

• Stands for Asynchronous JavaScript And XML
• It allows us to dynamically fetch data and display it on page without refreshing the page
• It not a programming language; it is a technique

xmlhttpRequest

• An object for exchanging data between client and server behind the scenes
• All browsers provide this object
• Demo: https://www.w3schools.com/js/tryit.asp?filename=tryjs_ajax_first

fetch api

• XMLHttpRequest is complicated, so let's create a abstract wrapper that encapsulates its complexity