Client server model: Be familiar with the client server model. Client sends a request message to server, server responds to request by replying with a response message to client. Be familiar with the Websocket protocol and know why it is used and where it is used. The Websocket specification defines an API (Application Programming Interface) establishing a full-duplex 'socket' connection between a web browser and a server over TCP. This means that there is a persistent connection between client and server, allowing both parties to send data at any time. Be familiar with the principles of Web CRUD Applications and REST: • CRUD is an acronym for: • C – Create • R – Retrieve • U – Update • D – Delete. • REST enables CRUD to be mapped to database functions (SQL) as follows: • GET → SELECT • POST → INSERT • DELETE → DELETE • PUT → UPDATE. Students should understand the principles: • database connected to browser using REST – Representational State Transfer - which relies on HTTP request methods • REST allows JavaScript to talk to server through HTTP • REST API (Application Programming Interface) created and run on server, browser Javascript calls API • JSON (JavaScript Object Notation) or XML can be used to transmit data between a server and web application • Javascript referenced by HTML file, eg index.html, is run in browser. Compare JSON (Java script object notation) with XML. JSON compared with XML is: • easier for a human to read • more compact • easier to create • easier for computers to parse and therefore quicker to parse.

Quick explanation

Client server model: Be familiar with the client server model. Client sends a request message to server, server responds to request by replying with a response message to client. Be familiar with the Websocket protocol and know why it is used and where it is used. The Websocket specification defines an API (Application Programming Interface) establishing a full-duplex 'socket' connection between a web browser and a server over TCP. This means that there is a persistent connection between client and server, allowing both parties to send data at any time. Be familiar with the principles of Web CRUD Applications and REST: • CRUD is an acronym for: • C – Create • R – Retrieve • U – Update • D – Delete. • REST enables CRUD to be mapped to database functions (SQL) as follows: • GET → SELECT • POST → INSERT • DELETE → DELETE • PUT → UPDATE. Students should understand the principles: • database connected to browser using REST – Representational State Transfer - which relies on HTTP request methods • REST allows JavaScript to talk to server through HTTP • REST API (Application Programming Interface) created and run on server, browser Javascript calls API • JSON (JavaScript Object Notation) or XML can be used to transmit data between a server and web application • Javascript referenced by HTML file, eg index.html, is run in browser. Compare JSON (Java script object notation) with XML. JSON compared with XML is: • easier for a human to read • more compact • easier to create • easier for computers to parse and therefore quicker to parse

• This point belongs to The Transmission Control Protocol/Internet Protocol (TCP/IP), especially Client server model.
• You need to be able to client server model: Be familiar with the client server model. Client sends a request message to server, server responds to request by replying with a response message to client. Be familiar with the Websocket protocol and know why it is used and where it is used. The Websocket specification defines an API (Application Programming Interface) establishing a full-duplex 'socket' connection between a web browser and a server over TCP. This means that there is a persistent connection between client and server, allowing both parties to send data at any time. Be familiar with the principles of Web CRUD Applications and REST: • CRUD is an acronym for: • C – Create • R – Retrieve • U – Update • D – Delete. • REST enables CRUD to be mapped to database functions (SQL) as follows: • GET → SELECT • POST → INSERT • DELETE → DELETE • PUT → UPDATE. Students should understand the principles: • database connected to browser using REST – Representational State Transfer - which relies on HTTP request methods • REST allows JavaScript to talk to server through HTTP • REST API (Application Programming Interface) created and run on server, browser Javascript calls API • JSON (JavaScript Object Notation) or XML can be used to transmit data between a server and web application • Javascript referenced by HTML file, eg index.html, is run in browser. Compare JSON (Java script object notation) with XML. JSON compared with XML is: • easier for a human to read • more compact • easier to create • easier for computers to parse and therefore quicker to parse.
• Use the linked flashcards and practice questions to check recall, then practise applying the idea in an exam-style answer.