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Web Application Concepts. Refresh. What is a server? What is a Client How does the Internet work?. Server Client Model. Servers- Wait for requests from clients - Sends requested data to client - May have to communicate with other servers Client- Sends requests to server
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Refresh • What is a server? • What is a Client • How does the Internet work?
Server Client Model • Servers- Wait for requests from clients - Sends requested data to client - May have to communicate with other servers • Client- Sends requests to server -Waits and receives reply from server -Can connect to a small number of servers at any one time
How do clients make request to a server • Applications/ programs- e.g. printer software needs updating the software will request from a server whether there is an update. If so can I have it.
What about the internet? • Same relationship • Program being a web browser is the client • You load the web browser and the browser requests from a server your home page. It may have to get the information from another server across the globe.
We have two sides of a coin- Client and Server • We have to plan our code differently for each side of the coin. • Coding at the Server end • Coding at the Client end • Summary- Which code runs on what machine. Server or Client? So what is a web browser- server or client coding?
Coding at the server end • Server builds web pages. For the client to then view. (all the hard work done by the server) • The server also needs to process inputs from the client. E.g. YouTube pausing video • A server can also act as a form of permanent storage e.g. databases • Server side languages PHP, python and Ruby.
Coding at the client end • The hard work is down by the client (most often the web browser via plugins) • Code is sent by the server and the client creates the builds it. • Needs to makes sure client is able to run code that is sent. Does it need a plugin update? etc. • Can interact with local storage e.g. cookies • Programming is normally in JavaScript as well as HTML and CSS.
There is a new sheriff in townWeb Applications! • You no longer need to have a application stored on your PC to do the work. • Server side coding • Application accessed through the internet via web-browser • Examples- Google Docs, iCloud, Deezer, Gmail, Angry birds(web app) Did you know about Chrome Books. These are Laptops that mainly use web apps.
Questions from me? • Summaries the client server model. • How do we access the internet? • Brief outline of client and server side scripting