introduction to web (techie side)

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Post on 17-Oct-2014

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A very insightful presentation by Nick McGrath about a technical introduction to websites. It explains how a website works and where it lives.

TRANSCRIPT

web101.ppt

How web sites work

An epic story of how rugbyheaven.com.au delivers important news to my screen every

morning

Covering

What is a website and where does it live?

How does our browser find a given website?

How does our browser display a given website?

What is a database and how does it work?

What is the Internet?

The internet is like our office computer network but on a global scale

There are literally millions of computers in this networked together

Simply put the internet is an international network of computers.

What is the World Wide Web?

The www exists on the internet

Its a lose term to define the part of the internet that everyone can see and use

What is a website?

According to the wikipedia a website is a collection of related web pages, images, videos or other digital assets that are addressed with a common domain name

Lets be serious though, we all know what a website is. Weve all been to google.com, wikipedia.org or of course rugbyheaven.com.au

Do websites actually exist in cyberspace?

No!!!

Websites live in specific locations on web servers

How do we find what were looking for?

With all these computers and all this information available on the www wouldnt it be great if there was a uniformed way of locating all the resources were looking for

Introducing the uniformed resource locator or URL for short

http://www.rugbyheaven.com.au/news/200909.html

How does a URL map to a web page?

Domain names are part of a URL (http://www.rugbyheaven.com.au/news/200909.html)

DNS servers map domain names to physical machines

Finally our browser has found our site

Now our computer can open a dialogue between the browser and the web server using the request-response model

Finally a web page

This is what we expect to see on our screen

How does it happen?

A request is made to the server for a single specific file (in this case index.html)

A response is sent back to the browser in the form of HTML

HTML

Our browser reads the HTML and renders it to our screens

Why doesnt it look anything like the web site I know and love??

HTML is very simple

Yes that kind of simple

BUT it does do a couple of things very well

HTML has friends

HTML is very good at displaying text / data and linking to other resources

Links to other resources can be overt or covert

This page has been improved slightly by including cascading style sheets

HTML and Images

Its still not quite right

The Browser now needs to request all the Images from the server too

We request this

It starts like this

Trasforms into this

And finally blossoms into this

Statistics

In the example we just saw there were 64 files downloaded to the browser, they were combinations of css, js, jpg, gif and swfs And it all happened so quickly

A little closer to home, on the PhotoChains homepage there are more than 130 separate files downloaded!!!

So who builds this?

Basically everything weve seen so far is built by Keong or a bunch of people like him

And if web sites / pages never changed Id be out of a job

A little bit of jargon

Server side code versus client side code

So what does server side code do?

Web pages are not all static, in fact most these days are dynamic

Servers run pieces of code to deliver different and more specific responses to the browser

Server side rarely lives alone though, its usually coupled with one or more databases (or databi if you want to impress)

What is a Database?

Think of Doms rolodex, it stores specific information

The databases we use allow us create our own structure

Finally

We now know what a website is and where it physically lives

We also know how our computer finds that website

And finally we know how a webpage gets displayed in our browser

We know what a database is and a bit about how it works

Honourable techies

Thanks for listening, you can all be honourable techies for the day Because deep down I all know you want to be