introduction to web (techie side)
Post on 17-Oct-2014
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DESCRIPTION
A very insightful presentation by Nick McGrath about a technical introduction to websites. It explains how a website works and where it lives.TRANSCRIPT
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
• It’s 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
• Let’s be serious though, we all know what a website is. We’ve 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 we’re looking for?
• With all these computers and all this information available on the www wouldn’t it be great if there was a uniformed way of locating all the resources we’re 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 doesn’t 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
• It’s 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 swf’s… 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 we’ve seen so far is built by Keong or a bunch of people like him
• And if web sites / pages never changed I’d 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, it’s usually coupled with one or more databases (or databi if you want to impress)
What is a Database?
• Think of Dom’s 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