Transcript 5/10/7

Ian Cutts’ transcript from Chris Wallace taught class 5/10/7 started 22:45 finished 11:30

I am afraid that you'll have to have the notes for this to make any sense at all..

Background Questionnaire :

B)

Get familiar with basics of CSS

Use the class tag

This will individualise your own CSS its CSS’s power!

C)

Protocol host path file port (because it has parameters it indicates the presence of a script)

Classic call to web functions or procedure call

Passing some data to that procedure governed by the parameters set in the url line

Simplest way of making one application or browser get something done

The guts of the web is about passing data

Flat files

By using this structure you can make your program available to anyone in the world! The crux of the web

D)

XML describing

The difference between a tag like subject and the content like nose

The vocabulary is different (unique) – chris created when producing semantic dictionary

Take medical dictionary what is the nose?

The respritory system is composed of the nose

The elemental relationship between different members

XML is a tree structure

But if you draw it out it is a network

Represent graphs

RDF

There must be a set of rules which you make up otherwise someone else could use it

E)

When you develop systems you use get then you can replace with post

Get is debuggable

Post is not saveable suppose you wanted to do the same computation all the time you can save the url! Or bookmark or send it to someone else – it becomes a reusable resource – it could be a button

Post is bad for development and reuse – you can mix post and get

You can bypass the limitations of the form with GET

Currency codes are standard ISO – don’t use sterling internally

The web works with standard codes – and identifiers

If you tell me the currency is in GBP you have used a good standard identifier

Currency rates change in the backend

Lookups to tables happens in the backend

Inside convert.php rates are all to USD as that is a common so to transfer from one obscure currency to another is done by going via USD which keeps the combinations down

H)

Factorial script

Javascript enables you to read and write the current document displayed

Document.data.value.limit is a long way down the tree

Document.write writes out into the current document

Recursion states the next value as some function of the previous version

Factorial 7 = factorial 6 *7

I)

Tricky SQL statement

Trying to convert from one currency and any other

You don’t want to hold all the different rates for 10currencies and 10 rates

What you might do is to use base currencies

There is no traffic over obscure currencies

There is only one table with two different views (aliases)

We want to view the table for both conversions

Different pointers to the table

One is from and the other is to

They point to the same table

It gives two lookups on the same table – it is like a join.

The crux is that you can use a table twice – tricky SQL

The more SQL you know the better!

The world is full of relational databases

SWT

Using socks and http proxy

Concentrate on keeping it local!

GETURLInfo is different program

HEAD is an HTTP method that gets the header

You want to look ahead rather than getting the document

To get the media type

If it’s a particular type of document you might not want to get

To get out through the proxy there is a setting in the compiler

Socket should enable you to set the proxy

Not done in java but has done in php

Low level socket programming

Socket layer to parse proxy addresses

It’s a frequent task

If your going to do any server programming then you need to bypass the firewall

Not being able to do it outside is useless