CS1999

Foundation CompSci project

You all know some of this already

1

request → response

example page load

Requests and responses

OK, it's more complicated than that

what if page is not there?

2

All computers on the web agree

Request

You know how this works?

No More Kings Sweep the Leg

So here's what you put in your request

• can I get...
• Dominoes
• your home address
• what you want (pizza)
• veggie royale
• extra jalapeños

So here's what you put in your request

• what action
• which supplier
• the return address
• what kind of thing you wanted
• what it was called
• any data to go with that

So here's what you put in your request

• method ("verb")
• authority (host & port)
• your IP address
• accept media types
• path
• arguments/data

All you do with pizza is GET

Clients can choose *methods*

GET is common... but there are others.
Let's have a look!

METHODS

HTTP method to
retrieve data

This is the one you probably use most.

HTTP method to
retrieve no data

GET without the body payload.

You'd do this to see if the pizza delivery network works before investing in an order.

HTTP method to
send data to process

This is the one you've probably used every time you pressed SUBMIT on a form.

You don't do this unless you send ingredients to Dominoes to put on your pizza.

HTTP method to
send data to store

"Hello Dominoes? Could you look after this pizza for me? Ta."

HTTP method to
delete

"Hello Dominoes? Cancel that I've got a burger instead."

HTTP method to
send data for modifying

Updating pizza... I think this analogy has run its course...

Browser URL bar

Right, knowing that, you can see the first half of what a browser does: it creates the request

The URL break-down

Status codes

Status codes

3

Flask

Example

Want a bigger example?