HyperText Transfer Protocol (HTTP)

If its not HTTP?

It's not web

Simplicity?

Browsers and servers do not need to keep information around between interactions

Although anyone can implement SSL technology, what does certified SSL require?

Certified SSL requires an SSL certificate issued by a so called Certificate Authority (CA) - audited by American Institute of CPAs (AICPA)

400-499

Client request incomplete, file not found, request not allowed

300-399

Client request redirected, action necessary

200-299

Client request successful

HTTP is a so-called stateless protocol. What does this mean?

Each transaction is independent of the previous ones, that is, the process has no memory

What is the certificate used for?

Encryption

Response Code 100-199

General info

What is the latest version of HTTP

HTTP 1.1

SEP?

Somebody Else's problem: ask something/someone else to do the memorizing

How does a server know what its document root is?

Web server configuration file

What is the W3C?

WWW consortium develops open standards to ensure long term growth of the web

What does the certificate guarantee?

that the accessed domain/IP address is under the control of the certificate owner

Where in the five-layer IP stack model can we find HTTP?

The application layer

What does the certificate contain information about?

The certificate owner

Who is Tim Berners-Lee?

The inventor of the World-Wide-Web

How does the five-layer IP stack model explain how the internet works?

Internet does not equal web

What is SSL?

Secure Sockets Layer. Technology establishes safe; for example., encrypted, data exchange

500-599

Server errors

Example of buying a book on the web:

1. Client issues request for information about book X 2. Server replies with price and availability 3. Client issues request to put the book in the shopping cart BUT... HTTP is stateless which means that step 3 is independent of steps 1 and 2. In step 3 the server has no memory about steps 1 and 2, including which book is involved, who you are, etc.

What are the 3 parts to each HTTP client request and each HTTP server response?

1. Request or response line: specifies the contents of the request or the status of the response, respectively. 2. Request or response headers (optional): specify configurations, acceptable formats and lots of other things the browser and the server want to tell each other. For example, the date and time the file was last modified; whether the file may be cached or not, etc. 3. Request or response body (optional): additional data. For example the actual data passed back from the HTTP server or any additional data the server must know in order to execute a request

What are the levels/degrees of certificates?

1. Self-Signed: not issued by CA (mostly used for internal use only) 2. Domain Validated: CA issued: domain/IP address certified 3. Fully Authenticated: CA issued; required background check. ex: is the business operating as a business

Some HTTP is "filtered back" to users through (error) messages in browsers. What is an example of this?

404 Error: File or Directory Not Found

Multistep conversions

Are not stateless. ex: buying a boon on the web or booking a flight

What happens if client is cookie enabled?

Cookie is stored in clients cookie file (persistent)

What is HTTPS?

HTTP with SSL. That is, encrypted HTTP

Cookies?

Store memory client-side

Memory on the go or memory in transit

The server passes all the information back to the client and forgets about the client. But at the next request, the client passes everything it receieved from the server (back) to the server again, plus any new information it wants to submit. we accumulate memory as we carry it back and forth between the client and server the memory is always in transit between the server and client From client to server... it depends on which HTTP method we use

What is HTTP?

a protocol used for data exchange between web clients and web servers

What is Berners-Lee warning us for in his Sci-Am. article "Long Live the Web"?

an article explaining that people are manipulating what the web is for, we are industrially using the web, and people behind the scenes are doing what they want with all the information shared.

What are programs that are invoked by the web server?

browse-edgar, maps, and search... it is these programs task to retrieve or generate the information passed in through the GET or POST and process that information accordingly

Get method

passes parameter=value combinations in the URL

Post method

passes parameter=value combinations of the HTTP client request