Notes

Regular Expressions

• Regular Expression is a Pattern-Matching Machine

URLS

• URL : Uniform Resource Locator.
• There are two important acronyms to understanding how the internet works: IETF & RFC.
• IETF : Internet Engineering Task Force.
  • Open standards organization that creates voluntary standards to maintain and improve the usability and interoperability of the Internet.
• RFC : Request for Comments.
  • Document created by programmers, engineers, and scientists in the form of a memorandum.
  • When enough people have reviewed the RFC, the IETF will change it’s status to ‘Internet Standard’ which means that everyone should comply with if they decide to implement the standard.

What is this “resource” thing?

• The term resource is always used in a general sense for whatever might be identified by a URI.
  • Common examples include an electronic document, an aimge or a source of information with a consistnet purpose.

The components of a URL

• The Scheme

  • Used to be called the ‘protocol’.
  • The protocol the browser uses to locate the resource using a Uniform Resource Locator.

• Things between the scheme and authority

  • The characters ‘://’ must exist between the scheme and the authority.
  • Thanks to Sir Tim Berners-Lee.

• The Authority

  • Contains the domain name of the resource that has the resource that you’re trying to access.
  • Sometimes also includes a port number.

• The Path

  • First part of an HTTP request.
  • If a path is omitted from a URl, it is assumed to be ‘/’.

• The Query

  • Extra information sent to the browser meant for the processing of a request.
  • URL encoded key-value pairs with an equal sign between them.
  • Entries are concatenated with ampersand symbol.
  • If a value is not correct is becomes URL encoded with it’s hexadecimal ASCII Code.
• The Fragment
  • Never sent to the server.
  • Tells the browser to access a specific section of the page after it loads.

Reading RFCs

• RFC’s are basically unappealing and technical, not fun to read at all.