Web Formats and Protocols

note World Wide Web Standards: url + http + html

Formats and protocols

  • What do those words mean?
    • A convention
    • Gives meaning to “bits on the wire”
    • Example:
  • 3 critical protocols or formats
    • HTTP - Hyptertext Transfer ProtocolP
    • URI - Universal Resource Identifier
    • HTML - Hypertext Markup Language
  • Actually there are a bunch more that are almost as important
    • CSS - Cascading Style Sheets
    • JS (or ECMA) - Javascript
    • More?
  • All this is based on foundational Internet protocols
    • TCP/IP
    • DNS
  • Dissecting the URL
    • Protocol
    • Host Name (see also: domain name, subdomain name)
    • Port (default for http is 80 and for telnet is 23, etc.)
    • Path
    • Parameters
  • HTTP Protocol
    • Client makes a request (a packet is sent)
    • Server Responds to the request (a packet is sent back)
    • URL is on the “envelope” of the request
    • Stateless
  • HTTP Requests contain:
    • Request “method”
    • URL
      • Host name
      • Path
      • Parameters
    • Request Headers
    • Methods:
      • GET, HEAD, POST, PUT, DELETE, a few others
  • HTTP Responses contain
    • Status code
    • Response headers:
      • Content-type
      • Content-length
      • Lots of other stuff