Uniform Resource Identificator (URI)

Two URIdentificator types :  URLocator or URName

see http://www.xfront.com/URLversusURN.pdf

1. URN syntax & examples

   from O'Reilly catalog

   "Uniform Resource Name, the result of an evolving attempt to define a name and address syntax for persistent objects accessible over the Internet; urn:foo:a123,456 is a legal URN consisting of three colon-separated fields: urn followed by a namespace identifier, followed by a namespace specifier (see RFC 1737 and RFC 2141 for details)"

   Example : Oasis names

2. URL syntax & examples

• See first of all RFC1630 T.Berners-Lee June 1994

then RFC1738, RFC1808 and RFC2396 August 1998
a valid URI must be written according to the form scheme:path[?search][#fragmentid]
then : / ? # must be reserved characters, within search string = & , + ; are reserved too
• First example:

  http://us.imdb.com/Name?Montand,+Yves is a valid URL
  

• Second example:

  see http://zazie.enst.fr:8080/exo2.html (ask for its source code)
  enter "10" and "motdepasse" in the two form fields
  and just after go back here striking twice your browser BACK button
  then try
  http://zazie.enst.fr:8080/servlet/ConnectionAuthenticationServlet?PID=10&PASSWD=motdepasse
  this string is a valid URI with a http "scheme"
  

• Next example:

  http://www.google.fr/search?hl=fr&q=define%3A+URL

  reserved or not allowed characters must be writen in "escape" form : %hexhex
  where hexhex stand for the hexadecimal value of an ANSI coded character
  

• More exotic example (not interactive for login authorization reasons) :

  imap://saglio@imap.infres.enst.fr:143/fetch%3EUID%3EINBOX%3E ...
  which stands for
  imap://saglio@imap.infres.enst.fr:143/fetch>UID>INBOX> ...
  

• ...