Nuts and Bolts: URL's
INFO 253A: Front end Web Architecture
Kay Ashaolu
URI
Uniform Resource Identifier
http://www.yelp.com/biz/jupiter-berkeley#query:jupiters
URI - URL - URN
URI (Identifier)
Identifies some resource (e.g. person or file)
URL (Location)
Specifies the Location of an identifier
Implies availability
URN (Name)
Specifies the Name of an identifier
Does not imply availability
Example
Full URI
http://www.yelp.com/biz/jupiter-berkeley#query:jupiters
URL Portion
http://www.yelp.com/biz/jupiter-berkeley
URN Portion
www.yelp.com/biz/jupiter-berkeley#query:jupiters
Resource
Any concept you can name or identify
So far, typically files
Also generated pages, like a user profile
Components
http://www.yelp.com/biz/jupiter-berkeley#query:jupiters
Scheme
http
://www.yelp.com/biz/jupiter-berkeley#query:jupiters
Specifies how the rest of the URI is laid out
Typically protocols
Hierarchical
http:
//www.yelp.com/biz/jupiter-berkeley#query:jupiters
"Directions" to the resource through hosts and folders
Domain / Hostname
http://
www.yelp.com
/biz/jupiter-berkeley#query:jupiters
"Site" or machine name
Path
http://www.yelp.com
/biz/jupiter-berkeley#query:jupiters
Similar to directories, but not necessarily linked!
Groups common resources together
Path
Relative
biz/jupiter-berkeley#query:jupiters
Absolute
http://www.yelp.com
/biz/jupiter-berkeley#query:jupiters
Query (Optional)
https://www.google.com/
?q=ischool&ref=class
Starts with ?
key=value pairs, delimited by &
NOTE: This is one way of sending parameters to a server
Port Number
https://www.ischool.berkeley.edu
:443
/index.php
Specifies a port number to connect to
Ports are like doorways to a server
Common ports: 80 for HTTP, 443 for HTTPS
Fragment
http://en.wikipedia.org/wiki/URI_scheme
#Examples
Specify a sub-resource, eg. a section on a page
Browser will jump to element id
Questions