UNIFORM Resource LocatoR (URL)
The Uniform Resource Locator (URL) is what you type into a web browser when you are requesting a page from a site. The web pages you browse also have hyperlinks in them and the hyperlinks contain URLs as well. The URL is sent to the web server to tell it which resource you want to view. A URL has a specific structure:
protocol://hostname/path/to/folder/resource.ext
| protocol | The protocol used to contact the server |
| :// | A separator between the protocol name and the resource |
| hostname | this is the fully qualified host name of the web server you wish to communicate
with. A fully qualified host name would be host.domain.tld. where host = name of the host/server domain = Domain the host belongs to tld = The top level domain to which the server's domain belongs to. |
| /path/to/folder | Represents the file path to the folder relative to the web root directory of the HTTP server. The right leaning slash is used as a separator as it would be on a Unix system. All HTTP server paths are relative to the web server's web root directory. |
| resource.ext | The name (with extension) of the actual resource file you are trying to access or retrieve. |
| ? | Indicates information being submitted to the server in the URL part of the HTTP request. This is called a URL-encoded submission. |
| fieldname=value | Indicates that a field with the name 'name' in a web page form equals a certain value. |
| & | Separater character for field-value pairs in URL encoded form submissions. |
Yes, it is perfectly valid to try to connect to telnet://route-server.ip.att.net, which will open a telnet window to a server. Likewise it is also permissible to use ftp://ftp.isi.edu/innotes as that is also a permitted URL. However, your web browser may or may not understand such additional functions.
If you fail to supply the name of a resource then it is up to the server to decide what action to take. Most servers will deliver a default document or allow you to browse the folder if there is no default document.
