Working with URLs
The URL contains a great deal of Internet information in a single string. It tells you the name of the server, the name of the file on the server, any data that you are supplying to generate a dynamic response, and even the protocol to use to retrieve the information. In basic form, URLs look like this:
| http://www.oreilly.com/oreilly/about.html |
This URL has three elements. The first section tells you (or your
software) the protocol in use for this resource. In this case, it is
HTTP, shown by http:. The next
section indicates the server name and its corresponding domain. In this
case the server is named www, and the
domain is oreilly.com, coming
together as //www.oreilly.com. What
follow are a pathname (/oreilly/) and
a filename (about.html). Your browser
uses this information as it comes to the brilliant conclusion to use
HTTP in connecting with www in
oreilly.com, and retrieves the
/oreilly/about.html file.
Of course, URLs can become more complicated. If you type “Python” into a search box and click Submit, your browser may go after a URL similar to the following:
| http://search.oreilly.com/cgi-bin/search?term=Python&category=All&pref=all |
Now there are several more items to examine. First, the server has
changed from www to search. Second, the path has changed from
/oreilly/ to /cgi-bin/. The filename about.html has been replaced with a target
named search. But most interesting is
the question mark and the data that follows:
?term=Python&category=All&pref=all
This portion ...