better regular expression?

[Vivek]

Hi,

I am trying to construct a regular expression using the re module that
matches for
1. my hostname
2. absolute from the root URLs including just "/"
3. relative URLs.

Basically I want the attern to not match for URLs that are not on my
host.

The following statement satisfies numbers 1 and 2, but not 3:

line =
re.sub(r'(href=")(http[s]?://'+hostname+'[/]?|/)([^"]*?)(")',r'\1\2\3'+sInfo+r'\4',line)

An improvement that also partially satisfies number 3 is

line =
re.sub(r'(href=")(http[s]?://'+hostname+'[/]?|/|[^h][^t][^t][^p][^:][^/][^/])([^"]*?)(")',r'\1\2\3'+sInfo+r'\4',line)

This is not complete because if the relative url is less than seven
characters, than it will not match.

Any suggestions?

Thanx.