condensing rewrite rules in apache - apache

Question

These are my rewrite rules. The first rule is problematic and its sortof what I'm trying to achieve. The last four work but that's an overkill.
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p(([0-9]{1,5})-([0-9]{1,3}))?$ /test2-$1-$2-$3-$4-$5-$6
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p([0-9]{1,5})-([0-9]{1,3})$ /test-$1-$2-$3-$4-$5-$6
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p([0-9]{1,5})-$ /test-$1-$2-$3-$4-$5
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p([0-9]{1,5})$ /test-$1-$2-$3-$4-$5
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p$ /test-$1-$2-$3-$4
What I'm trying to do is use one rewriterule instead of four to handle URLs in the following formats:
http://example.com/word/####wor##/p#-###
http://example.com/word/####wor##/p#-
http://example.com/word/####wor##/p#
http://example.com/word/####wor##/p
Is there any way I can condense my rewriterules to just one instead of four?
I'll add more info later if necessary.

Answer 1

There might be more elegant ways to solve this, but the following should work:
RewriteRule ^([^/^.]+)/([0-9]{4})([a-z]{3})([0-9]{2})/p(?:([0-9]{1})|([0-9]{1})-|([0-9]{1})-([0-9]{3})){0,1}$ /test-$1-$2-$3-$4-$5-$6-$7-$8 [L,NC]
To break it down:
The first part is what you've been doing so far. It covers capture results $1 to $4.
Then comes /p, which is followed by one big group that's split into several alternations separated with the pipe character |. One of the options contained in this group should match either zero or one time(s) /p(?:...|...|...){0,1}.
The ?: at the beginning of this group signifies that the group as a whole should not be used for capturing as you don't necessarily want to capture the end result (like when it contains an -), so we'll stick to only capturing the sub groups that are relevant. This also means that when counting your capture groups to know which translates to which of your variables ($1, $2 etc.), you will not count this group.
The alternations match the 3 variations you provided for your URLs where the /p is followed by something else:
([0-9]{1})
([0-9]{1})-
([0-9]{1})-([0-9]{3})
Note that in your end result /test-$1-$2-$3-$4-$5-$6-$7-$8 not all variables might match something, depending on the pattern of your URL. Some might remain empty.