Understanding RegEx - SEO Duplication on last term - regex

Question

i have a problem with duplicate pages for SEO on a website i'm trying to fix. www.example.com/category/c1234 loads just the same as www.example.com/category/c1234garbage
I've been reading online and testing the code and so far I narrowed it down to a possible regex problem. I have the following lines
# url rewrites
RewriteCond %{REQUEST_URI} ^/index\.cfm/.+ [NC]
RewriteRule ^/index.cfm/(([^/]+)/?([^/]+)?)/?(.*)? /index.cfm/$4?$2=$3 [NS,NC,QSA,N,E=SESDONE:true]
I added an R in the rule so I could see if it was passing through there and it is and after it passes that the garbage at the end disappears.
Can someone help me understand this and figure out a way to fix it so when you go to www.example.com/category/c1234garbage it redirects to www.example.com/category/c1234
I've been searching online for quite a while now and thought it might be time to post here since I can't seem to find a solution. I'm reading "Mastering Regular Expressions" but it might take take a while for me to find the answers I'm looking for.
I appreciate any help you can give me. Thank you.
EDIT: This is what i have before that
RewriteEngine On
Rewritebase /
# remove trailing index.cfm
RewriteCond %{QUERY_STRING} ^$
RewriteRule ^index.cfm(\?)?$ / [R=301,L]
# remove trailing slash
RewriteCond %{QUERY_STRING} ^$
RewriteRule (.*)/$ /$1 [R=301,L]
# Remove trailing ?
RewriteCond %{THE_REQUEST} \?\ HTTP [NC]
RewriteRule ^/?(index\.cfm)? /? [R=301,L]
# SEF URLs
SetEnv SEF_REQUEST false
RewriteRule ^[a-z\d\-]+/[a-z]\d+/? /index.cfm/$0 [NC,PT,QSA,E=SEF_REQUEST:true]
RequestHeader add SEF-Request %{SEF_REQUEST}e
RewriteCond %{HTTP:SEF_REQUES} ^true$ [NC]
RewriteRule . - [L]
EDIT: I was reading the htaccess again and found this that I don't understand but it might have some connection. It's located at the bottom of the file.
# lowercase the hostname, and set the TLD name to an enviroment variable
RewriteCond ${lowercase:%{SERVER_NAME}|NONE} ^(.+)$
RewriteCond %1 ^[a-z0-9.-]*?[.]{0,1}([a-z0-9-]*?\.[a-z.]{2,6})$
RewriteRule .? - [E=TLDName:%1]

Answer 1

From your description and your code, it sounds like this is the transformation that's happening here:
www.example.com/category/c1234garbage
↓
www.example.com/index.cfm?category=c1234garbage
So the problem, I think, is not your rewriting rules. The problem is how you're handling querystring parameters on the server side. If you have an actual page called index.cfm that's interpreting those parameters, you should tweak the code behind that page to validate them and redirect to /category/c1234 where appropriate.
I think the code in index.cfm is looking at the parameter, checking to see if it starts with something recognizable, and going from there. You need to make it more strict.
Alternatively, you could add another .htaccess rule to parse the c1234garbage part and decide which part is valid, and which part (if any) is garbage. I can't give you a regex for that, though, since I don't know the rules for a valid input in your application.
Edit:
I think I found the problem. This part here:
RewriteRule ^[a-z\d\-]+/[a-z]\d+/? /index.cfm/$0 [NC,PT,QSA,E=SEF_REQUEST:true]
You specify the beginning of the relative URL with ^, but you don't specify that you want it to match all the way to the end. So I think what's happening is that it's taking the part of the string that matches, throwing out everything else, and appending it to /index.cfm/. So it takes only the /category/c1234 part from /category/c1234garbage, because that's the part that matches ^[a-z\d\-]+/[a-z]\d+/?.
You can probably fix this with just a word break:
RewriteRule ^[a-z\d\-]+/[a-z]\d+\b/? /index.cfm/$0 [NC,PT,QSA,E=SEF_REQUEST:true]
If that doesn't work, I'm afraid we've reached the end of my htaccess knowledge. I'm more of a regex guy.
Just BTW, this still seems a little awkward. If I understand this right, part of the URL will still get thrown out if it doeesn't fit your exact pattern. E.g. /category/c1234?abc=123 will lose its querystring parameters. You might want to redesign how your rules are set up.

Answer 2

I partially solved the problem. I added
# Remove garbage from after category
RewriteCond %{REQUEST_URI} [a-z\d\-]+/[a-z]\d+(.+)
RewriteRule ^([a-z\d\-]+/[a-z]\d+)/? $1 [R=301]
on top of the SEF rules. It's doing what i want which is to remove the garbage from the url but it gives me an infinite loop because its redirecting even when the url is clean. Any hints?
EDIT: So i realized that the .+ at the end is matching the numbers as well... How do i change it to match anything other than numbers after the numbers? basically where I have the .+ i need to have a "match any character except for numbers"
EDIT: I finally got it to work with the following code:
# Remove garbage from after category
RewriteCond %{REQUEST_URI} [a-z\d\-]+/[a-z]\d+[A-Za-z-.]+
RewriteRule ^([a-z\d\-]+/[a-z]\d+)/? $1 [R=301]
The (.+) i was using previously was reading the 2nd number (c1234)as being part of the . so it would always pass the the condition as true unless it was something like c1