Nginx (Perl) regular expression to reroute from a URL to another

Question

I have a wordpress blog where I have a series of posts with their own slugs. Recently I've noticed legitimate 404 errors where people go to mysite.com/my-slug/&somestuff. or mysite.come/my-slug/somestuff. I've no idea where they got 'somestuff' from but I want to be able to prevent that.

I wrote a regex to reroute from mysite.com/my-slug/anything to mysite.com/my-slug/

^/easy-fluffy-american-pancakes/.+

That works just fine. Well almost. As it turns out, my print-friendly view of any post is

^/easy-fluffy-american-pancakes/print/1234

1234 is the post ID. So now, that also gets redirected to the post. How can I exclude print from the redirect?

^/easy-fluffy-american-pancakes/(.+)|(?!print/[0-9]*/)

I can't quite get it to work. Either it doesn't match or I get too many redirects.

Answer 1

Close

^/easy-fluffy-american-pancakes/(?!print/[0-9]).+

Read (?....) as "not followed by...". From the perspective of the outside of the (?....) , (?....) doesn't match anything, so the .+ starts matching immediately after the / .

Answer 2

If you add an end of string check to the negative look ahead, it will also catch print s with trailing garbage. If that's an issue.

print "foo/" =~ m{foo/(?!print/[0-9]+$).+} ? "redirect" : "pass";
pass

print "foo/9ujsdu" =~ m{foo/(?!print/[0-9]+$).+} ? "redirect" : "pass";
redirect

print "foo/print/1234" =~ m{foo/(?!print/[0-9]+$).+} ? "redirect" : "pass";
pass

print "foo/print/1234?o=1" =~ m{foo/(?!print/[0-9]+$).+} ? "redirect" : "pass";
redirect