RewriteRule help

Matching first three characters in filename

[cookie2]

I'm going nuts trying to get this regex for an htaccess rewrite to work. I need to redirect file requests that contain RS= in that order. I've tried:

RewriteRule ^([RS]{2}=)$ http://mydomain.com/index.html

RewriteRule ^([RS=]{3})$ http://mydomain.com/index.html

RewriteRule ^/([RS=]{3})$ http://mydomain.com/index.html

and several others but nothing works. I've googled to see if I could find any better answers on how to match the first three characters in a file name but noting I tried has worked.
Can someone please offer me a suggestion as to what to do or where to look? Thanks.

[wilderness]

explore this

[a-z]{2}

[cookie2]

Thanks for the suggestion but I only want to match the ones that start with RS=. What you show would also match RC or RA etc. and doesn't account for the = sign. I need to match RS= and only RS=.

[wilderness]

^RS=

[g1smd]

Are these in the path part of the URL request or in an attached query string?

Unencoded 'equals' isn't valid in the path part of a URL. It is reserved as the separator between parameter name and parameter value in query strings

[edited by: g1smd at 5:42 am (utc) on Mar 14, 2014]

[lucy24]

I need to redirect file requests that contain RS= in that order. I've tried:

RewriteRule ^([RS]{2}=)

What's with the parentheses and brackets? If you're matching literal text, a simple

^RS=

will do. The form
[RS]{2}
is only necessary if you need to match all of:
RR
RS
SR
SS

You don't need parentheses if you're not capturing for reuse. And you DEFINITELY don't need a closing anchor, since that would only match requests for
"www.example.com/RS="
exactly and that's all.

No leading / slash. That's only for rules lying loose in your config file, and I assume this is happening in htaccess.

(Equals signs in your URLs? Really? I hope you're redirecting in order to get rid of them!)

Oh, and, ahem, the target is

http://www.example.com/

and that's all. No "index.html". I hope you've got the appropriate [R=301,L] flags; hard to tell if that was just a selective cut-and-paste.

Edit: The body of your post said "contain" but the subject header said "first three characters" so I assumed that was what you meant.

Further edit: I'm overlapping with g1. If = signs are flatly forbidden in paths, then obviously there's something more to the question.

[cookie2]

The RS= are in the path. It isn't in my URL. It's part of the filename being requested and I don't know where it's coming from. Example request:
/blogs/myblog/guest_bloggers/RS=^ADAzyT7tVsrGwbLCZ_NFz9.1eROKp8

I want to capture all of those requests that start with RS= and send them to the index page. Yes, this is in htaccess.

[g1smd]

I think an infinite number of redirects to the home page is a bad idea.
You'd be better off blocking access and serving a useful error message.

[cookie2]

But how, g1smd? The string of characters after RS= varies. It's not the same on all requests.

[g1smd]

The RegEx pattern ^RS means "begins with RS".

A RewriteRule with the F or G flag may be useful.

[cookie2]

When I use
RewriteRule ^RS= http://example.com/index.html [R=301,L]
it doesn't match and site shows a 404 page for
/blogs/myblog/guest_bloggers/RS=^ADAzyT7tVsrGwbLCZ_NFz9.1eROKp8

But when I use an online regex generator using only the RS=^ADAzyT7tVsrGwbLCZ_NFz9.1eROKp8 part then it matches. I must be missing something but I don't know what.

[g1smd]

Escape the = sign as \= and add the rest of the path.

RewriteRule ^blogs/myblog/guest_bloggers/RS\= - [G]

[lucy24]

RewriteRule ^RS= http://example.com/index.html [R=301,L]
it doesn't match and site shows a 404 page for
/blogs/myblog/guest_bloggers/RS=^ADAzyT7tVsrGwbLCZ_NFz9.1eROKp8

Well, of course it doesn't match. The pattern says "path must begin with 'RS=' and instead the 'RS=' element comes much further along in the path.

:: lightbulb ::

I think I see the problem. You're thinking of FilesMatch, where you're matching against the name of the file. In mod_rewrite you're matching the entire path, based on where the htaccess is located. To match "filename begins with..." the most universal form would be

(^|/)RS=

If you're not capturing, you don't need to worry about what-if-anything came before the filename. But if the path is always the same (the /blogs/ blahblah part) then spell it out explicitly.

g1, why do equals signs have to be escaped?

[cookie2]

Played around with both of your suggestions. Discovered that if I added to htaccess in /root or /blogs it didn't work. But I tried putting a new htaccess in /blog/myblog and the (^|/)RS= one from Lucy worked.

Thank you both for putting me on the right track. Your help is much appreciated.