how to use a variable inside a nginx "if" regular expression

I have a caching system I need to bypass if the user's name (in a cookie) is found in the $request_uri. I'm trying to do something like this, but can't get the variable to interpolate into the regex. Any suggestions pretty please?

I can set the $me variable just fine from the cookie; I just can't get it to interpolate into the regex.

set $chk == "need"; 
set $me "kevin"; 
if ($uri ~ $me) { set $chk ""; } 
if ($chk == "need") { rewrite ^ /testing }

I've always tried things like this:

if ($uri ~ "by-{$me}") { set $chk 开发者_高级运维""; }

Thanks! -Kevin

It's not exactly what I asked, but I think it'll work for my purposes. I'm still curious how to interpolate a variable inside a nginx PCRE regex if anyone else knows!

set $chk == "need"; 
set $me "kevin"; 
if ($uri ~ /by-([^-]+)/) { set $by $1; }
if ($by = $me) {set $chk "";}

It's possible to incorporate a variable within a regex expression by just putting $ in front of the variable ... no need to do ${}

so I suppose in your case

if ($uri ~ "by-$me") { set $chk ""; }

the regular expression will then be equal to by-kevin

I've had it work like this for a more complex regex rule

where I wanted orgin to match a list of possible domain names

set $domainWhitelist "yahoo\.com|google\.com|foo\.com";
if ($http_origin ~* "https?://([\w-]*\.)*($domainWhitelist)(:\d+)?") {
...
}