正则表达式：匹配“ /”。 仅当未以“ / _local /”为前缀时。

Question

I hate regex! My brain just does not work the way regex does. Can someone please help with the following problem I'm trying to solve ?

I have a nginx config file currently blocking all attempts to access system or hidden files for security reasons (ie files beginning with '.') with the below location config :

location ~ \/\. {
  access_log off;
  log_not_found off;
  deny all;
}

However, this also blocks my CouchDB server requests to example.com/db/_local/.XYZ

I want to allow all requests to X/_local/.X but deny all other requests to X/.X .

So my regex has to match all /. but not /_local/. .

Eg

example.com/.secretfile          // deny
example.com/db/_local/.LONGHASH  // allow
example.com/other/.other         // deny

Can anyone RegEx gurus please help out ?

Answer 1

Assumed that Ngninx is fully PCRE-compatible, this should be a solution:

location ~ (?<!\/_local)\/\. {

This uses a “negative look-behind assertion”: (?<!\\/_local) means “not prefixed by /_local ”.

Edit: Escaped forward slashes