Regex plus variable in Nginx `proxy

Nginx proxy_redirect allows the use of variables such as $my_var and regular expressions, prefixed with ~.

But it seems impossible to use them both in combination. Is this possible, and what is the correct syntax for escaping meta-characters?

For example, I've tried:

proxy_redirect ~*https?://\\$proxy_host/(.*)$ /app1/$1
proxy_redirect ~*https?://\$proxy_host/(.*)$ /app1/$1
proxy_redirect ~*https?://$proxy_host/(.*)$ /app1/$1

Obviously the last example is incorrect, as the $ before proxy_host is interpreted as a regex meta character. But the two other examples don't work either. (They aren't recognized and so don't rewrite the Location header.

When I replace with just

proxy_redirect ~*https?://[^/] /(.*)$ /app1/$1

the redirect works just fine.

The issue is that this will redirect even for external redirects, so is too inclusive.

CodePudding user response：

Variables and regular expressions are mutually exclusive.

To match both http and https you could just use two consecutive statements, for example:

proxy_redirect http://$proxy_host/ /app1/;
proxy_redirect https://$proxy_host/ /app1/;

Anything following the matched string is automatically appended to the replacement string, so a regular expression is not necessary needed.