Ask for an nginx rewrite rule

Let's say I'm using a pan-resolved domain name of *.domain.com
Now I want to judge when the domain name is not www.domain.com and satisfies the condition for ([\w]{2,5}). Domain.com's two-level domain name is redirected to www.domain.com/domain.php?domain= ([\w]{ 2,5}) of the rewrite rule.

The first thing I wrote was this:

Set $domain ", if ($hots ~* ([\w]{2,5}). \domain\.com) {    set $domain $;} if ($domain!~" www ") {    rewrite ^ $domain \.domain\.com (. *) $ http://www.domain.com$1?domain= $domain last;}

Then the error is \w for the unsafe match.
And then I changed to:

Set $domain ", if ($hots ~*" ([\w]{2,5}). \domain\.com ") {Set $domain $ A,    } if ($domain! =" www ") {    rewrite ^ $doma In\.domain\.com (. *) $  http://www.domain.com$1?domain= $domain &query_string redirect;}

This time does not have the error, but cannot jump correctly.

So ask me where this code problem is, how should I rewrite it?

Reply to discussion (solution)

Then the error is \w for the unsafe match.
Rewrite [0-9a-za-z] to try this?

In addition, the resolution of the two-level domain name can be added to the PHP portal for more flexible functions.

Change to [0-9a-za-z] is also the same, because before he suggested \w unsafe I changed to this, but also invalid, and then added double quotation marks after the no problem, but the condition seems to judge not satisfied

