Score:1

Server

Prevent Nginx regex rule to override another rule

RabidTunes

6/2/23, 10:47 PM

I have a Nginx server acting as a reverse proxy for a couple services, the config is similar to this one

location /backend/service1 {
        proxy_pass http://pathto/service1;
}

location / {
        root /a/folder
}

location ~* (\.js|\.css)$
        expires 8d;

        root /home/files/abc/bcd;
}

My problem here is that recently the service1 from backend has to serve a couple static files like /backend/service1/something/file1.js or /backend/service1/something/style.css and the second location, since it's a regex location rule, overrides the first one

All static files provided by backend/service1 have a certain prefix (something), so I tried to improve the regex from the second location to have negative lookahead/lookbehind, but it doesn't seem to work, probably because the main pattern has to have a fixed length (this is what i tried without luck)

location /backend/service1 {
        proxy_pass http://pathto/service1;
}

location / {
        root /a/folder
}

location ~* (?<!something)(.*)(\.js|\.css)$
        expires 8d;

        root /home/files/abc/bcd;
}

How can I achieve this?

0 + 0

configuration

nginx

AlexD

6/3/23, 7:10 AM

https://nginx.org/en/docs/http/ngx_http_core_module.html#location

RabidTunes

6/3/23, 4:27 PM

I already checked the docs, but after checking it for the third time I came to a solution, see my answer below, so thanks I guess

Score:3

Server

Richard Smith

6/3/23, 9:34 AM

If "something" immediately follows /backend/service1, you can add another more specific location that takes precedence over regex locations:

location /backend/service1 {
    proxy_pass http://pathto/service1;
}  
location ^~ /backend/service1/something/ {
    proxy_pass http://pathto/service1/something/;
}  
location ~* \.(js|css)$ { ... }

If the "something" is embedded anywhere in the URL, you will need to use a regular expression, possibly with the notorious negative lookahead. By trial and error, I found a working expression:

location ~* ^(?!.*something).*\.(js|css)$ { ... }

0 + 0

Score:0

Server

RabidTunes

6/3/23, 4:26 PM

I accepted the other answer, but something that also worked for my case is nesting the location that had the regex. Something like this

location /backend/service1 {
        proxy_pass http://pathto/service1;
}

location / {
        location / {
            root /a/folder
        }

        location ~* (\.js|\.css)$
            expires 8d;

            root /home/files/abc/bcd;
        }
}

This way if the destination URI is prefixed by /backend/service1 the first location will trigger, for any other locations, the / location will trigger and then the regex can take effect

0 + 0

Richard Smith

6/3/23, 5:55 PM

This solution does not answer your question. And is the same as using `location ^~ /backend/service1`

RabidTunes

6/4/23, 7:54 AM

Why do you say that it does not answer my question? I fixed my issue doing this, is it wrong? Will give me issues in the future?

RabidTunes

6/4/23, 8:12 AM

I will try later your solution because it is simpler, and if it works, I will accept your answer in favor of mine, but i actually did fix my issue with my approach, so I don't understand your comment

Richard Smith

6/4/23, 9:54 AM

I am not saying that it does not solve your problem, and its good that you've found a solution that works for you. But the question you posted to SF specifically asked about a certain prefix "something", and this answer does not address that.

RabidTunes

6/4/23, 3:24 PM

Your solution works and it's simpler so I accepted that and I edited this, thanks!

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Prevent Nginx regex rule to override another rule

TH: ป้องกันไม่ให้กฎ Regex ของ Nginx แทนที่กฎอื่น

RO: Împiedicați regula regex Nginx să înlocuiască o altă regulă

RU: Предотвратить правило регулярного выражения Nginx для переопределения другого правила

VI: Ngăn quy tắc regex Nginx ghi đè quy tắc khác

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