Nginx rewrite append a parameter at the end of an url

nginxregex

I need to configure my reverse proxy so that the following parameter will be added at the end of the url: &locale=de-de

This almost works:

rewrite ^(.*)$ $1&locale=de-de break;

However, the problem is that I need to append '&locale=de-de' only if it isn't already there and if there is a '?' in the url…

Can I get some help on formulating the correct regex to do this?

Another question:
Why is the question mark in my url not shown if I use this:
$uri?$args

Or $uri$is_args$args translates the url not encoded and the question mark is show as %3f.

Ideas?

EDIT: It seems that this behaviour exists while using in combination with proxy_pass. In a simple rewrite it works really well.

Best Answer

In rewrite you match against URL's path part only. Which means, $1 will not contain the query string.
By default, Nginx appends original query string to the rewrite replacement.

So, it should be safe to write

rewrite ^(.*)$ $1?locale=de-de break;

In the case you do not want Nginx to append the original query string, simply specify ? in the end of replacement URL:

rewrite ^(.*)$ $1?locale=de-de? break;

Correct way in new versions of nginx

Turn out my first answer to this question was correct at certain time, but it turned into another pitfall - to stay up to date please check Taxing rewrite pitfalls

I have been corrected by many SE users, so the credit goes to them, but more importantly, here is the correct code:

server {
       listen         80;
       server_name    my.domain.com;
       return         301 https://$server_name$request_uri;
}

server {
       listen         443 ssl;
       server_name    my.domain.com;
       # add Strict-Transport-Security to prevent man in the middle attacks
       add_header Strict-Transport-Security "max-age=31536000" always; 

       [....]
}

NGINX Reverse Proxy – URL Rewrite

Any redirect to localhost doesn't make sense from a remote system (e.g. client's Web browser). So the rewrite flags permanent (301) or redirect (302) are not usable in your case.

Please try following setup using a transparent rewrite rule:

location  /foo {
  rewrite /foo/(.*) /$1  break;
  proxy_pass         http://localhost:3200;
  proxy_redirect     off;
  proxy_set_header   Host $host;
}

Use curl -i to test your rewrites. A very subtle change to the rule can cause nginx to perform a redirect.

Best Answer

Related Solutions

NGINX Redirect – How to Rewrite All HTTP Requests to HTTPS While Maintaining Sub-Domain

Correct way in new versions of nginx

NGINX Reverse Proxy – URL Rewrite

Related Topic