load balancing - Avoid nginx decoding query parameters on proxy_pass (equivalent to AllowEncodedSlashes NoDecode)

Question

I use nginx as a load balencer in front of several tomcats. In my incoming requests, I have encoded query parameters. But when the request arrives to tomcat, parameters are decoded :

incoming request to nginx:

curl -i "http://server/1.1/json/T;cID=1234;pID=1200;rF=http%3A%2F%2Fwww.google.com%2F"

incoming request to tomcat:

curl -i "http://server/1.1/json/T;cID=1234;pID=1200;rF=http:/www.google.com/"

I don't want my request parameters to be transformed, because in that case my tomcat throws a 405 error.

My nginx configuration is the following :

upstream tracking  {
    server front-01.server.com:8080;
    server front-02.server.com:8080;
    server front-03.server.com:8080;
    server front-04.server.com:8080;
}

server {
    listen 80;
    server_name tracking.server.com;
    access_log /var/log/nginx/tracking-access.log;
    error_log  /var/log/nginx/tracking-error.log;

    location / {
        proxy_pass  http://tracking/webapp;
    }
}

In my current apache load balancer configuration, I have the AllowEncodedSlashes directive that preserves my encoded parameters:

AllowEncodedSlashes NoDecode

I need to move from apache to nginx.

My question is quite the opposite from this question : Avoid nginx escaping query parameters on proxy_pass

Answer 1

I finally found the solution: I need to pass $request_uri parameter :

location / {
    proxy_pass  http://tracking/webapp$request_uri;
}

That way, characters that were encoded in the original request will not be decoded, i.e. will be passed as-is to the proxied server.