Nginx: Remove Single Query String parameter

Question

I have a server that returns a 301 HTTP redirect url which contains an API key. The redirect hits Nginx and in there I need to add an Authorization HTTP Header that contains the value of the API key. I want to then remove the API key from the query parameters that get sent through

I need to translate /google/?search=abcde&apikey=1234&version=1 to /google/?search=abcde&version=1

Code

location /google/ {
    proxy_set_header    X-Real-IP           $remote_addr;
    proxy_set_header    Host                $http_host;
    proxy_set_header    Authorization       "Bearer $arg_apikey";
    proxy_pass          https://google.com/;
}

I have tried the following, but it doesn't work: Remove parameters within nginx rewrite

location /google/ {
    if ($query_string ~ "^(.*)apikey=(.*)$") {
       rewrite ^(.*)$ $uri? permanent;
    }
    proxy_set_header    X-Real-IP           $remote_addr;
    proxy_set_header    Host                $http_host;
    proxy_set_header    Authorization       "Bearer $arg_apikey";
    proxy_pass          https://google.com/;
}

Any help would be greatly appreciated!

I am not clear on what you are trying to do. Your if block removes the entire query string with a 301 redirect. Are you trying to surgically remove the apikey=1234 part only, and them send the remaining URI upstream with the proxy_pass? — Richard Smith
– Richard Smith, Commented Jul 23, 2020 at 13:06

Richard Smith · Accepted Answer · 2020-07-23 13:43:50Z

7

One solution is to apply a regular expression to the $request_uri variable (which contains the original request including query string) and capture everything before and after the parameter to be removed.

For example:

map $request_uri $newuri {
    default                                   $request_uri;
    ~^(?<prefix>.*)apikey=[^&]+(?<suffix>.*)$ $prefix$suffix;
}
server {
    ...
    location /google/ {
        resolver ...;
        proxy_set_header    X-Real-IP           $remote_addr;
        proxy_set_header    Host                $http_host;
        proxy_set_header    Authorization       "Bearer $arg_apikey";
        proxy_pass          https://google.com$newuri;
    }
    ...
}

You could probably achieve a similar result with an if block. In this example, the proxy_pass statement is constructed using a map variable. See this document for details.

You will probably need to define a resolver because of the variable in the proxy_pass statement. See this document for details.

answered Jul 23, 2020 at 13:43

Richard Smith

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1 Comment

Werner Raath Over a year ago

Great, the moment I've got this sorted and working I'll mark this as the answer

John Pick · Accepted Answer · 2021-12-01 00:24:52Z

0

Use this:

if ($args ~ (.*)&(apikey=[^&]*)(?=&|$)(.*)|^(apikey=[^&]*)(&|$)(.*)) {
    set $args $1$3$6;
    rewrite ^ $uri permanent;
}

in place of your:

if ($query_string ~ "^(.*)apikey=(.*)$") {
       rewrite ^(.*)$ $uri? permanent;
}

answered Dec 1, 2021 at 0:24

John Pick

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Comments

Russell · Accepted Answer · 2024-06-27 16:54:50Z

0

The answer above got me most of the way but left some unwanted & and ? chars in the proxied URL. The solution I came up with was:

 map $request_uri $newuri {
    default $request_uri; # param not found
    ~^(?<prefix>.*)\?apiKey=[^&]+$ $prefix; # param is only param
    ~^(?<prefix>.*)apiKey=[^&]+\&(?<suffix>.*)$ $prefix$suffix; # param not last param
    ~^(?<prefix>.*)\&apiKey=[^&]+$ $prefix; # param is last param
}

answered Jun 27, 2024 at 16:54

Russell

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