Nginx to rewrite based on a specific argument match

Question

I am trying to achieve a redirection in nginx that should happen only if a specific argument and value pair is existing.

For example : https://www.mywebsite.com/search?abc=453?hjh=7484?foo=bar?joe=blah

should be proxied to an application only if hjh=7484 is present in the request_uri. This can be anywhere in the whole URL, that said its position is not fixed.

If the incoming request against search page doesn't have hjh=7484 the request should be redirected to https://www.mynewwebsite.com/

I have tried putting

    location ~* /search(.*)?hjh=7484(.*)?$ {
    proxy_pass $my_app;
}

Above is ending in 404.

2019/01/21 15:48:47 [error] 113#113: *109 open() "/usr/share/nginx/html/search" failed (2: No such file or directory),

If I change the above regex and allow any requests to search page to be passed its working!

The `location` and `rewrite` directives test a normalized URI which does not include the query string. You need to look at the `$request_uri` or `$args` variable with an `if` or `map` statement. See [this answer](https://serverfault.com/a/930187/316685) for an example. — Richard Smith, Jan 21 '19 at 16:13
I think this is also answered here: https://serverfault.com/questions/811912/can-nginx-location-blocks-match-a-url-query-string — Jaime D, Jan 21 '19 at 16:38

score 1 · Answer 1 · answered Jan 21 '19 at 16:27

1

The location only matches the URI path component. It does not match query strings.

You can check the value of the argument instead, for instance:

location /search {
    if ($arg_hjh = 7484) {
        proxy_pass @my_app;
    }
    # do something else
}

answered Jan 21 '19 at 16:27

Michael Hampton

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Yes I had tried the same and was still ending up in a 404! The config I tried was like ` `location /search { if ($arg_hjh=7484) { proxy_pass $my_app; } }` – Raju Divakaran Jan 21 '19 at 16:42
Have you checked where the 404 is sent from? It is possible that nginx proxies the request forward, but your app cannot find the resource. – Tero Kilkanen Jan 21 '19 at 19:09
@RajuDivakaran What is in the nginx error log? – Michael Hampton Jan 21 '19 at 19:40
I was just getting 404, with error saying `2019/01/21 15:48:47 [error] 113#113: *109 open() "/usr/share/nginx/html/search" failed (2: No such file or directory),` – Raju Divakaran Jan 22 '19 at 09:43

score 0 · Answer 2 · answered Jan 22 '19 at 09:52

I am able to get this working by using the method posted here Can nginx location blocks match a URL query string?

error_page 419 = @searchquery;

if ($args ~ "(^|&)hjh=7484" ) {
    return 419;
}

location @searchquery {
    proxy_pass $my_app;
}

Now the problem is any request with that argument, not only to search page will be processed. What would be the best way to make this restricted only to /search location ?

Nginx to rewrite based on a specific argument match

2 Answers2