http redirect and append client IP as URL query

Question

i have this weird issue which we need as a workaoround for an internal application limitation.

this is what I need, either from haproxy or nginx:

something calls http://my-server/?some=query_string
the server should respond with a redirect (http 301/302) to this location: http://my-other-server/?some=query_string?client_ip=ACTUAL_CLIENT_IP

could somebody provide an idea about how this might work? or even better still - the DNS reverse lookup name for the client IP?

thanks in advance! axel.

You want a second `?` in the query string? That's definitely not normal. — Michael Hampton, Sep 30 '20 at 21:03
Doesn't your other server get the client IP after redirect anyway? — Tero Kilkanen, Oct 01 '20 at 18:37
@MichaelHampton nope, that's a mistake, it should be a "&" of course. — flypenguin, Oct 01 '20 at 22:47
@TeroKilkanen yup, but unfortunately that does not help - like i said it's a workaround for an internal app limitation. I just need to append &client_ip=THING (and again - even better if $THING would be the lookup of the dns *name* of the caller) — flypenguin, Oct 01 '20 at 22:48

score 1 · Answer 1 · answered Oct 01 '20 at 22:59

1

You could try this:

location / {
    return 301 http://my-other-server/?client_ip=$remote_addr&$args;
}

This will assign the IP address. https://github.com/flant/nginx-http-rdns is a reverse DNS lookup module for nginx, which provides $rdns_hostname variable, which you can use instead of $remote_addr. However, you need to compile the module to your nginx to use it.

answered Oct 01 '20 at 22:59

Tero Kilkanen

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Note that doing a DNS lookup here will increase your TTFB by the time it takes to do the lookup. It may or may not be worth doing in real time. It can always be done later. – Michael Hampton Oct 02 '20 at 00:28

http redirect and append client IP as URL query

1 Answers1