NGINX: Redirect a user based on cookie for a specific URL only

Question

I'm building a closed social network and currently when a user is not logged in they will always be redirected to the homepage of my domain.

What I would like to do is do the following:

1. Use NGINX to check if a user is logged in (through checking for a cookie) and then when they go to the homepage (mydomain.com) redirect to to mydomain.com/newsfeed.

2. This check should only be applied when a user brows to the homepage and should not work at ANY other url (or else they would always be redirected).

I'm very new to NGINX and looked at various tutorials for using cookies for redirect but failed to get an answer (most notably to limiting the redirect to only the homepage).

Thanks in advance!

Solution 1

Final correct solution:

location ~* ^/$ {
 if ($http_cookie ~* "wordpress_logged_in") {
    return 301 http://example.com/newsfeed/;
 }
}

Solution 2

Let's pretend I've a cookie like so: name=value

server {
    listen 80;
    server_name mydomain.com;

    location ~* ^/$ {
        if ($cookie_name = "value") {
            return 301 http://example.com/newsfeed/;
        }
    }
}

The location block will only match the homepage, check that the cookie exists (you could also just use if ($cookie_name)), and if present, redirect the user to http://example.com/newsfeed/

Comments

[Mendy]

I wouldn't use 301 since its a permanent redirect, and the redirect you want is only for when logged in. rather use 302.

[Matthew Haworth]

nginx.com/resources/wiki/start/topics/depth/ifisevil Don't use if in a location context

[adriaan]

@MatthewHaworth don't just scream you can't use if inside the location context. The (only) 100% safe things which may be done inside if in a location context are: return ...; and rewrite ... last;. The above example uses return which is totally fine.

[Ivan Shatsky]

Exact match location = / { ... } will be faster than regex location ~ ^/$ { ... }

[Armen Michaeli]

Keep in mind that there is also the $cookie_*name* variable (looking at the use of $http_cookie in the answer).