Varnish configuration, purge only for basic auth users

purge-auth.vcl

# Varnish configuration 
# Purge only for basic auth users

## HOW TO PURGE

### with browser 
#  1 - Set basic auth on /auth (or change the rule)
#  2 - Authenticate on /auth, and load url to refresh (purge) cache.

### with wget
# wget -r -l1 --http-user=foo --http-password=bar  --auth-no-challenge http://url-to-purge

vcl 4.0;

# Default backend definition.
backend default {
    .host = "127.0.0.1";
    .port = "3005";
}


sub vcl_recv {
    
    # Basic auth end point
    if( req.url == "/auth" ){
        return(pass);
    }

    if (req.http.Authorization){
        # Basic auth user:pass in base64
        # echo -n user:pass | base64
        if (req.http.Authorization ~ "Basic Zm9vOmJhcg=="){ // foo:bar
            unset req.http.Authorization;
            return (purge);
        }
    unset req.http.Authorization; 
    return (hash);
    }
}


sub vcl_backend_response {
    set beresp.ttl = 1y;
}

sub vcl_purge {
    set req.method = "GET";
    return (restart);
}

sub vcl_hit {
   
   if (obj.ttl >= 0s) {
       // A pure unadultered hit, deliver it
       return (deliver);
   }
   if (obj.ttl + obj.grace > 0s) {
       // Object is in grace, deliver it
       // Automatically triggers a background fetch
       return (deliver);
   }
   // fetch & deliver once we get the result
   return (fetch);
}