I'm new here, thanks. I'm writing rules for Drupal using the Boost static caching module (like wp-super-cache). Is there anything wrong with using fake error codes like 599, 598 and internal locations to control logic?

[code]
server {
listen 80;
server_name example.com;
access_log /var/log/nginx/example.com.access.log;
error_log /var/log/nginx/example.com.error.log;
root /var/example.com;
index index.php;

if ($host !~* ^(example.com)$ ) { # deny illegal host headers
return 444;
}

location / {
rewrite ^/(.*)/$ /$1 permanent; # remove trailing slashes for SEO
error_page 404 @drupal;

try_files $uri @cache;
}

location @cache {
if ( $request_method !~ GET ) {
return 599;
}
if ($http_cookie ~ "DRUPAL_UID") {
return 599;
}
error_page 599 = @drupal;

expires epoch;
add_header Cache-Control "must-revalidate, post-check=0, pre-check=0";
charset utf-8;

try_files /cache/$host${uri}_$args.html @drupal;
}

location @drupal {
rewrite ^/(.*)$ /index.php?q=$1 last;
}

location ~ \.php$ {
try_files $uri @drupal; #check for existence of php file
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include /etc/nginx/fastcgi_params;
}

location ~ \.css$ {
if ( $request_method !~ GET ) {
return 598;
}
if ($http_cookie ~ "DRUPAL_UID") {
return 598;
}
error_page 598 = @x598;

access_log off;
error_log /dev/null crit; # prevent debugging if compiled --with-debug
expires max; #if using aggregator

try_files /cache/$host${uri}_.css $uri @x404;
}

location ~ \.js$ {
if ( $request_method !~ GET ) {
return 598;
}
if ($http_cookie ~ "DRUPAL_UID") {
return 598;
}
error_page 598 = @x598;

access_log off;
expires max; # if using aggregator

try_files /cache/$host${uri}_.js $uri @x404;
}

location @x598 {
access_log off;
expires max; # max if using aggregator, otherwise sane expire time
}

location ~* ^.+\.(jpg|jpeg|gif|png|ico)$ {
if ($http_referer !~ ^(http://example.com) ) { # prevent image hijacking
return 444;
}

access_log off;
expires 45d;

try_files $uri @x404;
}

location @x404 {
return 404;
}

location ~ /\. {
deny all;
}

location ~* ((cron\.php|settings\.php)|\.(htaccess|engine|inc|info|install|module|profile|pl|po|sh|.*sql|theme|tpl(\.php)?|xtmpl)$|^(Entries.*|Repository|Root|Tag|Template))$ {
deny all;
}
}
[/code]