CodeIgniter NGINX Rewrite Rules

server
{
    server_name .example.com;

    access_log /var/log/nginx/example.com.access.log;

    root /var/www/example.com/html;

    index index.php index.html index.htm;

    if ($host ~* ^www\.(.*))
    {
        set $host_without_www $1;
        rewrite ^/(.*)$ $scheme://$host_without_www/$1 permanent;
    }

    if ($request_uri ~* ^(/welcome(/index)?|/index(.php)?)/?$)
    {
        rewrite ^(.*)$ / permanent;
    }

    if ($request_uri ~* index/?$)
    {
        rewrite ^/(.*)/index/?$ /$1 permanent;
    }


    if (!-d $request_filename)
    {
        rewrite ^/(.+)/$ /$1 permanent;
    }


    if ($request_uri ~* ^/system)
    {
        rewrite ^/(.*)$ /index.php?/$1 last;
        break;
    }


    if (!-e $request_filename)
    {
        rewrite ^/(.*)$ /index.php?/$1 last;
        break;
    }

    # catch all
    error_page 404 /index.php;
    # use fastcgi for all php files
    location ~ \.php$
    {
        fastcgi_pass 127.0.0.1:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME /var/www/example.com/html$fastcgi_script_name;
        include fastcgi_params;
    }

    # deny access to apache .htaccess files
    location ~ /\.ht
    {
        deny all;
    }
}