multiple root nginx config

server{
set $RELEASE app-dev;
set $PROJECT_PATH /opt/www/sdaminfo;
set $yii_bootstrap index.php;
set $html_root $PROJECT_PATH/wwwroot;

    listen 80;

    include conf.d/application_params;
root $html_root;

location / {
    include       conf.d/sdaminfo_fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $PROJECT_PATH/$RELEASE/php_htdocs/$yii_bootstrap;
    fastcgi_param SCRIPT_NAME /$yii_bootstrap;
}

location ~ \.php$ {
    fastcgi_split_path_info  ^(.+\.php)(.*)$;

    # let yii catch requests to non-existing php files
    set $fsn $PROJECT_PATH/$RELEASE/php_htdocs/$yii_bootstrap;
    if (-f $PROJECT_PATH/$RELEASE/php_htdocs$fastcgi_script_name){
        root  $PROJECT_PATH/$RELEASE/php_htdocs;
        set $fsn $PROJECT_PATH/$RELEASE/php_htdocs$fastcgi_script_name;
    }

    include       conf.d/sdaminfo_fastcgi_params;
    fastcgi_param SCRIPT_FILENAME   $fsn;
    fastcgi_param SCRIPT_NAME       $fastcgi_script_name;
    fastcgi_param PATH_TRANSLATED   $fsn;
}

location ~ ^/(images|js|css)/ {
    expires  90d;
    root $PROJECT_PATH/$RELEASE/static_htdocs;
}

location ~ ^/(assets|files) {
    root $html_root;
}

location /fancybox/ {
    root $PROJECT_PATH/$RELEASE/static_htdocs/js;
}

    location = /sitemap.xml {
        alias $html_root/sdaminfo.sitemap.xml;
    }

    location = /robots.txt {
        alias $PROJECT_PATH/$RELEASE/static_htdocs/robots/sdaminfo.robots.txt;
    }
}