配置目的： 一个子目录下的代码使用框架，其他部分不采用。
配置如下（仅server段，其他参见nginx文档）：

server { listen 80; server_name localhost.dev; index index.php index.html index.htm i.php; set $root_path '/var/www/'; root $root_path; client_max_body_size 2M; location /backend { # if (-f $request_filename) { break; } rewrite ^/backend/(.*)$ /backend/public/index.php?_url=/$1; } location ~ \.php { fastcgi_buffer_size 128k; fastcgi_buffers 4 256k; fastcgi_busy_buffers_size 256k; fastcgi_pass 127.0.0.1:9000; fastcgi_index /index.php; include fastcgi_params; fastcgi_split_path_info ^(.+\.php)(/.+)$; fastcgi_param PATH_INFO $fastcgi_path_info; fastcgi_param PATH_TRANSLATED $document_root$fastcgi_path_info; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } location ~* ^/(css|img|js|flv|swf|download)/(.+)$ { root $root_path; } location ~ /\.ht { deny all; } }