server { listen    80; server_name www.abc.com;	large_client_header_buffers 4 16k;	client_max_body_size 300m;	client_body_buffer_size 128k;	proxy_connect_timeout 600;	proxy_read_timeout 600;	proxy_send_timeout 600;	proxy_buffer_size 64k;	proxy_buffers  4 32k;	proxy_busy_buffers_size 64k;	proxy_temp_file_write_size 64k;	location / { 		default_type application/json;		add_header Content-Type 'text/html; charset=utf-8';		return 200 '{"success":false,"messge":"請升級客戶端"}';	} }