Nginx直接返回Json

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":"请升级客户端"}';
}
}