https://github.com/digitalocean/nginxconfig.io  这有个点击选择生成 Nginx 配置文件模板的项目，不过功能性比较局限，可以基于这个二次开发。这个项目相比 1.0 已经很不错了

第1种。参考官方文档：

“When buffering is enabled, nginx receives a response from the proxied server as soon as possible, saving it into the buffers set by the proxy_buffer_size and proxy_buffers directives. If the whole response does not fit into memory, a part of it can be saved to a temporary file on the disk. Writing to temporary files is controlled by the proxy_max_temp_file_size and proxy_temp_file_write_size directives.

When buffering is disabled, the response is passed to a client synchronously, immediately as it is received. nginx will not try to read the whole response from the proxied server. The maximum size of the data that nginx can receive from the server at a time is set by the proxy_buffer_size directive.”

可以试试重定向前将uri复制给其他变量。

例如：
set $origin_uri $uri;