Nginx 实现 location / {} 既能访问 txt

需求背景：

原来的网关入口为 https://testgw.foobar.cn/，也就是说 / 这个 uri 已经 proxy_pass 了后端服务，
现在要在 / 这个 uri 加上微信公众号的js接口安全域名校验文件 MP_verify_7UJT32UzCOGkaUNB.txt，实现能访问 https://testgw.foobar.cn/MP_verify_7UJT32UzCOGkaUNB.txt 这个地址，
那么 nginx 要如何实现访问 / 这个 uri，既能访问到 /MP_verify_7UJT32UzCOGkaUNB.txt，又能 proxy_pass 到后端服务呢？

1、原来的回调网关配置

# cat testgw.foobar.conf
server {
    listen 443;
    server_name testgw.foobar.cn;
    access_log logs/testgw_access.log;
    ssl on;
    ssl_certificate /usr/local/openresty/nginx/conf/cert/foobar.pem;
    ssl_certificate_key /usr/local/openresty/nginx/conf/foobar.key;
    ssl_session_timeout 5m;
    ssl_session_cache shared:SSL:10m;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:HIGH:!aNULL:!MD5:!RC4:!DHE;
    ssl_prefer_server_ciphers on;

    location / {
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-Ip $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://127.0.0.1:8000;
    }
}

2、现在要在 location /｛｝加上校验文件的访问，访问路径为 https://testgw.foobar.cn/MP_verify_7UJT32UzCOGkaUNB.txt，实现的配置如下

# cat testgw.foobar.cn.conf
server {
    listen 443;
    server_name testgw.foobar.cn;
    access_log logs/testgw_access.log;
    ssl on;
    ssl_certificate /usr/local/openresty/nginx/conf/cert/foobar.pem;
    ssl_certificate_key /usr/local/openresty/nginx/conf/cert/foobar.key;
    ssl_session_timeout 5m;
    ssl_session_cache shared:SSL:10m;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:HIGH:!aNULL:!MD5:!RC4:!DHE;
    ssl_prefer_server_ciphers on;
    root /data/wx; # MP_verify_7UJT32UzCOGkaUNB.txt 文件放在了 /data/wx 目录下

    location / {
        # 访问 https://testgw.foobar.cn/MP_verify_7UJT32UzCOGkaUNB.txt 时 --> try_files $uri --> try_files /MP_verify_7UJT32UzCOGkaUNB.txt --> /data/wx/MP_verify_7UJT32UzCOGkaUNB.txt --> 实现了访问
        
        # 访问 https://testgw.foobar.cn/网关转发的uri/xxx 时 --> try_files $uri --> try_files /网关转发的uri/xxx --> /data/wx/网关转发的uri/xxx 不存在 --> try_files @gateway --> location @gateway --> proxy_pass http://127.0.0.1:8000 --> 实现了访问
        try_files $uri @gateway; 
    }
    location @gateway {
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-Ip $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://127.0.0.1:8000;
    }
}

3、实现效果
现在 https://testgw.foobar.cn/MP_verify_7UJT32UzCOGkaUNB.txt 可以访问了，https://testgw.foobar.cn/网关转发的uri/xxx 也可以访问了