Turbo_stream_from无法连接Rails预发布环境后端的问题求助

场景说明 #

• Rails 7.1.2应用，视图通过<%= turbo_stream_from session["_csrf_token"] %>订阅会话级Turbo Stream频道（以CSRF Token作为频道名实现会话隔离）
• 控制器动作触发广播逻辑：Turbo::StreamsChannel.broadcast_replace_to session["_csrf_token"], partial: "devise/registrations/creating", target: "registration_new_full_page"，用于注册成功重定向前将表单替换为加载视图

环境差异 #

• 本地开发环境（http://127.0.0.1:3000）：功能完全正常，加载注册页时Rails日志会输出Turbo::StreamsChannel is streaming from [CSRF Token值]，页面HTML中的<turbo-cable-stream-source>标签带有connected=""属性
• 预发布环境：无上述频道流日志，广播的更新无法被页面接收，页面无任何反应；页面HTML中的<turbo-cable-stream-source>标签缺少connected=""属性

预发布环境Nginx代理配置 #

map $http_host $rails {
  myapp.com 123.123.123.123;
  myapp-staging.com 234.234.234.234;
}

...

  location /cable {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-Ssl on; # Optional
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Forwarded-Host $host;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    proxy_set_header X-Real-IP $remote_addr;

    proxy_pass http://$rails;
  }

  location / {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_set_header X-Forwarded-Ssl on; # Optional
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Forwarded-Host $host;
    proxy_set_header X-Real-IP $remote_addr;

    proxy_redirect off;

    proxy_read_timeout 120;
    proxy_connect_timeout 120;
    proxy_send_timeout 120;

    proxy_pass http://$rails;
  }

已排查内容 #

• 浏览器控制台无任何报错信息，Rails和Nginx日志均未记录错误
• 尝试用静态字符串替代CSRF Token作为频道名订阅，问题依旧存在
• 预发布环境中，浏览器每10秒向wss://myapp-staging.com/cable发送Keepalive GET请求，返回101状态码，Rails日志显示Successfully upgraded to WebSocket，本地环境无此现象

求助疑问 #

请问我遗漏了哪些配置或排查步骤？可能的错误点有哪些？

内容的提问来源于stack exchange，提问作者squeezeitthroughthekeyhole