Bug 反馈：nginx 反向代理至 SiYuan 服务端时存在内核连接中断的异常

经测试，该异常仅在 nginx 反向代理环境发生，直接将服务暴露出去不会出现问题，异常界面如下图所示：

Docker 运行 b3log/siyuan 时，前台错误信息输出如下：

2021/09/21 19:37:52 [Recovery] 2021/09/21 - 19:37:52 panic recovered:
runtime error: invalid memory address or nil pointer dereference
/usr/local/go/src/runtime/panic.go:221 (0x4535a6)
/usr/local/go/src/runtime/signal_unix.go:735 (0x453576)
/go/pkg/mod/github.com/gorilla/websocket@v1.4.2/conn.go:1184 (0xc20746)
/go/pkg/mod/github.com/88250/melody@v0.0.0-20201115062536-c0b3394adcd1/melody.go:172 (0xc2072e)
/go/pkg/mod/github.com/88250/melody@v0.0.0-20201115062536-c0b3394adcd1/melody.go:161 (0xed7717)
/go/src/github.com/siyuan-note/siyuan-src/kernel/server/serve.go:194 (0xed76dd)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0xc149ec)
/go/pkg/mod/github.com/gin-contrib/sessions@v0.0.3/sessions.go:52 (0xc149d8)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0xeaceac)
/go/pkg/mod/github.com/gin-contrib/gzip@v0.0.3/handler.go:60 (0xeace82)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0xc0bca1)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/recovery.go:99 (0xc0bc8c)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/context.go:165 (0xc0ab5d)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/gin.go:489 (0xc0a7e5)
/go/pkg/mod/github.com/gin-gonic/gin@v1.7.4/gin.go:445 (0xc0a344)
/usr/local/go/src/net/http/server.go:2878 (0x7582da)
/usr/local/go/src/net/http/server.go:1929 (0x753987)
/usr/local/go/src/runtime/asm_amd64.s:1581 (0x4708e0)

Docker 运行命令如下：

docker run --restart=on-failure:3 -p 127.0.0.1:6806:6806 -v /data/SiYuanNote/:/data b3log/siyuan -accessAuthCode xxx  -workspace /data -servePath note.xxx.cn -ssl

Nginx 配置如下：

server {
        listen 443;
        ssl on;
        ssl_certificate /etc/letsencrypt/live/xxx.cn/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/xxx.cn/privkey.pem;
        server_name note.xxx.cn;
        location / {
                proxy_pass http://127.0.0.1:6806/;
        }
}

server {
        listen 80;
        server_name note.xxx.cn;
        rewrite .* https://$host$1 permanent;
}

其他运行环境：

• KVM 虚拟化云主机
• Docker version 20.10.8, build 3967b7d
• OS: Debian 10 buster
• Kernel: x86_64 Linux 4.19.0-16-amd64