当Nginx代理websockt,其中涉及到了一个Nginx的设计问题 End-to-end and Hop-by-hop Headers
需要添加map配置,map在Nginx中是为一个或多个变量设置映射表

http {
    map $http_upgrade $connection_upgrade {
    default upgrade;
    ''      close;
}
server {

location / {
…
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
    }
}
}