Nginx 如何配置 WebSocket 代理？

WebSocket 是一种在单个 TCP 连接上进行全双工通信的协议。Nginx 可以作为 WebSocket 代理，将客户端的 WebSocket 连接转发到后端服务器。

基本配置：

nginx
map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

server {
    listen 80;
    server_name example.com;

    location /ws {
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        
        # 超时设置
        proxy_connect_timeout 7d;
        proxy_send_timeout 7d;
        proxy_read_timeout 7d;
    }
}

关键配置说明：

proxy_http_version 1.1：WebSocket 需要 HTTP/1.1 协议
Upgrade 和 Connection 头：告诉 Nginx 这是一个 WebSocket 连接
超时设置：WebSocket 是长连接，需要设置较长的超时时间

完整配置示例：

nginx
http {
    upstream websocket_backend {
        server 192.168.1.100:8080;
        server 192.168.1.101:8080;
    }

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

    server {
        listen 80;
        server_name example.com;

        # WebSocket 代理
        location /ws {
            proxy_pass http://websocket_backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;

            # 超时设置（根据实际需求调整）
            proxy_connect_timeout 60s;
            proxy_send_timeout 3600s;
            proxy_read_timeout 3600s;

            # 禁用缓冲
            proxy_buffering off;
        }

        # 普通请求
        location / {
            proxy_pass http://backend;
            proxy_set_header Host $host;
        }
    }
}

HTTPS WebSocket 配置：

nginx
server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /etc/nginx/ssl/example.com.crt;
    ssl_certificate_key /etc/nginx/ssl/example.com.key;

    location /ws {
        proxy_pass http://websocket_backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_set_header Host $host;
        
        proxy_connect_timeout 7d;
        proxy_send_timeout 7d;
        proxy_read_timeout 7d;
    }
}

WebSocket 负载均衡：

nginx
upstream websocket_backend {
    # 使用 ip_hash 保持会话
    ip_hash;
    server 192.168.1.100:8080;
    server 192.168.1.101:8080;
    server 192.168.1.102:8080;
}

注意事项：

会话保持：WebSocket 连接需要保持到同一台后端服务器，使用 ip_hash 或 sticky 模块
超时设置：根据业务需求设置合适的超时时间
缓冲：WebSocket 实时通信需要禁用缓冲
防火墙：确保防火墙允许长连接
负载均衡：避免使用轮询策略，会导致连接中断

性能优化：

nginx
# 增加 worker 连接数
events {
    worker_connections 4096;
}

# 调整 keepalive
upstream websocket_backend {
    server 192.168.1.100:8080;
    keepalive 32;
}

# 优化 TCP 参数
location /ws {
    proxy_pass http://websocket_backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    
    # TCP 优化
    proxy_socket_keepalive on;
    proxy_connect_timeout 60s;
    proxy_send_timeout 3600s;
    proxy_read_timeout 3600s;
}

多路径 WebSocket：

nginx
# 不同路径转发到不同后端
location /chat/ws {
    proxy_pass http://chat_backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
}

location /notification/ws {
    proxy_pass http://notification_backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
}

监控和日志：

nginx
# 自定义日志格式
log_format websocket '$remote_addr - $remote_user [$time_local] '
                     '"$request" $status $body_bytes_sent '
                     '"$http_referer" "$http_user_agent" '
                     'rt=$request_time uct="$upstream_connect_time" '
                     'uht="$upstream_header_time" urt="$upstream_response_time"';

access_log /var/log/nginx/websocket_access.log websocket;

# 监控连接数
location /nginx_status {
    stub_status on;
    access_log off;
}

故障排查：

连接断开：检查超时设置是否合理
无法连接：检查 Upgrade 和 Connection 头是否正确
负载均衡问题：使用 ip_hash 保持会话
性能问题：调整 worker_connections 和缓冲设置