后台：修复直播开播页空白（补全 watch 导入）；控制台展示应用带宽观测与 HTTP 流量统计

Made-with: Cursor

server/middleware/traffic_meter.go

@@ -0,0 +1,53 @@
+package middleware
+
+import (
+	"io"
+	"net/http"
+
+	"yh_web/server/pkg/traffic"
+
+	"github.com/gin-gonic/gin"
+)
+
+type countReadCloser struct {
+	io.ReadCloser
+}
+
+func (c *countReadCloser) Read(p []byte) (int, error) {
+	n, err := c.ReadCloser.Read(p)
+	if n > 0 {
+		traffic.AddIn(n)
+	}
+	return n, err
+}
+
+type meterResponseWriter struct {
+	gin.ResponseWriter
+}
+
+func (w *meterResponseWriter) Write(p []byte) (int, error) {
+	n, err := w.ResponseWriter.Write(p)
+	if n > 0 {
+		traffic.AddOut(n)
+	}
+	return n, err
+}
+
+func (w *meterResponseWriter) WriteString(s string) (int, error) {
+	n, err := w.ResponseWriter.WriteString(s)
+	if n > 0 {
+		traffic.AddOut(n)
+	}
+	return n, err
+}
+
+// TrafficMeter 统计 HTTP 请求体与响应体字节量（进程级，非网卡级）。
+func TrafficMeter() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if c.Request.Body != nil && c.Request.Body != http.NoBody {
+			c.Request.Body = &countReadCloser{ReadCloser: c.Request.Body}
+		}
+		c.Writer = &meterResponseWriter{ResponseWriter: c.Writer}
+		c.Next()
+	}
+}