add ch14

ch14/3/ch14_3.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"time"
+)
+
+type TimeHandler struct{}
+
+func (th TimeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Write([]byte(time.Now().Format(time.RFC3339)))
+}
+
+type Level string
+
+const (
+	Debug Level = "debug"
+	Info  Level = "info"
+)
+
+func ExtractLogLevel(ctx context.Context) Level {
+	return ctx.Value("log_level").(Level)
+}
+
+func StoreLogLevel(ctx context.Context, level Level) context.Context {
+	return context.WithValue(ctx, "log_level", level)
+}
+
+func GetLogLevelQuery(http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		logLevel := r.URL.Query().Get("log_level")
+		if logLevel != "info" && logLevel != "debug" {
+			slog.Info("Wrong logLevel")
+		}
+		Log(StoreLogLevel(r.Context(), Level(logLevel)), Debug, "Test message")
+	})
+}
+
+func Log(ctx context.Context, level Level, message string) {
+	var inLevel Level
+	inLevel = ExtractLogLevel(ctx)
+	if level == Debug && inLevel == Debug {
+		fmt.Println(message)
+	}
+	if level == Info && (inLevel == Debug || inLevel == Info) {
+		fmt.Println(message)
+	}
+}
+
+func main() {
+	server := http.Server{
+		Addr:         ":10100",
+		ReadTimeout:  30 * time.Second,
+		WriteTimeout: 90 * time.Second,
+		IdleTimeout:  120 * time.Second,
+		Handler:      GetLogLevelQuery(TimeHandler{}),
+	}
+	err := server.ListenAndServe()
+	if err != nil {
+		if err != http.ErrServerClosed {
+			panic(err)
+		}
+	}
+}