add ch13

ch13/3/ch13_3.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net"
+	"net/http"
+	"time"
+)
+
+type RFCTime struct {
+	DayOfWeek  string `json:"day_of_week"`
+	DayOfMonth int    `json:"day_of_month"`
+	Month      string `json:"month"`
+	Year       int    `json:"year"`
+	Hour       int    `json:"hour"`
+	Minute     int    `json:"minute"`
+	Second     int    `json:"second"`
+}
+
+type TimeHandler struct{}
+
+func StructToJsString(data any) string {
+	var b bytes.Buffer
+	enc := json.NewEncoder(&b)
+	err := enc.Encode(data)
+	if err != nil {
+		slog.Error("Problems with encoding json")
+	}
+	return b.String()
+}
+
+func (th TimeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	headerAccept := http.Header.Get(r.Header, "Accept")
+	var output string
+	switch headerAccept {
+	case "application/json":
+		currTime := time.Now()
+		rfcTime := RFCTime{
+			DayOfWeek:  currTime.Weekday().String(),
+			DayOfMonth: currTime.Day(),
+			Month:      currTime.Month().String(),
+			Year:       currTime.Year(),
+			Hour:       currTime.Hour(),
+			Minute:     currTime.Minute(),
+			Second:     currTime.Second(),
+		}
+		output = StructToJsString(rfcTime)
+	default:
+		output = time.Now().Format(time.RFC3339)
+	}
+	w.Write([]byte(output))
+}
+
+func RequestToIP(r *http.Request) string {
+	ip, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		slog.Error(fmt.Sprintf("Wrong format of address: %q", r.RemoteAddr))
+	}
+	return ip
+}
+
+func RequestIPHandler(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		slog.Info(RequestToIP(r))
+		h.ServeHTTP(w, r)
+	})
+}
+
+func main() {
+	server := http.Server{
+		Addr:         ":10100",
+		ReadTimeout:  30 * time.Second,
+		WriteTimeout: 90 * time.Second,
+		IdleTimeout:  120 * time.Second,
+		Handler:      RequestIPHandler(TimeHandler{}),
+	}
+	err := server.ListenAndServe()
+	if err != nil {
+		if err != http.ErrServerClosed {
+			panic(err)
+		}
+	}
+}

ch13/3/go.mod

@@ -0,0 +1,3 @@
+module gitea.local.lab/Lbenedar/learning_go/ch13/3
+
+go 1.25.0