From 1f4ba997b7243767b80f24342749a3536bdf4719 Mon Sep 17 00:00:00 2001
From: lbenedar <lbenedar@local.lab>
Date: Mon, 23 Feb 2026 15:00:41 +0300
Subject: [PATCH] add ch13

---
 ch13/1/ch13_1.go | 28 ++++++++++++++++
 ch13/1/go.mod    |  3 ++
 ch13/2/ch13_2.go | 46 ++++++++++++++++++++++++++
 ch13/2/go.mod    |  3 ++
 ch13/3/ch13_3.go | 86 ++++++++++++++++++++++++++++++++++++++++++++++++
 ch13/3/go.mod    |  3 ++
 6 files changed, 169 insertions(+)
 create mode 100644 ch13/1/ch13_1.go
 create mode 100644 ch13/1/go.mod
 create mode 100644 ch13/2/ch13_2.go
 create mode 100644 ch13/2/go.mod
 create mode 100644 ch13/3/ch13_3.go
 create mode 100644 ch13/3/go.mod

diff --git a/ch13/1/ch13_1.go b/ch13/1/ch13_1.go
new file mode 100644
index 0000000..1840a34
--- /dev/null
+++ b/ch13/1/ch13_1.go
@@ -0,0 +1,28 @@
+package main
+
+import (
+	"net/http"
+	"time"
+)
+
+type TimeHandler struct{}
+
+func (th TimeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Write([]byte(time.Now().Format(time.RFC3339)))
+}
+
+func main() {
+	server := http.Server{
+		Addr:         ":10100",
+		ReadTimeout:  30 * time.Second,
+		WriteTimeout: 90 * time.Second,
+		IdleTimeout:  120 * time.Second,
+		Handler:      TimeHandler{},
+	}
+	err := server.ListenAndServe()
+	if err != nil {
+		if err != http.ErrServerClosed {
+			panic(err)
+		}
+	}
+}
diff --git a/ch13/1/go.mod b/ch13/1/go.mod
new file mode 100644
index 0000000..0a5f101
--- /dev/null
+++ b/ch13/1/go.mod
@@ -0,0 +1,3 @@
+module gitea.local.lab/Lbenedar/learning_go/ch13/1
+
+go 1.25.0
diff --git a/ch13/2/ch13_2.go b/ch13/2/ch13_2.go
new file mode 100644
index 0000000..a877d51
--- /dev/null
+++ b/ch13/2/ch13_2.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"net"
+	"net/http"
+	"time"
+)
+
+type TimeHandler struct{}
+
+func (th TimeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Write([]byte(time.Now().Format(time.RFC3339)))
+}
+
+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)
+		}
+	}
+}
diff --git a/ch13/2/go.mod b/ch13/2/go.mod
new file mode 100644
index 0000000..6271f23
--- /dev/null
+++ b/ch13/2/go.mod
@@ -0,0 +1,3 @@
+module gitea.local.lab/Lbenedar/learning_go/ch13/2
+
+go 1.25.0
diff --git a/ch13/3/ch13_3.go b/ch13/3/ch13_3.go
new file mode 100644
index 0000000..691acfa
--- /dev/null
+++ b/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)
+		}
+	}
+}
diff --git a/ch13/3/go.mod b/ch13/3/go.mod
new file mode 100644
index 0000000..989d243
--- /dev/null
+++ b/ch13/3/go.mod
@@ -0,0 +1,3 @@
+module gitea.local.lab/Lbenedar/learning_go/ch13/3
+
+go 1.25.0