From 50791c9ca06a5f21a5ddbe212e27538399816762 Mon Sep 17 00:00:00 2001
From: Ken2mer <kitadate2@gmail.com>
Date: Sun, 28 Feb 2021 18:16:25 +0900
Subject: [PATCH] net.Listen, net.Accept

HTTPServer inspired by https://ascii.jp/elem/000/001/276/1276572/
---
 net/listen.go      | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 net/listen_test.go | 41 ++++++++++++++++++++++++++++
 2 files changed, 107 insertions(+)
 create mode 100644 net/listen.go
 create mode 100644 net/listen_test.go

diff --git a/net/listen.go b/net/listen.go
new file mode 100644
index 0000000..201de86
--- /dev/null
+++ b/net/listen.go
@@ -0,0 +1,66 @@
+package net
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"os"
+	"os/signal"
+	"strings"
+)
+
+// HTTPServer inspired by https://ascii.jp/elem/000/001/276/1276572/
+func HTTPServer(port string) error {
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt)
+
+	ln, err := net.Listen("tcp", "localhost:"+port)
+	if err != nil {
+		return err
+	}
+
+	go func() {
+		s := <-c
+		fmt.Println("Got signal:", s)
+		ln.Close()
+	}()
+
+	fmt.Println("Server is running at localhost:" + port)
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			return err
+		}
+		go func() {
+			fmt.Printf("Accept %v\n", conn.RemoteAddr())
+
+			// リクエストを読み込む
+			request, err := http.ReadRequest(bufio.NewReader(conn))
+			if err != nil {
+				fmt.Println(err)
+				return
+			}
+			dump, err := httputil.DumpRequest(request, true)
+			if err != nil {
+				fmt.Println(err)
+				return
+			}
+			fmt.Println(string(dump))
+
+			// レスポンスを書き込む
+			response := http.Response{
+				StatusCode: 200,
+				ProtoMajor: 1,
+				ProtoMinor: 0,
+				Body:       io.NopCloser(strings.NewReader("Hello World\n")),
+			}
+			response.Write(conn)
+
+			conn.Close()
+		}()
+	}
+}
diff --git a/net/listen_test.go b/net/listen_test.go
new file mode 100644
index 0000000..33fdb48
--- /dev/null
+++ b/net/listen_test.go
@@ -0,0 +1,41 @@
+package net
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func TestHTTPServer(t *testing.T) {
+	port := "8080"
+	errCh := make(chan error)
+	go func() {
+		errCh <- HTTPServer(port)
+	}()
+	time.Sleep(time.Second * 1)
+
+	resp, err := http.Get("http://localhost:" + port)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	status := resp.StatusCode
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if status != 200 {
+		t.Fatalf("expected: 200, got: %d", resp.StatusCode)
+	}
+	if string(body) != "Hello World\n" {
+		t.Fatalf("expected: Hello World\n, got: %s", body)
+	}
+
+	syscall.Kill(syscall.Getpid(), syscall.SIGINT)
+	fmt.Println(<-errCh)
+}