Add tcp socket example

Author: devlights

examples/socket/README.md

@@ -2,3 +2,5 @@
 
 - [TCP:基本パターン](./tcp_basic/)
   - 一番基本的なパターン
+- [TCP:io.Copyを使う](./tcp_use_iocopy/)
+  - io.Copyを使っているパターン

examples/socket/tcp_use_iocopy/.gitignore

@@ -0,0 +1,3 @@
+client/client
+server/server
+.task/

examples/socket/tcp_use_iocopy/Taskfile.yml

@@ -0,0 +1,42 @@
+version: '3'
+
+tasks:
+  default:
+    cmds:
+      - task: run
+  run:
+    cmds:
+      - task: build-server
+      - task: build-client
+      - task: start-server
+      - task: run-client
+  build-server:
+    dir: server
+    cmds:
+      - go build
+    sources:
+      - ./*.go
+    generates:
+      - server{{exeExt}}
+    method: checksum
+  build-client:
+    dir: client
+    cmds:
+      - go build
+    sources:
+      - ./*.go
+    generates:
+      - client{{exeExt}}
+    method: checksum
+  start-server:
+    dir: server
+    cmds:
+      - ./server &
+  run-client:
+    dir: client
+    cmds:
+      - ./client
+  clean:
+    cmds:
+      - (cd client; go clean)
+      - (cd server; go clean)

examples/socket/tcp_use_iocopy/client/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"bytes"
+	_ "embed"
+	"io"
+	"log"
+	"net"
+	"os"
+)
+
+var (
+	appLog = log.New(os.Stdout, "[client] ", 0)
+	//go:embed main.go
+	data []byte
+)
+
+func main() {
+	//
+	// Connect
+	//
+	laddr, _ := net.ResolveTCPAddr("tcp", "localhost:")
+	raddr, _ := net.ResolveTCPAddr("tcp", "localhost:8888")
+
+	conn, _ := net.DialTCP("tcp", laddr, raddr)
+	defer func() {
+		appLog.Println("close connection...")
+		conn.Close()
+	}()
+
+	//
+	// Send
+	//
+	conn.Write(data)
+	appLog.Printf("%dbyte(s) send", len(data))
+
+	conn.CloseWrite()
+	appLog.Println("close client-side write stream")
+
+	//
+	// Recv
+	//
+	buf := new(bytes.Buffer)
+	io.Copy(buf, conn)
+	appLog.Printf("%dbyte(s) recv", len(buf.Bytes()))
+}

examples/socket/tcp_use_iocopy/server/main.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"bytes"
+	_ "embed"
+	"io"
+	"log"
+	"net"
+	"os"
+
+	"github.com/devlights/gomy/errs"
+)
+
+var (
+	appLog = log.New(os.Stdout, "[server] ", 0)
+	//go:embed main.go
+	data []byte
+)
+
+func main() {
+	//
+	// Start
+	//
+	server, _ := net.ListenTCP("tcp", errs.Drop(net.ResolveTCPAddr("tcp", "localhost:8888")))
+	defer func() {
+		server.Close()
+		appLog.Println("shutting down...")
+	}()
+
+	//
+	// Accept
+	//
+	conn, _ := server.AcceptTCP()
+	defer func() {
+		appLog.Println("close connection...")
+		conn.Close()
+	}()
+
+	//
+	// Recv
+	//
+	buf := new(bytes.Buffer)
+	io.Copy(buf, conn)
+	appLog.Printf("%dbyte(s) recv", len(buf.Bytes()))
+
+	//
+	// Send
+	//
+	conn.Write(data)
+	appLog.Printf("%dbyte(s) send", len(data))
+	conn.CloseWrite()
+	appLog.Println("close server-side write stream")
+}