添加聊天工具项目的基本结构和功能实现，包括用户认证、消息处理、文件传输及数据库操作

chat_project/README.md

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+# 简易聊天工具项目
+
+## 项目结构
+
+```
+chat_project/
+├── server/
+│   ├── main.go              # 服务器入口
+│   ├── auth.go              # 用户认证模块
+│   ├── message.go           # 消息处理模块
+│   ├── file_transfer.go     # 文件传输模块
+│   ├── db.go                # 数据库操作模块
+├── client/
+│   ├── main.go              # 客户端入口
+│   ├── auth.go              # 客户端认证模块
+│   ├── message.go           # 客户端消息处理
+│   ├── file_transfer.go     # 客户端文件传输
+├── go.mod
+└── go.sum
+```
+
+## 技术选型
+
+- Go 1.24
+- TCP协议自定义消息格式
+- SQLite数据库用于聊天记录持久化
+- bcrypt加密用于密码存储
+- 命令行客户端实现
+
+## 开发步骤
+
+1. 搭建TCP服务器和客户端基础连接框架
+2. 实现用户身份认证
+3. 实现聊天消息传输
+4. 集成聊天记录持久化
+5. 实现文件和图片传输
+6. 完善客户端命令行交互
+7. 测试与优化
+8. 编写文档与交付

chat_project/auth.go

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+package main
+
+import (
+	"errors"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// 用户结构体
+type User struct {
+	Username     string
+	PasswordHash []byte
+}
+
+// 模拟用户存储（实际应存入数据库）
+var users = map[string]User{}
+
+// 注册用户
+func RegisterUser(username, password string) error {
+	if _, exists := users[username]; exists {
+		return errors.New("用户已存在")
+	}
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+	users[username] = User{
+		Username:     username,
+		PasswordHash: hash,
+	}
+	return nil
+}
+
+// 用户登录验证
+func AuthenticateUser(username, password string) error {
+	user, exists := users[username]
+	if !exists {
+		return errors.New("用户不存在")
+	}
+	err := bcrypt.CompareHashAndPassword(user.PasswordHash, []byte(password))
+	if err != nil {
+		return errors.New("密码错误")
+	}
+	return nil
+}

chat_project/client/file_transfer.go

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+package main
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+)
+
+// 客户端接收文件的示例函数
+func ReceiveFile(conn net.Conn, filename string, filesize int64) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	var received int64 = 0
+	buf := make([]byte, 4096)
+	for received < filesize {
+		n, err := conn.Read(buf)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		file.Write(buf[:n])
+		received += int64(n)
+	}
+	fmt.Printf("文件 %s 接收完成，共 %d 字节\n", filename, received)
+	return nil
+}
+
+// 客户端发送文件的示例函数
+func SendFile(conn net.Conn, filepath string) error {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	buf := make([]byte, 4096)
+	for {
+		n, err := file.Read(buf)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		_, err = conn.Write(buf[:n])
+		if err != nil {
+			return err
+		}
+	}
+	fmt.Printf("文件 %s 发送完成\n", filepath)
+	return nil
+}

chat_project/client/main.go

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+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"net"
+	"os"
+)
+
+func main() {
+	conn, err := net.Dial("tcp", "127.0.0.1:8888")
+	if err != nil {
+		log.Fatalf("无法连接服务器: %v", err)
+	}
+	defer conn.Close()
+	fmt.Println("已连接到服务器 127.0.0.1:8888")
+
+	// 启动协程接收服务器消息
+	go func() {
+		buf := make([]byte, 1024)
+		for {
+			n, err := conn.Read(buf)
+			if err != nil {
+				log.Printf("读取服务器消息错误: %v", err)
+				os.Exit(0)
+			}
+			fmt.Printf("服务器消息: %s\n", string(buf[:n]))
+		}
+	}()
+
+	// 从命令行读取输入并发送给服务器
+	scanner := bufio.NewScanner(os.Stdin)
+	for {
+		fmt.Print("请输入消息: ")
+		if !scanner.Scan() {
+			break
+		}
+		text := scanner.Text()
+		if text == "exit" {
+			fmt.Println("退出客户端")
+			break
+		}
+		_, err := conn.Write([]byte(text))
+		if err != nil {
+			log.Printf("发送消息失败: %v", err)
+			break
+		}
+	}
+}

chat_project/go.mod

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+module chatv1
+
+go 1.24.0
+
+require (
+	github.com/mattn/go-sqlite3 v1.14.28 // indirect
+	golang.org/x/crypto v0.38.0 // indirect
+)

chat_project/go.sum

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+github.com/mattn/go-sqlite3 v1.14.28 h1:ThEiQrnbtumT+QMknw63Befp/ce/nUPgBPMlRFEum7A=
+github.com/mattn/go-sqlite3 v1.14.28/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
+golang.org/x/crypto v0.38.0 h1:jt+WWG8IZlBnVbomuhg2Mdq0+BBQaHbtqHEFEigjUV8=
+golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=

chat_project/server/db.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"database/sql"
+	"log"
+	"time"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+var db *sql.DB
+
+func InitDB() {
+	var err error
+	db, err = sql.Open("sqlite3", "./chat.db")
+	if err != nil {
+		log.Fatalf("打开数据库失败: %v", err)
+	}
+
+	createTableSQL := `
+    CREATE TABLE IF NOT EXISTS messages (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        sender TEXT NOT NULL,
+        receiver TEXT NOT NULL,
+        content TEXT NOT NULL,
+        timestamp DATETIME NOT NULL
+    );
+    `
+	_, err = db.Exec(createTableSQL)
+	if err != nil {
+		log.Fatalf("创建表失败: %v", err)
+	}
+}
+
+func SaveMessage(sender, receiver, content string) error {
+	stmt, err := db.Prepare("INSERT INTO messages(sender, receiver, content, timestamp) VALUES (?, ?, ?, ?)")
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+
+	_, err = stmt.Exec(sender, receiver, content, time.Now())
+	return err
+}
+
+func GetMessages(sender, receiver string) ([]Message, error) {
+	rows, err := db.Query("SELECT sender, receiver, content, timestamp FROM messages WHERE (sender = ? AND receiver = ?) OR (sender = ? AND receiver = ?) ORDER BY timestamp ASC", sender, receiver, receiver, sender)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var messages []Message
+	for rows.Next() {
+		var msg Message
+		var ts string
+		err = rows.Scan(&msg.Sender, &msg.Receiver, &msg.Content, &ts)
+		if err != nil {
+			return nil, err
+		}
+		msg.Timestamp, _ = time.Parse(time.RFC3339, ts)
+		messages = append(messages, msg)
+	}
+	return messages, nil
+}
+
+type Message struct {
+	Sender    string
+	Receiver  string
+	Content   string
+	Timestamp time.Time
+}

chat_project/server/file_transfer.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+)
+
+// 服务器端接收文件的示例函数
+func ReceiveFile(conn net.Conn, filename string, filesize int64) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	var received int64 = 0
+	buf := make([]byte, 4096)
+	for received < filesize {
+		n, err := conn.Read(buf)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		file.Write(buf[:n])
+		received += int64(n)
+	}
+	fmt.Printf("文件 %s 接收完成，共 %d 字节\n", filename, received)
+	return nil
+}
+
+// 服务器端发送文件的示例函数
+func SendFile(conn net.Conn, filepath string) error {
+	file, err := os.Open(filepath)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	buf := make([]byte, 4096)
+	for {
+		n, err := file.Read(buf)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		_, err = conn.Write(buf[:n])
+		if err != nil {
+			return err
+		}
+	}
+	fmt.Printf("文件 %s 发送完成\n", filepath)
+	return nil
+}

chat_project/server/main.go

@@ -0,0 +1,75 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"net"
+	"sync"
+)
+
+var (
+	clients   = make(map[net.Conn]string) // 连接映射：连接对象到用户名
+	clientsMu sync.Mutex                  // 保护clients的互斥锁
+)
+
+func main() {
+	listener, err := net.Listen("tcp", ":8888")
+	if err != nil {
+		log.Fatalf("监听端口失败: %v", err)
+	}
+	defer listener.Close()
+	fmt.Println("服务器已启动，监听端口 8888")
+
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Printf("接受连接失败: %v", err)
+			continue
+		}
+		go handleConnection(conn)
+	}
+}
+
+func handleConnection(conn net.Conn) {
+	defer func() {
+		// 连接关闭时，移除客户端
+		clientsMu.Lock()
+		delete(clients, conn)
+		clientsMu.Unlock()
+		conn.Close()
+		broadcast(fmt.Sprintf("用户退出：%s", conn.RemoteAddr().String()), "系统")
+		fmt.Printf("客户端断开：%s\n", conn.RemoteAddr().String())
+	}()
+
+	// 添加新连接
+	clientsMu.Lock()
+	clients[conn] = conn.RemoteAddr().String()
+	clientsMu.Unlock()
+
+	// 通知所有客户端有新用户加入
+	broadcast(fmt.Sprintf("新用户加入：%s", conn.RemoteAddr().String()), "系统")
+
+	scanner := bufio.NewScanner(conn)
+	for scanner.Scan() {
+		msg := scanner.Text()
+		sender := clients[conn]
+		broadcast(msg, sender)
+	}
+	if err := scanner.Err(); err != nil {
+		log.Printf("读取消息错误: %v", err)
+	}
+}
+
+func broadcast(message, sender string) {
+	clientsMu.Lock()
+	defer clientsMu.Unlock()
+	for c := range clients {
+		if c != nil {
+			_, err := fmt.Fprintf(c, "[%s] %s\n", sender, message)
+			if err != nil {
+				log.Printf("广播失败: %v", err)
+			}
+		}
+	}
+}