How to implement file transfer function in Golang

This article mainly introduces the file transfer function of Golang in detail. The sample code in the article is very detailed and has certain For reference value, interested friends can refer to

The example in this article shares the specific code for file transfer in Golang for your reference. The specific content As follows

Use TCP to complete file transmission. The basic idea is as follows:

1. The sender (client) sends the file name to the server, and the server saves the file name.

2. The receiver (server) returns an ok message to the client to confirm that the file name is saved successfully.

3. After receiving the message, the sender (client) starts sending file data to the server.

4. The receiver (server) reads the file content and writes it to the previously saved file.

#Get the file name first. Use the stat() function in the os package to obtain file attribute information. Include the file name and file size in the file properties returned by the function. The Stat parameter name is passed in the absolute path of file access. The Name() function in FileInfo can extract the file name separately.

func Stat(name string) (FileInfo, error) 
type FileInfo interface {
   Name() string       
   Size() int64        
   Mode() FileMode     
   ModTime() time.Time 
   IsDir() bool        
   Sys() interface{}   
}

Sender:

package main
 
import (
    "fmt"
    "io"
    "net"
    "os"
)
 
func sendFile(conn net.Conn, filePath string) {
    // 只读打开文件
    f, err := os.Open(filePath)
    if err != nil {
        fmt.Println("os.Open err:", err)
        return
    }
    defer f.Close()
 
    // 从本文件中，读数据，写给网络接收端。 读多少，写多少。原封不动。
    buf := make([]byte, 1024)
    for {
        n, err := f.Read(buf)
        if err != nil {
            if err == io.EOF {
                fmt.Println("发送文件完成。")
            } else {
                fmt.Println("os.Open err:", err)
            }
            return
        }
        // 写到网络socket中
        _, err = conn.Write(buf[:n])
        if err != nil {
            fmt.Println("conn.Write err:", err)
            return
        }
    }
}
 
func main() {
    list := os.Args // 获取命令行参数
 
    if len(list) != 2 {
        fmt.Println("格式为：go run xxx.go 文件绝对路径")
        return
    }
    // 提取 文件的绝对路径
    filePath := list[1]
 
    //提取文件名
    fileInfo, err := os.Stat(filePath)
    if err != nil {
        fmt.Println("os.Stat err:", err)
        return
    }
    fileName := fileInfo.Name()
 
    // 主动发起连接请求
    conn, err := net.Dial("tcp", "127.0.0.1:8000")
    if err != nil {
        fmt.Println("net.Dial err:", err)
        return
    }
    defer conn.Close()
 
    // 发送文件名给 接收端
    _, err = conn.Write([]byte(fileName))
    if err != nil {
        fmt.Println("conn.Write err:", err)
        return
    }
    // 读取服务器回发的 OK
    buf := make([]byte, 1024)
    n, err := conn.Read(buf)
    if err != nil {
        fmt.Println("conn.Read err:", err)
        return
    }
 
    if "ok" == string(buf[:n]) {
        // 写文件内容给服务器——借助conn
        sendFile(conn, filePath)
    }
}

Receiver:

package main
 
import (
    "fmt"
    "net"
    "os"
)
 
func recvFile(conn net.Conn, fileName string) {
    // 按照文件名创建新文件
    f, err := os.Create(fileName)
    if err != nil {
        fmt.Println("os.Create err:", err)
        return
    }
    defer f.Close()
 
    // 从 网络中读数据，写入本地文件
    buf := make([]byte, 1024)
    for {
        n, _ := conn.Read(buf)
        if n == 0 {
            fmt.Println("接收文件完成。")
            return
        }
        // 写入本地文件，读多少，写多少。
        f.Write(buf[:n])
    }
}
 
func main() {
    // 创建用于监听的socket
    listener, err := net.Listen("tcp", "127.0.0.1:8000")
    if err != nil {
        fmt.Println(" net.Listen err:", err)
        return
    }
    defer listener.Close()
 
    fmt.Println("接收端启动成功，等待发送端发送文件！")
 
    // 阻塞监听
    conn, err := listener.Accept()
    if err != nil {
        fmt.Println(" listener.Accept() err:", err)
        return
    }
    defer conn.Close()
 
    // 获取文件名，保存
    buf := make([]byte, 1024)
    n, err := conn.Read(buf)
    if err != nil {
        fmt.Println(" conn.Read err:", err)
        return
    }
    fileName := string(buf[:n])
 
    // 回写 ok 给发送端
    conn.Write([]byte("ok"))
 
    // 获取文件内容
    recvFile(conn, fileName)
}

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