使用TCP和KCP传输一张图片

基于Go分别在两台虚拟机上使用TCP和KCP传输一张图片的demo

TCP传输

TCP服务端

使用服务端接收图片,此虚拟机的ip是192.168.10.107

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package main

import (
"bytes"
"fmt"
"io"
"net"
"os"
"time"
)

func main() {
lis, err := net.Listen("tcp", "192.168.10.107:10000")
if err != nil {
fmt.Printf("Error connecting to server: %s\n", err)
return
}
defer lis.Close()

// 创建本地文件用于保存接收的图片数据
file, err := os.Create("received_image.png")
if err != nil {
fmt.Printf("Error creating file: %s\n", err)
return
}
defer file.Close()

// 创建一个缓冲区,用于接收数据
buffer := make([]byte, 1024*256)
endSignal := []byte("TRANSFER_COMPLETED")

startTime := time.Now()

conn, err := lis.Accept()
if err != nil {
panic(err)
}
defer conn.Close()

fmt.Println(time.Now())

for {
n, err := conn.Read(buffer)
if err != nil {
if err == io.EOF {
break // 读取结束
}
fmt.Printf("Error reading data: %s\n", err)
return
}

// 检查是否收到结束标志
if bytes.Equal(buffer[:n], endSignal) {
break
}

// 将数据写入本地文件
_, err = file.Write(buffer[:n])
if err != nil {
fmt.Printf("Error writing to file: %s\n", err)
return
}

}

endTime := time.Now()
elapsedTime := endTime.Sub(startTime)
print(elapsedTime.Milliseconds())

// 获取文件大小
fileInfo, err := file.Stat()
if err != nil {
fmt.Printf("Error getting file info: %s\n", err)
return
}
fileSize := fileInfo.Size()
fmt.Println(fileSize)

// 计算传输速度
transferSpeed := float64(fileSize) / float64((elapsedTime.Milliseconds() * (1024 * 1024))/1000) // MB/s

fmt.Printf("File transfer complete. Transfer speed: %.2f MB/s\n", transferSpeed)

}
收起代码

首先监听本地ip和相应端口,获取一个listener,通过listener的Accept方法后就可以获取一个连接,通过连接便可传送数据。先创建一个空文件和缓冲区,进入循环,循环中将连接的数据写入到缓冲区中,获取得到的字节数n,并将数据写入到本地文件,直到遇到传输结束信号”TRANSFER_COMPLETED”

TCP客户端

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package main

import (
"fmt"
"io"
"log"
"net"
"os"
"time"
)


func main() {
// kcp
// conn, err := kcp.DialWithOptions(serverAddr, nil, 10, 3)
// tcp
conn, err := net.Dial("tcp", "192.168.10.107:10000")
if err!= nil {
fmt.Println(err)
}
defer conn.Close()
if err != nil {
log.Fatal("Listen failed:", err)
}

fmt.Println("Server started, waiting for connections...")

handleClientWithTCP(conn)
}

func handleClientWithTCP(conn net.Conn) {

file, err := os.Open("mountain.png")
if err != nil {
log.Fatal("Create file failed:", err)
}
defer file.Close()

buf := make([]byte, 1024*256)

for {
n, err := file.Read(buf)
if err != nil {
if err != io.EOF {
log.Println("Read from file failed:", err)
}
break
}

_, err = conn.Write(buf[:n])
if err != nil {
log.Println("Write to client failed:", err)
break
}
}

// 图片传输完成后发送结束标志
_, err = conn.Write([]byte("TRANSFER_COMPLETED"))
if err != nil {
fmt.Printf("Error sending completion signal: %s\n", err)
return
}

fmt.Println(time.Now())
fmt.Println("Image transfer completed.")
}
收起代码

获取到连接conn后,循环将文件数据file写入到缓冲区中,然后将缓冲区的数据发送到连接中,直到遇到io.EOF跳出循环,发送了结束标志

KCP传输

KCP服务端

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package main

import (
"bytes"
"fmt"
"github.com/xtaci/kcp-go"
"io"
"net"
"os"
"time"
)

const (
serverAddr = "192.168.10.107:10000"

)

func kcpRecv() {
// 这里的10, 3是设置了前向纠错
// 也可以使用kcp.Listen,与tcp接口兼容 但是默认没有使用前向纠错
lis, err := kcp.ListenWithOptions(serverAddr, nil, 10, 3)
if err != nil {
fmt.Printf("Error connecting to server: %s\n", err)
return
}
defer lis.Close()

// 创建本地文件用于保存接收的图片数据
file, err := os.Create("received_image.png")
if err != nil {
fmt.Printf("Error creating file: %s\n", err)
return
}
defer file.Close()

// 创建一个缓冲区,用于接收数据
buffer := make([]byte, 1024*256)
endSignal := []byte("TRANSFER_COMPLETED")

startTime := time.Now()

conn, err := lis.AcceptKCP()
if err != nil {
panic(err)
}
defer conn.Close()

fmt.Println(time.Now())

for {
n, err := conn.Read(buffer)
if err != nil {
if err == io.EOF {
break // 读取结束
}
fmt.Printf("Error reading data: %s\n", err)
return
}

// 检查是否收到结束标志
if bytes.Equal(buffer[:n], endSignal) {
break
}

// 将数据写入本地文件
_, err = file.Write(buffer[:n])
if err != nil {
fmt.Printf("Error writing to file: %s\n", err)
return
}

}

endTime := time.Now()
elapsedTime := endTime.Sub(startTime)

// 获取文件大小
fileInfo, err := file.Stat()
if err != nil {
fmt.Printf("Error getting file info: %s\n", err)
return
}
fileSize := fileInfo.Size()

// 计算传输速度
transferSpeed := float64(fileSize) / elapsedTime.Seconds() / (1024 * 1024) // MB/s

fmt.Printf("File transfer complete. Transfer speed: %.2f MB/s\n", transferSpeed)

}
收起代码

kcp-go与tcp的接口做了兼容处理,可以无障碍替换使用tcp,也增加了一些可选项,如前向纠错,如kcp.ListenWithOptions(serverAddr, nil, 10, 3)的10和3就代表着每发送10个包就发送3个冗余包

KCP客户端

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package main

import (
"time"
"fmt"
"log"
"os"
"io"
"github.com/xtaci/kcp-go"
)

const (
serverAddr = "192.168.10.107:10000"
)

func kcpSend() {
conn, err := kcp.DialWithOptions(serverAddr, nil, 10, 3)
if err!= nil {
fmt.Println(err)
}
defer conn.Close()
if err != nil {
log.Fatal("Listen failed:", err)
}

fmt.Println("Server started, waiting for connections...")

handleClient(conn)
}

func handleClient(conn *kcp.UDPSession) {

file, err := os.Open("mountain.png")
if err != nil {
log.Fatal("Create file failed:", err)
}
defer file.Close()

buf := make([]byte, 1024*256)

for {
n, err := file.Read(buf)
if err != nil {
if err != io.EOF {
log.Println("Read from file failed:", err)
}
break
}

_, err = conn.Write(buf[:n])
if err != nil {
log.Println("Write to client failed:", err)
break
}
}

// 图片传输完成后发送结束标志
_, err = conn.Write([]byte("TRANSFER_COMPLETED"))
if err != nil {
fmt.Printf("Error sending completion signal: %s\n", err)
return
}

fmt.Println(time.Now())
fmt.Println("Image transfer completed.")
}
收起代码