Golang 文件上传时如何防止文件损坏？

package main

import (
    "crypto/md5"
    "fmt"
    "io"
    "io/ioutil"
    "net/http"
    "os"
)

func main() {
    // 监听端口 8080
    http.HandleFunc("/", handleUpload)
    http.ListenAndServe(":8080", nil)
}

func handleUpload(w http.ResponseWriter, r *http.Request) {
    // 获取上传的文件
    file, _, err := r.FormFile("file")
    if err != nil {
        http.Error(w, "Error retrieving file", http.StatusBadRequest)
        return
    }

    // 计算原始文件的 MD5 哈希值
    originalHash := md5.New()
    io.Copy(originalHash, file)
    originalHashString := fmt.Sprintf("%x", originalHash.Sum(nil))

    // 创建临时文件保存上传的文件
    tmpFile, err := ioutil.TempFile("", "file-upload")
    if err != nil {
        http.Error(w, "Error creating temporary file", http.StatusInternalServerError)
        return
    }
    defer os.Remove(tmpFile.Name())

    // 将文件内容保存到临时文件中
    if _, err := io.Copy(tmpFile, file); err != nil {
        http.Error(w, "Error saving file", http.StatusInternalServerError)
        return
    }

    // 计算接收文件的 MD5 哈希值
    receivedHash := md5.New()
    receivedFile, err := os.Open(tmpFile.Name())
    if err != nil {
        http.Error(w, "Error opening temporary file", http.StatusInternalServerError)
        return
    }
    io.Copy(receivedHash, receivedFile)
    receivedHashString := fmt.Sprintf("%x", receivedHash.Sum(nil))

    // 比较哈希值
    if originalHashString != receivedHashString {
        http.Error(w, "File was corrupted during upload", http.StatusBadRequest)
        return
    }

    // 成功上传文件
    w.Write([]byte("File uploaded successfully"))
}