Golang文件上传下载进度控制方法

func uploadFileWithProgress(filePath, url string) error {
    file, err := os.Open(filePath)
    if err != nil {
        return err
    }
    defer file.Close()
fileInfo, _ := file.Stat()
totalSize := fileInfo.Size()

// 创建带进度的读取器
progressReader := &progressReader{file: file, totalSize: totalSize}

// 创建 multipart 请求体
var body bytes.Buffer
writer := multipart.NewWriter(&body)
part, _ := writer.CreateFormFile("upload", filepath.Base(filePath))

io.Copy(part, progressReader)
writer.Close()

// 发送请求
req, _ := http.NewRequest("POST", url, &body)
req.Header.Set("Content-Type", writer.FormDataContentType)

client := &http.Client{}
resp, err := client.Do(req)
if resp != nil {
    defer resp.Body.Close()
}

return err
}
// 带进度的读取器
type progressReader struct {
file      *os.File
totalSize int64
bytesRead int64
}
func (pr *progressReader) Read(p []byte) (n int, err error) {
n, err = pr.file.Read(p)
atomic.AddInt64(&pr.bytesRead, int64(n))
// 打印进度（可替换为回调或 channel）
fmt.Printf("上传进度: %.2f%%\n", float64(pr.bytesRead)/float64(pr.totalSize)*100)
return n, err
}

func downloadFileWithProgress(url, savePath string) error {
    resp, err := http.Get(url)
    if err != nil {
        return err
    }
    defer resp.Body.Close()
file, err := os.Create(savePath)
if err != nil {
    return err
}
defer file.Close()

totalSize := resp.ContentLength
bytesRead := int64(0)

reader := &progressReaderDL{
    Reader:      resp.Body,
    totalSize:   totalSize,
    bytesRead:   &bytesRead,
}

_, err = io.Copy(file, reader)
return err
}
type progressReaderDL struct {
io.Reader
totalSize int64
bytesRead *int64
}
func (pr *progressReaderDL) Read(p []byte) (n int, err error) {
n, err = pr.Reader.Read(p)
atomic.AddInt64(pr.bytesRead, int64(n))
if pr.totalSize > 0 {
    percent := float64(*pr.bytesRead) / float64(pr.totalSize) * 100
    fmt.Printf("下载进度: %.2f%%\n", percent)
}
return n, err
}

type ProgressCallback func(bytesRead, totalBytes int64)