如何用 Golang 实现文件上传进度显示_Golang HTTP Client 文件传输示例

package main

import (
    "fmt"
    "io"
    "mime/multipart"
    "net/http"
    "os"
    "sync"
)

// ProgressReader 记录已读字节数并触发回调
type ProgressReader struct {
    file     io.Reader
    total    int64
    read     int64
    callback func(read, total int64)
    mu       sync.Mutex
}

func (pr *ProgressReader) Read(p []byte) (n int, err error) {
    n, err = pr.file.Read(p)
    pr.mu.Lock()
    pr.read += int64(n)
    pr.callback(pr.read, pr.total)
    pr.mu.Unlock()
    return n, err
}

// NewProgressReader 创建带进度回调的 Reader
func NewProgressReader(file io.Reader, total int64, callback func(read, total int64)) *ProgressReader {
    return &ProgressReader{
        file:     file,
        total:    total,
        read:     0,
        callback: callback,
    }
}

func uploadFile(filepath, url string) error {
    file, err := os.Open(filepath)
    if err != nil {
        return err
    }
    defer file.Close()

    fileInfo, _ := file.Stat()
    totalSize := fileInfo.Size()

    body := &bytes.Buffer{}
    writer := multipart.NewWriter(body)

    // 添加文件字段
    part, err := writer.CreateFormFile("upload", filepath)
    if err != nil {
        return err
    }

    // 包装原始文件为带进度的 Reader
    progressReader := NewProgressReader(file, totalSize, func(read, total int64) {
        fmt.Printf("\r上传进度: %d / %d (%.2f%%)", read, total, float64(read)/float64(total)*100)
    })

    _, err = io.Copy(part, progressReader)
    if err != nil {
        return err
    }

    err = writer.Close()
    if err != nil {
        return err
    }

    // 发起请求
    req, err := http.NewRequest("POST", url, body)
    if err != nil {
        return err
    }
    req.Header.Set("Content-Type", writer.FormDataContentType())

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

    fmt.Printf("\n上传完成，服务器返回状态: %s\n", resp.Status)
    return nil
}

func main() {
    err := uploadFile("./test.pdf", "https://httpbin.org/post")
    if err != nil {
        fmt.Printf("上传失败: %v\n", err)
    }
}

上传进度: 102400 / 512000 (20.00%)