Golang文件上传下载并发处理实战

func uploadHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method != "POST" {
        http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
        return
    }
<pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">// 限制上传大小为10MB
r.ParseMultipartForm(10 << 20)

file, handler, err := r.FormFile("file")
if err != nil {
    http.Error(w, "获取文件失败", http.StatusBadRequest)
    return
}
defer file.Close()

// 检查文件类型（简单示例）
buffer := make([]byte, 512)
_, _ = file.Read(buffer)
fileType := http.DetectContentType(buffer)
if !strings.HasPrefix(fileType, "image/") {
    http.Error(w, "仅支持图片文件", http.StatusBadRequest)
    return
}
// 重置文件指针
file.Seek(0, 0)

// 生成唯一文件名
filename := fmt.Sprintf("%d_%s", time.Now().Unix(), handler.Filename)
dst, err := os.Create("./uploads/" + filename)
if err != nil {
    http.Error(w, "创建文件失败", http.StatusInternalServerError)
    return
}
defer dst.Close()

// 写入文件
io.Copy(dst, file)
w.Write([]byte("上传成功: " + filename))

func downloadHandler(w http.ResponseWriter, r *http.Request) {
    filename := r.URL.Query().Get("file")
    filepath := "./uploads/" + filename
<pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">file, err := os.Open(filepath)
if err != nil {
    http.Error(w, "文件不存在", http.StatusNotFound)
    return
}
defer file.Close()

w.Header().Set("Content-Disposition", "attachment; filename="+filename)
w.Header().Set("Content-Type", "application/octet-stream")

// 使用固定缓冲区流式传输
buf := make([]byte, 32*1024)
io.CopyBuffer(w, file, buf)

server := &http.Server{
    Addr:    ":8080",
    Handler: router,
    ReadTimeout:  10 * time.Second,
    WriteTimeout: 30 * time.Second,
}