Go文件上传下载

愚辛 · · 4200 次点击 · · 开始浏览

这是一个创建于的文章，其中的信息可能已经有所发展或是发生改变。

Go自带很多包，本例使用io包和net包相应的API简单实现基于http的文件上传下载(仅为demo)

定义文件存储文件

//假设文件上传为本地的服务器，上传的基础路径
const BaseUploadPath = "/var/file"

main函数中监听http服务

func main() {
    http.HandleFunc("/upload", handleUpload)
    http.HandleFunc("/download", handleDownload)

    err := http.ListenAndServe(":3000", nil)
    if err != nil  {
        log.Fatal("Server run fail")
    }
}

文件上传处理器

func handleUpload (w http.ResponseWriter, request *http.Request)  {
    //文件上传只允许POST方法
    if request.Method != http.MethodPost {
        w.WriteHeader(http.StatusMethodNotAllowed)
        _, _ = w.Write([]byte("Method not allowed"))
        return
    }

    //从表单中读取文件
    file, fileHeader, err := request.FormFile("file")
    if err != nil {
        _, _ = io.WriteString(w, "Read file error")
        return
    }
    //defer 结束时关闭文件
    defer file.Close()
    log.Println("filename: " + fileHeader.Filename)

    //创建文件
    newFile, err := os.Create(BaseUploadPath + "/" + fileHeader.Filename)
    if err != nil {
        _, _ = io.WriteString(w, "Create file error")
        return
    }
    //defer 结束时关闭文件
    defer newFile.Close()

    //将文件写到本地
    _, err = io.Copy(newFile, file)
    if err != nil {
        _, _ = io.WriteString(w, "Write file error")
        return
    }
    _,_ = io.WriteString(w, "Upload success")
}

文件下载处理器

func handleDownload (w http.ResponseWriter, request *http.Request) {
    //文件上传只允许GET方法
    if request.Method != http.MethodGet {
        w.WriteHeader(http.StatusMethodNotAllowed)
        _, _ = w.Write([]byte("Method not allowed"))
        return
    }
    //文件名
    filename := request.FormValue("filename")
    if filename == "" {
        w.WriteHeader(http.StatusBadRequest)
        _, _ = io.WriteString(w, "Bad request")
        return
    }
    log.Println("filename: " + filename)
    //打开文件
    file, err := os.Open(BaseUploadPath + "/" + filename)
    if err != nil {
        w.WriteHeader(http.StatusBadRequest)
        _, _ = io.WriteString(w, "Bad request")
        return
    }
    //结束后关闭文件
    defer file.Close()

    //设置响应的header头
    w.Header().Add("Content-type", "application/octet-stream")
    w.Header().Add("content-disposition", "attachment; filename=\""+filename+"\"")
    //将文件写至responseBody
    _, err = io.Copy(w, file)
    if err != nil {
        w.WriteHeader(http.StatusBadRequest)
        _, _ = io.WriteString(w, "Bad request")
        return
    }
}