File Download Upload

Upload

You can easily handle file uploads in Beego, just don’t forget to add this attribute enctype="multipart/form-data" to your form, otherwise your browser won’t transfer your uploaded file.

If the file size is larger than the set cache memory size, then it will be placed in a temporary file, the default cache memory is 64M, you can adjust this cache memory size by following:

web.MaxMemory = 1<<22

Or in configuration files:

maxmemory = 1<<22

At the same time, Beego provides another parameter, MaxUploadSize, to limit the maximum upload file size - if you upload multiple files at once, then it limits the size of all those files combined together.

By default, MaxMemory should be set smaller than MaxUploadSize, and the effect of combining the two parameters in this case is:

1. if the file size is smaller than MaxMemory, it will be processed directly in memory.
2. if the file size is between MaxMemory and MaxUploadSize, the portion larger than MaxMemory will be placed in a temporary directory.
3. the file size exceeds MaxUploadSize, the request is rejected directly and the response code is returned 413

Beego provides two very convenient ways to handle file uploads:

• GetFile(key string) (multipart.File, *multipart.FileHeader, error)

• SaveToFile(fromfile, tofile string) error

<form enctype="multipart/form-data" method="post">
  <input type="file" name="uploadname" />
  <input type="submit" />
</form>

Saving file example:

func (c *FormController) Post() {
    f, h, err := c.GetFile("uploadname")
    if err != nil {
        log.Fatal("getfile err ", err)
    }
    defer f.Close()
    c.SaveToFile("uploadname", "static/upload/" + h.Filename) 
}

Download

func (output *BeegoOutput) Download(file string, filename ...string) {}

Example:

func (ctrl *MainController) DownloadFile() {
    // The file LICENSE is under root path.
    // and the downloaded file name is license.txt
    ctrl.Ctx.Output.Download("LICENSE", "license.txt")
}

In particular, note that the first parameter of the Download method is the file path, that is, the file to be downloaded; the second parameter is an indefinite parameter, representing the file name when the user saves it locally.

If the first parameter uses a relative path, then it represents a relative path calculated from the current working directory.

Reference

• Static files