How to Receive multipart from the client in golang?

Question

Here my code and output:

func RestClient(req *http.Request) {
        fmt.Println("main (120):::", req.MultipartForm.File)
}

main (120)::: &{map[userName:[0xc4200a66e0] diamond:[0xc4200f67b0] ]}

for k,v := range req.MultipartForm.File{
              if k == "userName" {
                for _, v2 := range v {
                    fmt.Println("main (130):::",v2)
                } 
              }     
           }

 > main (130)::: &{ map[Content-Length:[8]
    > Content-Disposition:[form-data; name="dk"]
    > Content-Transfer-Encoding:[binary] Content-Type:[multipart/form-data;
    > charset=utf-8]] 8 [117 115 101 114 78 97 109 101] }

I want the (slice byte [117 115 101 114 78 97 109 101]) but can’t pull out that, how can print the (content []byte), As we know the field from FileHeader struct:

type FileHeader struct {
    Filename string
    Header   textproto.MIMEHeader
    Size     int64

    content []byte
    tmpfile string
}

Thanks in advance.

Answer 1

Call FileHeader.Open, which returns a multipart.File:

type File interface {
        io.Reader
        io.ReaderAt
        io.Seeker
        io.Closer
}

How you deal with this file depends on what you want to do with the contents. ioutil.ReadAll is an option, but often it is more convenient to leave it as-is and use io.Copy to write the content to another io.Writer. Don't forget to call Close after you're done reading.