Handle Http Upload Zip file in Golang

Question

I'm using golang net/http package to retrieve the uploaded zip file via postman. The attachment file link. It is not dangerous file. Feel free to check out.

Development env

• local machine m1 macbook pro golang 1.17.2 - no issue
• server docker image golang:1.17.5-stretch - got issue.

Code to capture the post form transSourceFile file.

func HandleFileReqTest(w http.ResponseWriter, req *http.Request, params map[string]string) err {

    if err := req.ParseMultipartForm(32 << 20); err != nil {
       return err
    }

    file, header, err := req.FormFile("transSourceFile")
    if err != nil {
       return err
    }
    defer file.Close()
    fmt.Println("header.Size:", header.Size)
    return nil
}

I tried below code also no use

func HandleFileReqTest(w http.ResponseWriter, req *http.Request, params map[string]string) err {
    if err := req.ParseForm(); err != nil {
        return err
    }
    req.ParseMultipartForm(32 << 20)
    file, header, err := req.FormFile("transSourceFile")
    if err != nil {
        return err
    }
    defer file.Close()
    fmt.Println("header.Size:", header.Size)
    return nil
}

Result: Local machine got the same file size as the origin file. Server with golang:1.17.5-stretch got the different file size compare to origin file.

As the result on this, i'm unable to unzip the file in the server. Anyone can help?

Answer 1

You need to copy form file to the actual file:

f, err := os.Create("some.zip")
defer f.Close()
n, err := io.Copy(f, file)

Answer 2

Data isn't being flushed to the file completely. You should close the file first to ensure that the data is fully flushed.

  // create a local file filename
    dst, err := os.Create("filename.zip")

      // save it
     fl, err = io.Copy(dst, src)

     // Close the file
     dst.Close()

     stat, _ := dst.Stat()

 //Now check the size stat.Size() or header.Size after flushing the file.