Go: http file upload
<p>I am trying to upload a file as an attachment from a client written in Go.
I am using http multipart CreateFormFile. When I do this, it sends the data in body to the server which server rejects.</p>

<pre><code>file, err := os.Open(*img.Filepath)
if err != nil {
    return err
}

defer file.Close()

body := &amp;bytes.Buffer{}
writer := multipart.NewWriter(body)
part, err := writer.CreateFormFile("asset", filepath.Base(*img.Filepath))
if err != nil {
    return err
}
_, err = io.Copy(part, file)
if err != nil {
    return err
}

contentType := writer.FormDataContentType()
err = writer.Close()
if err != nil {
    return err
}

request, err := http.NewRequest("POST", API_URL, body)
if err != nil {
    return err
}

request.Header.Set("Content-Type", contentType)

values := request.URL.Query()
values.Add("filename", util.GetFileNameWithoutExtension(*img.FileName))
request.URL.RawQuery = values.Encode()
client := &amp;http.Client{}
resp, err := client.Do(request)
if err != nil {
    return err
} else {
    respBody := &amp;bytes.Buffer{}
    _, err = respBody.ReadFrom(resp.Body)
    if err != nil {
        return err
    }
    resp.Body.Close()
}
</code></pre>

<p>When I try the same using curl it works
curl -X POST -F "<strong>asset=@filepath</strong>" "<a href="http://localhost/api/v1/xyz?filename=filename" rel="nofollow">http://localhost/api/v1/xyz?filename=filename</a>"</p>

<p>How can I implement key=@val functionality with Go?</p>