Function writeMultipartFormFile

middleware.go:62–124

(w *multipart.Writer, file *FileUpload, r *Request)

}

func writeMultipartFormFile(w *multipart.Writer, file *FileUpload, r *Request) error {
	content, err := file.GetFileContent()
	if err != nil {
		return err
	}
	defer content.Close()
	if r.RetryAttempt > 0 { // reset file reader when retry a multipart file upload
		if rs, ok := content.(io.ReadSeeker); ok {
			_, err = rs.Seek(0, io.SeekStart)
			if err != nil {
				return err
			}
		}
	}
	// Auto detect actual multipart content type
	cbuf := make([]byte, 512)
	seeEOF := false
	lastTime := time.Now()
	size, err := content.Read(cbuf)
	if err != nil {
		if err == io.EOF {
			seeEOF = true
		} else {
			return err
		}
	}

	ct := file.ContentType
	if ct == "" {
		ct = http.DetectContentType(cbuf)
	}
	pw, err := w.CreatePart(createMultipartHeader(file, ct))
	if err != nil {
		return err
	}

	if r.forceChunkedEncoding && r.uploadCallback != nil {
		pw = &callbackWriter{
			Writer:    pw,
			lastTime:  lastTime,
			interval:  r.uploadCallbackInterval,
			totalSize: file.FileSize,
			callback: func(written int64) {
				r.uploadCallback(UploadInfo{
					ParamName:    file.ParamName,
					FileName:     file.FileName,
					FileSize:     file.FileSize,
					UploadedSize: written,
				})
			},
		}
	}

	if _, err = pw.Write(cbuf[:size]); err != nil {
		return err
	}
	if seeEOF {
		return nil