package main import ( "mime" "path/filepath" "strings" "time" "fmt" ) type Info struct { Keywords []string // tags Ip string // who uploaded it Random int64 TimeStamp time.Time "timestamp,omitempty" } type File struct { Metadata Info ",omitempty" Md5 string ChunkSize int UploadDate time.Time Length int64 Filename string ",omitempty" IsImage bool ContentType string "contentType,omitempty" } func (f *File) SetIsImage() { m_type := mime.TypeByExtension(filepath.Ext(f.Filename)) f.IsImage = strings.Contains(m_type, "image") fmt.Println(f.Filename,f.IsImage) }