TypeByExtension
fmt.Println(mime.TypeByExtension(".pdf")) // application/pdf
fmt.Println(mime.TypeByExtension(".go")) // text/plain; charset=utf-8mime
MIME types: look up by extension, parse Content-Type parameters, and encode/decode RFC 2047 encoded-words.
Type lookup
ExtensionsByType
exts, _ := mime.ExtensionsByType("image/jpeg")
fmt.Println(exts) // [.jfif .jpe .jpeg .jpg]AddExtensionType — register a custom mapping
mime.AddExtensionType(".myapp", "application/vnd.myapp+json")Parsing Content-Type
ParseMediaType
mt, params, _ := mime.ParseMediaType("multipart/form-data; boundary=xyz")
fmt.Println(mt, params["boundary"])FormatMediaType — build one back
s := mime.FormatMediaType("text/plain", map[string]string{"charset": "utf-8"})
// "text/plain; charset=utf-8"