const (// BEncoding represents Base64 encoding scheme as defined byRFC 2045.BEncoding =WordEncoder('b')// QEncoding represents the Q-encoding scheme as defined byRFC 2047.QEncoding =WordEncoder('q'))

var ErrInvalidMediaParameter =errors.New("mime: invalid media parameter")

funcAddExtensionType¶

func AddExtensionType(ext, typstring)error

AddExtensionType sets the MIME type associated withthe extension ext to typ. The extension should begin witha leading dot, as in ".html".

funcExtensionsByType¶added ingo1.5

func ExtensionsByType(typstring) ([]string,error)

ExtensionsByType returns the extensions known to be associated with the MIMEtype typ. The returned extensions will each begin with a leading dot, as in".html". When typ has no associated extensions, ExtensionsByType returns annil slice.

funcFormatMediaType¶

func FormatMediaType(tstring, param map[string]string)string

FormatMediaType serializes mediatype t and the parametersparam as a media type conforming toRFC 2045 andRFC 2616.The type and parameter names are written in lower-case.When any of the arguments result in a standard violation thenFormatMediaType returns the empty string.

package mainimport ("fmt""mime")func main() {mediatype := "text/html"params := map[string]string{"charset": "utf-8",}result := mime.FormatMediaType(mediatype, params)fmt.Println("result:", result)}

Output:result: text/html; charset=utf-8

funcParseMediaType¶

func ParseMediaType(vstring) (mediatypestring, params map[string]string, errerror)

ParseMediaType parses a media type value and any optionalparameters, perRFC 1521. Media types are the values inContent-Type and Content-Disposition headers (RFC 2183).On success, ParseMediaType returns the media type convertedto lowercase and trimmed of white space and a non-nil map.If there is an error parsing the optional parameter,the media type will be returned along with the errorErrInvalidMediaParameter.The returned map, params, maps from the lowercaseattribute to the attribute value with its case preserved.

package mainimport ("fmt""mime")func main() {mediatype, params, err := mime.ParseMediaType("text/html; charset=utf-8")if err != nil {panic(err)}fmt.Println("type:", mediatype)fmt.Println("charset:", params["charset"])}

Output:type: text/htmlcharset: utf-8

funcTypeByExtension¶

func TypeByExtension(extstring)string

TypeByExtension returns the MIME type associated with the file extension ext.The extension ext should begin with a leading dot, as in ".html".When ext has no associated type, TypeByExtension returns "".

Extensions are looked up first case-sensitively, then case-insensitively.

The built-in table is small but on unix it is augmented by the localsystem's MIME-info database or mime.types file(s) if available under one ormore of these names:

/usr/local/share/mime/globs2/usr/share/mime/globs2/etc/mime.types/etc/apache2/mime.types/etc/apache/mime.types

On Windows, MIME types are extracted from the registry.

Text types have the charset parameter set to "utf-8" by default.

typeWordDecoder¶added ingo1.5

type WordDecoder struct {// CharsetReader, if non-nil, defines a function to generate// charset-conversion readers, converting from the provided// charset into UTF-8.// Charsets are always lower-case. utf-8, iso-8859-1 and us-ascii charsets// are handled by default.// One of the CharsetReader's result values must be non-nil.CharsetReader func(charsetstring, inputio.Reader) (io.Reader,error)}

A WordDecoder decodes MIME headers containingRFC 2047 encoded-words.

func (d *WordDecoder) Decode(wordstring) (string,error)

package mainimport ("bytes""fmt""io""mime")func main() {dec := new(mime.WordDecoder)header, err := dec.Decode("=?utf-8?q?=C2=A1Hola,_se=C3=B1or!?=")if err != nil {panic(err)}fmt.Println(header)dec.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {switch charset {case "x-case":// Fake character set for example.// Real use would integrate with packages such// as code.google.com/p/go-charsetcontent, err := io.ReadAll(input)if err != nil {return nil, err}return bytes.NewReader(bytes.ToUpper(content)), nildefault:return nil, fmt.Errorf("unhandled charset %q", charset)}}header, err = dec.Decode("=?x-case?q?hello!?=")if err != nil {panic(err)}fmt.Println(header)}

Output:¡Hola, señor!HELLO!

func (d *WordDecoder) DecodeHeader(headerstring) (string,error)

package mainimport ("bytes""fmt""io""mime")func main() {dec := new(mime.WordDecoder)header, err := dec.DecodeHeader("=?utf-8?q?=C3=89ric?= <eric@example.org>, =?utf-8?q?Ana=C3=AFs?= <anais@example.org>")if err != nil {panic(err)}fmt.Println(header)header, err = dec.DecodeHeader("=?utf-8?q?=C2=A1Hola,?= =?utf-8?q?_se=C3=B1or!?=")if err != nil {panic(err)}fmt.Println(header)dec.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {switch charset {case "x-case":// Fake character set for example.// Real use would integrate with packages such// as code.google.com/p/go-charsetcontent, err := io.ReadAll(input)if err != nil {return nil, err}return bytes.NewReader(bytes.ToUpper(content)), nildefault:return nil, fmt.Errorf("unhandled charset %q", charset)}}header, err = dec.DecodeHeader("=?x-case?q?hello_?= =?x-case?q?world!?=")if err != nil {panic(err)}fmt.Println(header)}

Output:Éric <eric@example.org>, Anaïs <anais@example.org>¡Hola, señor!HELLO WORLD!

typeWordEncoder¶added ingo1.5

type WordEncoderbyte

A WordEncoder is anRFC 2047 encoded-word encoder.

func (eWordEncoder) Encode(charset, sstring)string

package mainimport ("fmt""mime")func main() {fmt.Println(mime.QEncoding.Encode("utf-8", "¡Hola, señor!"))fmt.Println(mime.QEncoding.Encode("utf-8", "Hello!"))fmt.Println(mime.BEncoding.Encode("UTF-8", "¡Hola, señor!"))fmt.Println(mime.QEncoding.Encode("ISO-8859-1", "Caf\xE9"))}

Output:=?utf-8?q?=C2=A1Hola,_se=C3=B1or!?=Hello!=?UTF-8?b?wqFIb2xhLCBzZcOxb3Ih?==?ISO-8859-1?q?Caf=E9?=