RFC 2045

Content-Type

Content -Typeはtype/subtypeとそれに続く任意の個数のパラメータで構成される。

パラメータはattribute=value

type/subtypeとパラメータの間、またはパラメータ同士の間はセミコロン

code:Syntax of the Content-Type Header Field

content := "Content-Type" ":" type "/" subtype

*(";" parameter)

; Matching of media type and subtype

; is ALWAYS case-insensitive.

type := discrete-type / composite-type

discrete-type := "text" / "image" / "audio" / "video" /

"application" / extension-token

composite-type := "message" / "multipart" / extension-token

extension-token := ietf-token / x-token

ietf-token := <An extension token defined by a

standards-track RFC and registered

with IANA.>

x-token := <The two characters "X-" or "x-" followed, with

no intervening white space, by any token>

subtype := extension-token / iana-token

iana-token := <A publicly-defined extension token. Tokens

of this form must be registered with IANA

as specified in RFC 2048.>

parameter := attribute "=" value

attribute := token

; Matching of attributes

; is ALWAYS case-insensitive.

value := token / quoted-string

token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,

or tspecials>

tspecials := "(" / ")" / "<" / ">" / "@" /

"," / ";" / ":" / "\" / <">

; Must be in quoted-string,

; to use within parameter values