什么是 MIME TYPE? 一、首先,我们要了解浏览器是如何处理内容的。在浏览器中显示的内容有 HTML、有 XML、有 GIF、还有 Flash ……那么,浏览器是如何区分它们,决定什么内容用什么形式来显示呢?答案是 MIME Type,也就是该资源的媒体类型。
媒体类型通常是通过 HTTP 协议,由 Web 服务器告知浏览器的,更准确地说,是通过 Content-Type 来表示的,例如:
Content-Type: text/HTML
表示内容是 text/HTML 类型,也就是超文本文件。为什么是“text/HTML”而不是“HTML/text”或者别的什么?MIME Type 不是个人指定的,是经过 ietf 组织协商,以 RFC 的形式作为建议的标准发布在网上的,大多数的 Web 服务器和用户代理都会支持这个规范 (顺便说一句,Email 附件的类型也是通过 MIME Type 指定的)。
通常只有一些在互联网上获得广泛应用的格式才会获得一个 MIME Type,如果是某个客户端自己定义的格式,一般只能以 application/x- 开头。
XHTML 正是一个获得广泛应用的格式,因此,在 RFC 3236 中,说明了 XHTML 格式文件的 MIME Type 应该是 application/xHTML+XML。
当然,处理本地的文件,在没有人告诉浏览器某个文件的 MIME Type 的情况下,浏览器也会做一些默认的处理,这可能和你在操作系统中给文件配置的 MIME Type 有关。比如在 Windows 下,打开注册表的“HKEY_LOCAL_MACHINESOFTWAREClassesMIMEDatabaseContent Type”主键,你可以看到所有 MIME Type 的配置信息。
二、在把输出结果传送到浏览器上的时候,浏览器必须启动适当的应用程序来处理这个输出文档。这可以通过多种类型MIME(多功能网际邮件扩充协议)来完成。在HTTP中,MIME类型被定义在Content-Type header中。
例如,架设你要传送一个Microsoft Excel文件到客户端。那么这时的MIME类型就是“application/vnd.ms-excel”。在大多数实际情况中,这个文件然后将传送给Execl来处理(假设我们设定Execl为处理特殊MIME类型的应用程序)。在ASP中,设定MIME类型的方法是通过Response对象的ContentType属性。
多媒体文件格式MIME
最早的HTTP协议中,并没有附加的数据类型信息,所有传送的数据都被客户程序解释为超文本标记语言HTML 文档,而为了支持多媒体数据类型,HTTP协议中就使用了附加在文档之前的MIME数据类型信息来标识数据类型。
MIME意为多目Internet邮件扩展,它设计的最初目的是为了在发送电子邮件时附加多媒体数据,让邮件客户程序能根据其类型进行处理。然而当它被HTTP协议支持之后,它的意义就更为显著了。它使得HTTP传输的不仅是普通的文本,而变得丰富多彩。
每个MIME类型由两部分组成,前面是数据的大类别,例如声音audio、图象image等,后面定义具体的种类。
常见的MIME类型
超文本标记语言文本 .html,.html text/html
普通文本 .txt text/plain
RTF文本 .rtf application/rtf
GIF图形 .gif image/gif
JPEG图形 .ipeg,.jpg image/jpeg
au声音文件 .au audio/basic
MIDI音乐文件 mid,.midi audio/midi,audio/x-midi
RealAudio音乐文件 .ra, .ram audio/x-pn-realaudio
MPEG文件 .mpg,.mpeg video/mpeg
AVI文件 .avi video/x-msvideo
GZIP文件 .gz application/x-gzip
TAR文件 .tar application/x-tar
Internet中有一个专门组织IANA来确认标准的MIME类型,但Internet发展的太快,很多应用程序等不及IANA来确认他们使用的MIME类型为标准类型。因此他们使用在类别中以x-开头的方法标识这个类别还没有成为标准,例如:x-gzip,x-tar等。事实上这些类型运用的很广泛,已经成为了事实标准。只要客户机和服务器共同承认这个MIME类型,即使它是不标准的类型也没有关系,客户程序就能根据MIME类型,采用具体的处理手段来处理数据。而Web服务器和浏览器(包括操作系统)中,缺省都设置了标准的和常见的MIME类型,只有对于不常见的 MIME类型,才需要同时设置服务器和客户浏览器,以进行识别。
由于MIME类型与文档的后缀相关,因此服务器使用文档的后缀来区分不同文件的MIME类型,服务器中必须定义文档后缀和MIME类型之间的对应关系。而客户程序从服务器上接收数据的时候,它只是从服务器接受数据流,并不了解文档的名字,因此服务器必须使用附加信息来告诉客户程序数据的MIME类型。服务器在发送真正的数据之前,就要先发送标志数据的MIME类型的信息,这个信息使用Content-type关键字进行定义,例如对于HTML文档,服务器将首先发送以下两行MIME标识信息,这个标识并不是真正的数据文件的一部分。
Content-type: text/html
注意,第二行为一个空行,这是必须的,使用这个空行的目的是将MIME信息与真正的数据内容分隔开。
MIME (Multipurpose Internet Mail Extensions) 是描述消息内容类型的因特网标准。
MIME 消息能包含文本、图像、音频、视频以及其他应用程序专用的数据。
官方的 MIME 信息是由 Internet Engineering Task Force (IETF) 在下面的文档中提供的:
RFC-822 Standard for ARPA Internet text messages
RFC-2045 MIME Part 1: Format of Internet Message Bodies
RFC-2046 MIME Part 2: Media Types
RFC-2047 MIME Part 3: Header Extensions for Non-ASCII Text
RFC-2048 MIME Part 4: Registration Procedures
RFC-2049 MIME Part 5: Conformance Criteria and Examples
不同的应用程序支持不同的 MIME 类型。
MIME Types
MIME 类型 MIME (Multipurpose Internet Mail Extensions) is an Internet standard for describes message content types.
MIME ( 多用途的网际邮件扩充协议)是用于描述信息内容类型的国际标准。
MIME messages can contain text, images, audio, video, and other application-specific data.
MIME 信息可以包含文本、图像、音频、视频和其他的应用程序细节数据。
Official MIME info is provided by the Internet Engineering Task Force (IETF) in the following documents:
官方的MIME信息是由internet工程任务组(IETF)中的下列文档所提供的:
RFC-822 Standard for ARPA Internet text messages [ARPA互连网文本信息标准]
RFC-2045 MIME Part 1: Format of Internet Message Bodies [MIME 第1部分:互联网信息主体的格式]
RFC-2046 MIME Part 2: Media Types [MIME 第2部分:多媒体类型]
RFC-2047 MIME Part 3: Header Extensions for Non-ASCII Text [MIME 第3部分:非ASCII文本的页眉扩展名]
RFC-2048 MIME Part 4: Registration Procedures [MIME 第4部分:注册程序]
RFC-2049 MIME Part 5: Conformance Criteria and Examples [MIME 第5部分:一致性标准和案例]
Different applications support different MIME types.
不同的应用程序支持不同的MIME类型。
The reference below is a list of MIME types supported by Microsoft Internet Information Server version 5.
微软IIS5以上版本支持下面关于MIME类型的参数列表。
MIME Types By Content Type
Content [内容] 类型 中的 MIME 类型
Type/sub-type 类型/二级类型 |
Extension 扩展名 |
application/envoy
evy
application/fractals
fif
application/futuresplash
spl
application/hta
hta
application/internet-property-stream
acx
application/mac-binhex40
hqx
application/msword
doc
application/msword
dot
application/octet-stream
*
application/octet-stream
bin
application/octet-stream
class
application/octet-stream
dms
application/octet-stream
exe
application/octet-stream
lha
application/octet-stream
lzh
application/oda
oda
application/olescript
axs
application/pdf
pdf
application/pics-rules
prf
application/pkcs10
p10
application/pkix-crl
crl
application/postscript
ai
application/postscript
eps
application/postscript
ps
application/rtf
rtf
application/set-payment-initiation
setpay
application/set-registration-initiation
setreg
application/vnd.ms-excel
xla
application/vnd.ms-excel
xlc
application/vnd.ms-excel
xlm
application/vnd.ms-excel
xls
application/vnd.ms-excel
xlt
application/vnd.ms-excel
xlw
application/vnd.ms-pkicertstore
sst
application/vnd.ms-pkiseccat
cat
application/vnd.ms-pkistl
stl
application/vnd.ms-powerpoint
pot,
application/vnd.ms-powerpoint
pps
application/vnd.ms-powerpoint
ppt
application/vnd.ms-project
mpp
application/vnd.ms-works
wcm
application/vnd.ms-works
wdb
application/vnd.ms-works
wks
application/vnd.ms-works
wps
application/winhlp
hlp
application/x-bcpio
bcpio
application/x-cdf
cdf
application/x-compress
z
application/x-compressed
tgz
application/x-cpio
cpio
application/x-csh
csh
application/x-director
dcr
application/x-director
dir
application/x-director
dxr
application/x-dvi
dvi
application/x-gtar
gtar
application/x-gzip
gz
application/x-hdf
hdf
application/x-internet-signup
ins
application/x-internet-signup
isp
application/x-iphone
iii
application/x-javascript
js
application/x-latex
latex
application/x-msaccess
mdb
application/x-mscardfile
crd
application/x-msclip
clp
application/x-msdownload
dll
application/x-msmediaview
m13
application/x-msmediaview
m14
application/x-msmediaview
mvb
application/x-msmetafile
wmf
application/x-msmoney
mny
application/x-mspublisher
pub
application/x-msschedule
scd
application/x-msterminal
trm
application/x-mswrite
wri
application/x-netcdf
cdf
application/x-netcdf
nc
application/x-perfmon
pma
application/x-perfmon
pmc
application/x-perfmon
pml
application/x-perfmon
pmr
application/x-perfmon
pmw
application/x-pkcs12
p12
application/x-pkcs12
pfx
application/x-pkcs7-certificates
p7b
application/x-pkcs7-certificates
spc
application/x-pkcs7-certreqresp
p7r
application/x-pkcs7-mime
p7c
application/x-pkcs7-mime
p7m
application/x-pkcs7-signature
p7s
application/x-sh
sh
application/x-shar
shar
application/x-stuffit
sit
application/x-sv4cpio
sv4cpio
application/x-sv4crc
sv4crc
application/x-tar
tar
application/x-tcl
tcl
application/x-tex
tex
application/x-texinfo
texi
application/x-texinfo
texinfo
application/x-troff
roff
application/x-troff
t
application/x-troff
tr
application/x-troff-man
man
application/x-troff-me
me
application/x-troff-ms
ms
application/x-ustar
ustar
application/x-wais-source
src
application/x-x509-ca-cert
cer
application/x-x509-ca-cert
crt
application/x-x509-ca-cert
der
application/ynd.ms-pkipko
pko
application/zip
zip
audio/basic
au
audio/basic
snd
audio/mid
mid
audio/mid
rmi
audio/mpeg
mp3
audio/x-aiff
aif
audio/x-aiff
aifc
audio/x-aiff
aiff
audio/x-mpegurl
m3u
audio/x-pn-realaudio
ra
audio/x-pn-realaudio
ram
audio/x-wav
wav
image/bmp
bmp
image/cis-cod
cod
image/gif
gif
image/ief
ief
image/jpeg
jpe
image/jpeg
jpeg
image/jpeg
jpg
image/pipeg
jfif
image/svg+xml
svg
image/tiff
tif
image/tiff
tiff
image/x-cmu-raster
ras
image/x-cmx
cmx
image/x-icon
ico
image/x-portable-anymap
pnm
image/x-portable-bitmap
pbm
image/x-portable-graymap
pgm
image/x-portable-pixmap
ppm
image/x-rgb
rgb
image/x-xbitmap
xbm
image/x-xpixmap
xpm
image/x-xwindowdump
xwd
message/rfc822
mht
message/rfc822
mhtml
message/rfc822
nws
text/css
css
text/h323
323
text/html
htm
text/html
html
text/html
stm
text/iuls
uls
text/plain
bas
text/plain
c
text/plain
h
text/plain
txt
text/richtext
rtx
text/scriptlet
sct
text/tab-separated-values
tsv
text/webviewhtml
htt
text/x-component
htc
text/x-setext
etx
text/x-vcard
vcf
video/mpeg
mp2
video/mpeg
mpa
video/mpeg
mpe
video/mpeg
mpeg
video/mpeg
mpg
video/mpeg
mpv2
video/quicktime
mov
video/quicktime
qt
video/x-la-asf
lsf
video/x-la-asf
lsx
video/x-ms-asf
asf
video/x-ms-asf
asr
video/x-ms-asf
asx
video/x-msvideo
avi
video/x-sgi-movie
movie
x-world/x-vrml
flr
x-world/x-vrml
vrml
x-world/x-vrml
wrl
x-world/x-vrml
wrz
x-world/x-vrml
xaf
x-world/x-vrml
xof
按照文件扩展名罗列的Mime类型
Extension 扩展名 |
Type/sub-type 类型/二级类型 |
application/octet-stream
323
text/h323
acx
application/internet-property-stream
ai
application/postscript
aif
audio/x-aiff
aifc
audio/x-aiff
aiff
audio/x-aiff
asf
video/x-ms-asf
asr
video/x-ms-asf
asx
video/x-ms-asf
au
audio/basic
avi
video/x-msvideo
axs
application/olescript
bas
text/plain
bcpio
application/x-bcpio
bin
application/octet-stream
bmp
image/bmp
c
text/plain
cat
application/vnd.ms-pkiseccat
cdf
application/x-cdf
cer
application/x-x509-ca-cert
class
application/octet-stream
clp
application/x-msclip
cmx
image/x-cmx
cod
image/cis-cod
cpio
application/x-cpio
crd
application/x-mscardfile
crl
application/pkix-crl
crt
application/x-x509-ca-cert
csh
application/x-csh
css
text/css
dcr
application/x-director
der
application/x-x509-ca-cert
dir
application/x-director
dll
application/x-msdownload
dms
application/octet-stream
doc
application/msword
dot
application/msword
dvi
application/x-dvi
dxr
application/x-director
eps
application/postscript
etx
text/x-setext
evy
application/envoy
exe
application/octet-stream
fif
application/fractals
flr
x-world/x-vrml
gif
image/gif
gtar
application/x-gtar
gz
application/x-gzip
h
text/plain
hdf
application/x-hdf
hlp
application/winhlp
hqx
application/mac-binhex40
hta
application/hta
htc
text/x-component
htm
text/html
html
text/html
htt
text/webviewhtml
ico
image/x-icon
ief
image/ief
iii
application/x-iphone
ins
application/x-internet-signup
isp
application/x-internet-signup
jfif
image/pipeg
jpe
image/jpeg
jpeg
image/jpeg
jpg
image/jpeg
js
application/x-javascript
latex
application/x-latex
lha
application/octet-stream
lsf
video/x-la-asf
lsx
video/x-la-asf
lzh
application/octet-stream
m13
application/x-msmediaview
m14
application/x-msmediaview
m3u
audio/x-mpegurl
man
application/x-troff-man
mdb
application/x-msaccess
me
application/x-troff-me
mht
message/rfc822
mhtml
message/rfc822
mid
audio/mid
mny
application/x-msmoney
mov
video/quicktime
movie
video/x-sgi-movie
mp2
video/mpeg
mp3
audio/mpeg
mpa
video/mpeg
mpe
video/mpeg
mpeg
video/mpeg
mpg
video/mpeg
mpp
application/vnd.ms-project
mpv2
video/mpeg
ms
application/x-troff-ms
mvb
application/x-msmediaview
nws
message/rfc822
oda
application/oda
p10
application/pkcs10
p12
application/x-pkcs12
p7b
application/x-pkcs7-certificates
p7c
application/x-pkcs7-mime
p7m
application/x-pkcs7-mime
p7r
application/x-pkcs7-certreqresp
p7s
application/x-pkcs7-signature
pbm
image/x-portable-bitmap
pdf
application/pdf
pfx
application/x-pkcs12
pgm
image/x-portable-graymap
pko
application/ynd.ms-pkipko
pma
application/x-perfmon
pmc
application/x-perfmon
pml
application/x-perfmon
pmr
application/x-perfmon
pmw
application/x-perfmon
pnm
image/x-portable-anymap
pot,
application/vnd.ms-powerpoint
ppm
image/x-portable-pixmap
pps
application/vnd.ms-powerpoint
ppt
application/vnd.ms-powerpoint
prf
application/pics-rules
ps
application/postscript
pub
application/x-mspublisher
qt
video/quicktime
ra
audio/x-pn-realaudio
ram
audio/x-pn-realaudio
ras
image/x-cmu-raster
rgb
image/x-rgb
rmi
audio/mid
roff
application/x-troff
rtf
application/rtf
rtx
text/richtext
scd
application/x-msschedule
sct
text/scriptlet
setpay
application/set-payment-initiation
setreg
application/set-registration-initiation
sh
application/x-sh
shar
application/x-shar
sit
application/x-stuffit
snd
audio/basic
spc
application/x-pkcs7-certificates
spl
application/futuresplash
src
application/x-wais-source
sst
application/vnd.ms-pkicertstore
stl
application/vnd.ms-pkistl
stm
text/html
svg
image/svg+xml
sv4cpio
application/x-sv4cpio
sv4crc
application/x-sv4crc
t
application/x-troff
tar
application/x-tar
tcl
application/x-tcl
tex
application/x-tex
texi
application/x-texinfo
texinfo
application/x-texinfo
tgz
application/x-compressed
tif
image/tiff
tiff
image/tiff
tr
application/x-troff
trm
application/x-msterminal
tsv
text/tab-separated-values
txt
text/plain
uls
text/iuls
ustar
application/x-ustar
vcf
text/x-vcard
vrml
x-world/x-vrml
wav
audio/x-wav
wcm
application/vnd.ms-works
wdb
application/vnd.ms-works
wks
application/vnd.ms-works
wmf
application/x-msmetafile
wps
application/vnd.ms-works
wri
application/x-mswrite
wrl
x-world/x-vrml
wrz
x-world/x-vrml
xaf
x-world/x-vrml
xbm
image/x-xbitmap
xla
application/vnd.ms-excel
xlc
application/vnd.ms-excel
xlm
application/vnd.ms-excel
xls
application/vnd.ms-excel
xlt
application/vnd.ms-excel
xlw
application/vnd.ms-excel
xof
x-world/x-vrml
xpm
image/x-xpixmap
xwd
image/x-xwindowdump
z
application/x-compress
zip
application/zip