MIME and Quoted-printable

关于MIME的介绍，from http://en.wikipedia.org/wiki/MIME

Multipurpose Internet Mail Extensions (MIME) is an Internet Standard that extends the format of e-mail to support:

• text in character sets other than US-ASCII;
• non-text attachments;
• multi-part message bodies; and
• header information in non-ASCII character sets.

Virtually all human-written Internet e-mail and a fairly large proportion of automated e-mail is transmitted via SMTP in MIME format. Internet e-mail is so closely associated with the SMTP and MIME standards that it is sometimes called SMTP/MIME e-mail.[1]

The content types defined by MIME standards are also of importance outside of e-mail, such as in communication protocols like HTTP for the World Wide Web. HTTP requires that data be transmitted in the context of e-mail-like messages, even though the data may not actually be e-mail.

MIME is specified in six RFCs: RFC 2045, RFC 2046, RFC 2047, RFC 4288, RFC 4289 and RFC 2077.

关于Quoted-printable的介绍，from http://en.wikipedia.org/wiki/Quoted-printable

Quoted-printable, or QP encoding, is an encoding using printable characters (i.e. alphanumeric and the equals sign "=") to transmit 8-bit data over a 7-bit data path. It is defined as a MIME content transfer encoding for use in Internet e-mail.

一些其它有用链接：

http://www.weiw.com/tech/luanma/luanma08.html
http://www.lupaworld.com/441/viewspace_220.html

我的分析，到http://www.motobit.com/util/quoted-printable-decoder.asp，提供在线的解码。输入：

<P>DearAmazonmember,<BR><BR>Duetoconcernswehaveforthesafetyand=
integrityoftheAmazoncommunitywehaveissuedthiswarning.<BR><BR>Per=
theUserAgreement,Section9,wemayimmediatelyissueawarning,tempor=
arilysuspend,indefinitelysuspendorterminateyourmembershipandrefus=
etoprovideourservicestoyouifwebelievethatyouractionsmaycause=
financiallossorlegalliabilityforyou,ourusersorus.Wemayalsot=
aketheseactionsifweareunabletoverifyorauthenticateanyinformati=
onyouprovidetous.<BR><BR>Pleasefollowthelinkbelow:<BR><BR><Ahre=
f=3D"http://rds.yahoo.com/_ylt=3DA0geurgnV4VEPnoB98hXNyoA;_ylu=3DX3oDMTE5a=
XJmaGJ2BGNvbG8DZQRsA1dTMQRwb3MDMTIzBHNlYwNzcgR2dGlkA0Y3NTFfMTA4/SIG=3D12hh=
jkhah/EXP=3D1149675687/**http://www.google.com/url?q=3Dhttp://211.94.240.2=
1/_us/obidos/index.html?ref=3Dpd_irl_gw_r/102-8758036-5777720?opt=3Doa&pag=
e=3Drecs/sign-in-secure.html&response=3Dtg/recs/recs-post"target=3D_BLANK=
>http://www.amazon.com/exec/obidos/sign-in.html</A><BR><BR>andupdateyour=
accountinformation.<BR><BR>Weappreciateyoursupportandunderstanding=
,asweworktogethertokeepAmazonmarketasafeplace.<BR><BR>Thankyo=
uforyourattentiononthisseriousmatter.</P>
<P><BR>Regards,<BR>AmazonSafetyDepartment<BR><BR><BR>NOTE:Thismessage=
wassenttoyoubyanautomatede-mailsystem.Pleasedon'treplytoit.A=
mazontreatsyourpersonalinformationwiththeutmostcare,andourPriva=
cyPolicyisdesignedtoprotectyouandyourinformation.</P><FONT
size=3D=
2></FONT><FONTface=3DArialsize=3D2>
<P>&nbsp;</P></FONT>

输出为：

<P>DearAmazonmember,<BR><BR>DuetoconcernswehaveforthesafetyandintegrityoftheAmazoncommunitywehaveissuedthiswarning.<BR><BR>PertheUserAgreement,Section9,wemayimmediatelyissueawarning,temporarilysuspend,indefinitelysuspendorterminateyourmembershipandrefusetoprovideourservicestoyouifwebelievethatyouractionsmaycausefinanciallossorlegalliabilityforyou,ourusersorus.Wemayalsotaketheseactionsifweareunabletoverifyorauthenticateanyinformationyouprovidetous.<BR><BR>Pleasefollowthelinkbelow:<BR><BR><Ahref="http://rds.yahoo.com/_ylt=A0geurgnV4VEPnoB98hXNyoA;_ylu=X3oDMTE5aXJmaGJ2BGNvbG8DZQRsA1dTMQRwb3MDMTIzBHNlYwNzcgR2dGlkA0Y3NTFfMTA4/SIG=12hhjkhah/EXP=1149675687/**http://www.google.com/url?q=http://211.94.240.21/_us/obidos/index.html?ref=pd_irl_gw_r/102-8758036-5777720?opt=oa&page=recs/sign-in-secure.html&response=tg/recs/recs-post"target=_BLANK>http://www.amazon.com/exec/obidos/sign-in.html</A><BR><BR>andupdateyouraccountinformation.<BR><BR>Weappreciateyoursupportandunderstanding,asweworktogethertokeepAmazonmarketasafeplace.<BR><BR>Thankyouforyourattentiononthisseriousmatter.</P>
<P><BR>Regards,<BR>AmazonSafetyDepartment<BR><BR><BR>NOTE:Thismessagewassenttoyoubyanautomatede-mailsystem.Pleasedon'treplytoit.Amazontreatsyourpersonalinformationwiththeutmostcare,andourPrivacyPolicyisdesignedtoprotectyouandyourinformation.</P><FONT
size=2></FONT><FONTface=Arialsize=2>
<P></P></FONT>

看看这里的URL，就是利用了URL Redirection。