[Email-SIG] Converting to quoted printable encoding

[Mark Sapiro]

Nicholas Cole wrote:

>On Wed, Sep 24, 2008 at 8:25 PM, Nicholas Cole <nicholas.cole at gmail.com> wrote:
>> My naive attempt to convert a MIMEText message part to quoted
>> printable (having read the documentation) looked something like this:
>>
>> E = email.mime.text.MIMEText("This is some text")
>> email.encoders.encode_quopri(E)
>> print E.as_string()
>>
>> But it yields a message with two Content-Transfer-Encoding headers.


We do

E = email.mime.text.MIMEText("This is some text")
del E.['content-transfer_encoding']
email.encoders.encode_quopri(E)



>> I'm assuming that this is not a bug - but what is "The Right Way"(TM)
>> to change the encoding of text?
>
>I can't see that this isn't a bug - in that encode_quopri is (as the
>documentation says) adding a header, but not replacing the one that
>was there already.
>
>But I am confused.  Doing this results in a truly mangled message,
>suggesting that encode_quopri is not as aware of existing encoding as
>I thought:
>
>E = email.mime.text.MIMEText("This is some text")
>email.encoders.encode_quopri(E)
>email.encoders.encode_quopri(E)



Yes, doubly encoding the payload will result in a payload that has to
be doubly decoded.

I suppose the ideal solution to all of this is that the encoder should
first look at the existing Content-Transfer_Encoding header if any to
see if the payload is already encoded, and if no header, encode and
add the header; if existing header with target encoding, do nothing,
and if existing header with other encoding, decode, encode and replace
the header. However it doesn't work that way.


>So, it looks like I'm going to be better off using the quopri module directly...


Consider this

email.Charset.add_charset('us-ascii', body_enc=email.Charset.QP)
E = email.mime.text.MIMEText("This is some text")
print E.as_string()


-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan