[mel-base-devel] multipart messages and pop3

[Timothy Ritchey]

Thank you. I was getting the sense that it was hanging waiting on  
something from the server, so your suggestion of pulling into a local  
maildir makes sense, and gives me a direction to push.

On a side note, is there a way to detect whether a text body needs  
decode-quoted-printable run on it? Right now I naively run it on every  
message, and then just fallback to the raw text if it fails.

- T


On Apr 16, 2009, at 9:52 AM, Jochen Schmidt wrote:

> Am 16.04.2009 um 14:28 schrieb Timothy Ritchey <tritchey at mac.com>:
>
>> I'm having an issue extracting the parts of messages, particularly
>> when trying to work with pop3 folders. I am wondering if I am doing
>> something wrong. I am trying to extract any text/plain, or text/plain
>> alternative from emails. The following works when I pass it an imaps
>> folder, but mel:parts hangs when I pass it a pop3 folder. When I  
>> break
>> it, it is hanging out in compute-bodystructure-using-folder, waiting
>> on a stream.
>>
>> Am I grabbing messages the right way?
>
> It could well be a bug - I've not tested it, but actually it may be  
> a better idea to fetch the messages from the POP3 server into a  
> local maildir folder and then use that for further processing. POP3  
> is quite braindead and doesn't really lean to well accessing  
> messages randomly. Due to the lazy caching nature of mel-base there  
> would probably be multiple fetches of a single mail in POP3.
>
> What you try to do seems to be what mel-base does in FIND-VIEWABLE- 
> PART (see multiparts.lisp).
>
> ciao
> Jochen
>
>>
>> (defun find-plain-text (message)
>>  (let ((parts (mel:parts message))
>>   (body "Unable to process email contents"))
>>    (dolist (p parts)
>>      (multiple-value-bind (a b) (mel:content-type p)
>>   (if (and (equal a :TEXT) (equal b :PLAIN))
>>       (let ((b (mel:part-body-string p)))
>>         (handler-case
>>         (setf body (mel:decode-quoted-printable b))
>>       (t ()
>>         (setf body b))))
>>     (progn
>>       (when (and (equal a :MULTIPART) (equal b :ALTERNATIVE))
>>         (find-plain-text p))))))
>>    body))
>>
>> (defun check-email (folder)
>>  (let* ((messages (mel:messages folder)))
>>    (dolist (message messages)
>>      (format t "~a~%" (find-plain-text message)))))
>>
>> I can call the following on the same message from the pop3 folder,  
>> and
>> get the raw contents fine.
>>
>> (defmethod body (message)
>>  (with-output-to-string (str)
>>    (with-open-stream (stream (mel:message-body-stream message))
>>      (loop for c = (read-char stream nil nil)
>>    while c do (write-char c str)))))
>>
>> Any help would be appreciated.
>>
>> - T
>>
>>
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>
> --
> Jochen Schmidt
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