[mel-base-devel] Saving and finding attachments

[Fred Gibson]

I've written a function to save an attachment:

(defun save-attachment-file (part filename)
  (let* ((attach (mel.mime:part-body-string part))
         (length (length
                  (string-trim '(#\newline #\return #\linefeed)
                               (read-line (make-string-input-stream attach)))))
         (in (make-string-input-stream attach)))
    (with-open-file (out filename :direction :output :element-type
'(unsigned-byte 8))
      (loop with buffer = (make-array length :element-type 'character)
         for count = (read-sequence buffer in)
         while (> count 0)
         do (write-sequence (mel.mime::decode-base64 buffer) out)
           (flet ((peek ()(peek-char nil in nil :eof))
                  (consume () (read-char in nil :eof)))
             (tagbody
              start (let ((c (peek)))
                      (when (member c '(#\return #\linefeed #\newline))
                        (progn (consume) (go start))))))))))

and for finding attachments in a message:

(defun find-attachments (eml)
  (flet ((eml-mixed? (e)
           (multiple-value-bind (a b c) (mel.mime:content-type e)
             (declare (ignore a c))
             (when (eq b :mixed) t)))
         (eml-part-base64? (part)
           (when (eq (mel.mime:content-transfer-encoding part) :base64)
             t)))
  (when (eml-mixed? eml)
    (let (attach)
      (dolist (part (mel:parts eml))
        (when (eml-part-base64? part)
          (push part attach)))
      attach))))


-- 
Fred Gibson

Founder / Software Developer
http://www.streamfocus.com

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