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diff --git a/users/sterni/mblog/note.lisp b/users/sterni/mblog/note.lisp
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+(in-package :mblog)
+(declaim (optimize (safety 3)))
+
+;;; util
+
+(defun html-escape-stream (in out)
+  "Escape characters read from stream IN and write them to
+  stream OUT escaped using WHO:ESCAPE-CHAR-MINIMAL."
+  (loop for char = (read-char in nil nil)
+        while char
+        do (write-string (who:escape-char-minimal char) out)))
+
+(defun cid-header-value (cid)
+  "Takes a Content-ID as present in Apple Notes' <object> tags and properly
+  surrounds them with angle brackets for a MIME header"
+  (concatenate 'string "<" cid ">"))
+
+;;; main implementation
+
+;; TODO(sterni): make this a “parser” instead of a predicate
+(defun apple-note-p (msg)
+  "Checks X-Uniform-Type-Identifier of a MIME:MIME-MESSAGE
+  to determine if a given mime message is an Apple Note."
+  (when-let (uniform-id (assoc "X-Uniform-Type-Identifier"
+                               (mime:mime-message-headers msg)
+                               :test #'string=))
+    (string= (cdr uniform-id) "com.apple.mail-note")))
+
+(defun apple-note-html-fragment (msg out)
+  "Takes a MIME:MIME-MESSAGE and writes its text content as HTML to
+  the OUT stream. The <object> tags are resolved to <img> which
+  refer to the respective attachment's filename as a relative path,
+  but extraction of the attachments must be done separately. The
+  surrounding <html> and <body> tags are stripped and <head>
+  discarded completely, so only a fragment which can be included
+  in custom templates remains."
+  (let ((text (find-mime-text-part msg)))
+    (cond
+      ;; Sanity checking of the note
+      ((not (apple-note-p msg))
+       (error "Unsupported or missing X-Uniform-Type-Identifier"))
+      ((not text) (error "Malformed Apple Note: no text part"))
+      ;; notemap creates text/plain notes we need to handle properly.
+      ;; Additionally we *could* check X-Mailer which notemap sets
+      ((string= (mime:mime-subtype text) "plain")
+       (html-escape-stream (mime:mime-body-stream text :binary nil) out))
+      ;; Notes.app creates text/html parts
+      ((string= (mime:mime-subtype text) "html")
+       (closure-html:parse
+        (mime:mime-body-stream text)
+        (make-instance
+         'apple-note-transformer
+         :cid-lookup
+         (lambda (cid)
+           (when-let* ((part (mime:find-mime-part-by-id msg (cid-header-value cid)))
+                       (file (mime:mime-part-file-name part)))
+             file))
+         :next-handler
+         (closure-html:make-character-stream-sink out))))
+      (t (error "Malformed Apple Note: unknown mime type")))))