db/attachment: simplify the Attachment class

Make it a plain container around raw data and a few bits of metadata,
rather than around a whole MIME part.

1 files changed, 30 insertions, 79 deletions

diff --git a/alot/mail/envelope.py b/alot/mail/envelope.py
index 5a798f19..540c0342 100644
--- a/alot/mail/envelope.py
+++ b/alot/mail/envelope.py
@@ -7,12 +7,7 @@ import os
 import re
 import email
 import email.policy
-from email.encoders import encode_7or8bit
 from email.message import MIMEPart
-from email.mime.audio import MIMEAudio
-from email.mime.base import MIMEBase
-from email.mime.image import MIMEImage
-from email.mime.text import MIMEText
 import email.charset as charset
 from urllib.parse import unquote
 
@@ -85,57 +80,6 @@ def _guess_encoding(blob):
     else:
         raise Exception('Unknown magic API')
 
-# TODO: make this work on blobs, not paths
-def _mimewrap(path, filename, ctype):
-    """Take the contents of the given path and wrap them into an email MIME
-    part according to the content type.  The content type is auto detected from
-    the actual file contents and the file name if it is not given.
-
-    :param path: the path to the file contents
-    :type path: str
-    :param filename: the file name to use in the generated MIME part
-    :type filename: str or None
-    :param ctype: the content type of the file contents in path
-    :type ctype: str or None
-    :returns: the message MIME part storing the data from path
-    :rtype: subclasses of email.mime.base.MIMEBase
-    """
-
-    with open(path, 'rb') as f:
-        content = f.read()
-    if not ctype:
-        ctype = helper.guess_mimetype(content)
-        # libmagic < 5.12 incorrectly detects excel/powerpoint files as
-        # 'application/msword' (see #179 and #186 in libmagic bugtracker)
-        # This is a workaround, based on file extension, useful as long
-        # as distributions still ship libmagic 5.11.
-        if (ctype == 'application/msword' and
-            not _libmagic_version_at_least(513)):
-            mimetype, _ = mimetypes.guess_type(path)
-            if mimetype:
-                ctype = mimetype
-
-    maintype, subtype = ctype.split('/', 1)
-    if maintype == 'text':
-        part = MIMEText(content.decode(_guess_encoding(content), 'replace'),
-                        _subtype=subtype,
-                        _charset='utf-8')
-    elif maintype == 'image':
-        part = MIMEImage(content, _subtype=subtype)
-    elif maintype == 'audio':
-        part = MIMEAudio(content, _subtype=subtype)
-    else:
-        part = MIMEBase(maintype, subtype)
-        part.set_payload(content)
-        # Encode the payload using Base64
-        email.encoders.encode_base64(part)
-    # Set the filename parameter
-    if not filename:
-        filename = os.path.basename(path)
-    part.add_header('Content-Disposition', 'attachment',
-                    filename=filename)
-    return part
-
 class Envelope:
     """
     a message that is not yet sent and still editable.
@@ -263,28 +207,37 @@ class Envelope:
         if self.sent_time:
             self.modified_since_sent = True
 
-    def attach(self, attachment, filename=None, ctype=None):
+    def attach_file(self, path, filename = None):
+        with open(path, 'rb') as f:
+            data = f.read()
+
+        ctype = helper.guess_mimetype(data)
+        # libmagic < 5.12 incorrectly detects excel/powerpoint files as
+        # 'application/msword' (see #179 and #186 in libmagic bugtracker)
+        # This is a workaround, based on file extension, useful as long
+        # as distributions still ship libmagic 5.11.
+        if (ctype == 'application/msword' and
+            not _libmagic_version_at_least(513)):
+            mimetype, _ = mimetypes.guess_type(path)
+            if mimetype:
+                ctype = mimetype
+
+        # Set the filename parameter
+        if not filename:
+            filename = os.path.basename(path)
+
+        attachment = Attachment(data, ctype, filename, ())
+        self.attach(attachment)
+
+    def attach(self, attachment):
         """
         attach a file
 
         :param attachment: File to attach, given as
-            :class:`~alot.db.attachment.Attachment` object or path to a file.
-        :type attachment: :class:`~alot.db.attachment.Attachment` or str
-        :param filename: filename to use in content-disposition.
-            Will be ignored if `path` matches multiple files
-        :param ctype: force content-type to be used for this attachment
-        :type ctype: str
+            :class:`~alot.db.attachment.Attachment` object
+        :type attachment: :class:`~alot.db.attachment.Attachment`
         """
-
-        if isinstance(attachment, Attachment):
-            self.attachments.append(attachment)
-        elif isinstance(attachment, str):
-            path = os.path.expanduser(attachment)
-            part = _mimewrap(path, filename, ctype)
-            self.attachments.append(Attachment(part))
-        else:
-            raise TypeError('attach accepts an Attachment or str')
-
+        self.attachments.append(attachment)
         if self.sent_time:
             self.modified_since_sent = True
 
@@ -305,11 +258,9 @@ class Envelope:
 
         # add attachments
         for a in self.attachments:
-            maintype, _, subtype = a.get_content_type().partition('/')
-            fname                = a.get_filename()
-            data                 = a.get_data()
-            mail.add_attachment(data, filename = fname,
-                                maintype = maintype, subtype = subtype)
+            mail.add_attachment(a.data, filename = a.filename,
+                                maintype = a.content_maintype,
+                                subtype  = a.content_subtype)
 
         if self.sign:
             to_sign = mail
@@ -456,7 +407,7 @@ class Envelope:
                                   if os.path.isfile(g)]
                 logging.debug('Attaching: %s', to_attach)
                 for path in to_attach:
-                    self.attach(path)
+                    self.attach_file(path)
                 del self['Attach']
 
         self.body = raw[headerEndPos:].strip()