Fix guess_encoding()

Turns out commit 7a9da3b0f obliterated a difference that mattered - the
different argument to magic.open() in guess_mimetype() and guess_encoding()

This commit reinstates that difference, and has a correct use of the pip
python-magic library to get the encoding.

1 files changed, 23 insertions, 3 deletions

diff --git a/alot/helper.py b/alot/helper.py
index 20068ca7..e1fbdabe 100644
--- a/alot/helper.py
+++ b/alot/helper.py
@@ -375,7 +375,26 @@ def guess_mimetype(blob):
     :rtype: str
     """
     mimetype = 'application/octet-stream'
-    magictype = guess_encoding(blob)
+    # this is a bit of a hack to support different versions of python magic.
+    # Hopefully at some point this will no longer be necessary
+    #
+    # the version with open() is the bindings shipped with the file source from
+    # http://darwinsys.com/file/ - this is what is used by the python-magic
+    # package on Debian/Ubuntu.  However it is not available on pypi/via pip.
+    #
+    # the version with from_buffer() is from https://github.com/ahupp/python-magic
+    # which is installable via pip.
+    #
+    # for more detail see https://github.com/pazz/alot/pull/588
+    if hasattr(magic, 'open'):
+        m = magic.open(magic.MAGIC_MIME_TYPE)
+        m.load()
+        magictype = m.buffer(blob)
+    elif hasattr(magic, 'from_buffer'):
+        magictype = magic.from_buffer(blob, mime=True)
+    else:
+        raise Exception('Unknown magic API')
+
     # libmagic does not always return proper mimetype strings, cf. issue #459
     if re.match(r'\w+\/\w+', magictype):
         mimetype = magictype
@@ -403,11 +422,12 @@ def guess_encoding(blob):
     #
     # for more detail see https://github.com/pazz/alot/pull/588
     if hasattr(magic, 'open'):
-        m = magic.open(magic.MAGIC_MIME_TYPE)
+        m = magic.open(magic.MAGIC_MIME_ENCODING)
         m.load()
         return m.buffer(blob)
     elif hasattr(magic, 'from_buffer'):
-        return magic.from_buffer(blob, mime=True)
+        m = magic.Magic(mime_encoding=True)
+        return m.from_buffer(blob)
     else:
         raise Exception('Unknown magic API')