Implement recursive metadata for FLAC files

Since FLAC files can contain covers, it makes sense
to parse their metadata

libmat2/audio.py

+import mimetypes
+import os
 import shutil
+import tempfile
 
 import mutagen
 
-from . import abstract
+from . import abstract, parser_factory
 
 
 class MutagenParser(abstract.AbstractParser):
@@ -55,6 +58,14 @@ class FLACParser(MutagenParser):
 
     def get_meta(self):
         meta = super().get_meta()
-        if mutagen.File(self.filename).pictures:
-            meta['Picture'] = 'Cover'
+        for num, picture in enumerate(mutagen.File(self.filename).pictures):
+            name = picture.desc if picture.desc else 'Cover %d' % num
+            _, fname = tempfile.mkstemp()
+            with open(fname, 'wb') as f:
+                f.write(picture.data)
+            extension = mimetypes.guess_extension(picture.mime)
+            shutil.move(fname, fname + extension)
+            p, _ = parser_factory.get_parser(fname+extension)
+            meta[name] = p.get_meta() if p else 'harmful data'
+            os.remove(fname + extension)
         return meta

mat2

@@ -65,25 +65,24 @@ def show_meta(filename: str):
     if p is None:
         print("[-] %s's format (%s) is not supported" % (filename, mtype))
         return
-    print("[+] Metadata for %s:" % filename)
-    metadata = p.get_meta().items() # type: dict
-    __print_meta(metadata)
+    __print_meta(filename, p.get_meta())
 
 
-def __print_meta(metadata: dict):
+def __print_meta(filename:str, metadata: dict, depth:int=1):
+    padding = " " * depth*2
     if not metadata:
-        print("  No metadata found")
+        print(padding + "No metadata found")
         return
 
-    for k, v in metadata:
+    print("[%s] Metadata for %s:" % ('+'*depth, filename))
+
+    for k, v in metadata.items():
         if isinstance(v, dict):
-            __print_meta(v)
-        else:
-            try:  # FIXME this is ugly.
-                print("  %s: %s" % (k, v))
-            except UnicodeEncodeError:
-                print("  %s: harmful content" % k)
-    return
+            return __print_meta(k, v, depth+1)
+        try:  # FIXME this is ugly.
+            print(padding + "  %s: %s" % (k, v))
+        except UnicodeEncodeError:
+            print(padding + "  %s: harmful content" % k)
 
 
 def clean_meta(filename: str, is_lightweight: bool, policy: UnknownMemberPolicy) -> bool:

tests/test_libmat2.py

@@ -96,7 +96,7 @@ class TestGetMeta(unittest.TestCase):
         p = audio.FLACParser('./tests/data/dirty.flac')
         meta = p.get_meta()
         self.assertEqual(meta['title'], 'I am so')
-        self.assertEqual(meta['Picture'], 'Cover')
+        self.assertEqual(meta['Cover 0'], {'Comment': 'Created with GIMP'})
 
     def test_docx(self):
         p = office.MSOfficeParser('./tests/data/dirty.docx')