Add cleantags plugin

beetsplug/cleantags.py

@@ -0,0 +1,42 @@
+from mutagen import File
+from beets.plugins import BeetsPlugin
+from beets.util.confit import ConfigValueError
+
+class CleanTagsPlugin(BeetsPlugin):
+
+    def __init__(self):
+        super(CleanTagsPlugin, self).__init__()
+        self.config.add({
+            'clean': True, # Whether to remove all tags before writing any new data.
+            'keep': [], # Tags to write to files.
+            'discard': [] # Tags to discard
+        })
+        self.register_listener('write', self.clear_metadata)
+            
+    @property
+    def clean(self):
+        return self.config['clean']
+    
+    @property
+    def keep_tags(self):
+        return self.config['keep'].as_str_seq()
+
+    @property
+    def discard_tags(self):
+        return self.config['discard'].as_str_seq()
+    
+    def clear_metadata(self, item, path, tags):
+        if self.keep_tags and self.discard_tags:
+            raise ConfigValueError('Cannot specify both "keep" and "discard" for cleantags plugin.')
+        if self.clean:
+            file = File(path)
+            file.delete()
+        
+        copy = tags.copy()
+        if self.keep_tags:
+            for tag in copy.keys():
+                if tag not in self.keep_tags:
+                    del tags[tag]
+        elif self.discard_tags:
+            for tag in self.discard_tags:
+                del tags[tag]