New plugin?

config.yaml

@@ -1,17 +1,22 @@
 plugins:
-  fetchart
-  lastgenre
-  edit
-  fromfilename
-  missing
   inline
-  playlist
-  smartplaylist
+  info
+  fetchart
+  edit
   duplicates
   mbsync
+  lastgenre
+  missing
+  playlist
+  smartplaylist
+  fromfilename
+  beetslabels
   # extrafiles
   # chromaprint
 
+pluginpath:
+  - /home/benson/.config/beets/plugins
+
 directory: /home/benson/Music
 library: /home/benson/Music/library.db
 

plugins/beetslabels.py

@@ -0,0 +1,106 @@
+from beets import ui
+from beets.plugins import BeetsPlugin
+from beets.ui import Subcommand, print_
+from beets.ui.commands import print_and_modify
+
+from beets.dbcore import types
+from beets.dbcore import FieldQuery
+
+import optparse
+
+import json
+
+def do_modify_labels(lib, objs, label, action):
+    changed = []
+
+    for obj in objs:
+        labels = []
+        if action != 2:
+            if "mylabels" in obj:
+                labels = json.loads(obj["mylabels"])
+
+            if action == 0:
+                labels.append(label)
+                labels = sorted(set(labels))
+            elif label in labels:
+                labels.remove(label)
+
+        obj_mods = {
+            "mylabels": json.dumps(labels)
+        }
+        if print_and_modify(obj, obj_mods, []) and obj not in changed:
+            changed.append(obj)
+
+    # Still something to do?
+    if not changed:
+        print_("No changes to make.")
+        return
+
+    # Confirm action.
+    changed = ui.input_select_objects(
+        "Really modify",
+        changed,
+        lambda o: print_and_modify(o, mods, dels),
+    )
+
+    # Apply changes to database and files
+    with lib.transaction():
+        for obj in changed:
+            obj.try_sync(True, False, False)
+
+action_map = {
+    "add": 0,
+    "remove": 1,
+    "removeall": 2,
+    "show": 3
+}
+
+def modify_labels(lib, opts, args):
+    action = args[0]
+
+    if action not in action_map:
+        print_("%s is not a valid action. " % action)
+        print_("Valid actions are: add, remove, removeall, show")
+        return
+
+    actnum = action_map[action]
+
+    if actnum >= 2:
+        label = None
+        query = args[1:]
+    else:
+        label = args[1]
+        query = args[2:]
+
+    items = lib.items(query=query)
+
+    if actnum == 3:
+        for obj in items:
+            print_(obj.title)
+            if "mylabels" in obj:
+                print_("  " + "; ".join(obj["mylabels"]))
+    else:
+        do_modify_labels(lib, items, label, actnum)
+
+labels_command = Subcommand('labels', help='Add or remove labels')
+labels_command.func = modify_labels
+
+class JSONHas(FieldQuery):
+    @classmethod
+    def value_match(self, pattern, val):
+        if val is not None:
+            labels = json.loads(val)
+            return pattern in labels
+        return False
+
+class BeetsLabelsPlugin(BeetsPlugin):
+    # item_queries = { 'has_label': DelimitedHasExact }
+    # item_types = {'mylabels': types.SEMICOLON_SPACE_DSV}
+
+    def queries(self):
+        return {
+            "JSON@" : JSONHas
+        }
+
+    def commands(self):
+        return [labels_command]