[postprocessor:metadata] implement 'mode: delete' (#2640)

docs/configuration.rst

@@ -3319,6 +3319,7 @@ Description
     * ``"tags"``: ``tags`` separated by newlines
     * ``"custom"``: result of applying `metadata.content-format`_
       to a file's metadata dictionary
+    * ``"delete"``: remove metadata entries specified in `metadata.fields`_
 
 
 metadata.filename
@@ -3407,6 +3408,16 @@ Description
         e.g. a Tweet on Twitter or a post on Patreon.
 
 
+metadata.fields
+---------------
+Type
+    ``list`` of ``strings``
+Example
+    ``["blocked", "watching", "status[creator][name]"]``
+Description
+    List of metadata field names to remove for ``"mode": "delete"``.
+
+
 metadata.content-format
 -----------------------
 Type

gallery_dl/postprocessor/metadata.py

@@ -30,6 +30,10 @@ class MetadataPP(PostProcessor):
         elif mode == "tags":
             self.write = self._write_tags
             ext = "txt"
+        elif mode == "delete":
+            self.run = self._run_delete
+            self.fields = options.get("fields")
+            ext = None
         else:
             self.write = self._write_json
             self.indent = options.get("indent", 4)
@@ -114,6 +118,19 @@ class MetadataPP(PostProcessor):
     def _run_stdout(self, pathfmt):
         self.write(sys.stdout, pathfmt.kwdict)
 
+    def _run_delete(self, pathfmt):
+        kwdict = pathfmt.kwdict
+        for key in self.fields:
+            obj = kwdict
+            try:
+                while "[" in key:
+                    name, _, key = key.partition("[")
+                    obj = obj[name]
+                    key = key.rstrip("]")
+                del obj[key]
+            except Exception:
+                pass
+
     def _directory(self, pathfmt):
         return pathfmt.realdirectory
 

test/test_postprocessor.py

@@ -339,6 +339,28 @@ class MetadataTest(BasePostprocessorTest):
 {"category": "test", "extension": "ext", "filename": "file"}
 """)
 
+    def test_metadata_delete(self):
+        kwdict = {"foo": 0, "bar": {"bax": 1, "bay": 2, "baz": 3}}
+        self._create({"mode": "delete", "fields": ["foo", "bar[baz]"]}, kwdict)
+        pdict = self.pathfmt.kwdict
+
+        self.assertEqual(pdict["foo"], kwdict["foo"])
+        self.assertEqual(pdict["bar"], kwdict["bar"])
+
+        self.assertIsNot(kwdict, pdict)
+        del kwdict["foo"]
+        del kwdict["bar"]["baz"]
+
+        self._trigger()
+        self.assertNotIn("foo", pdict)
+        self.assertNotIn("baz", pdict["bar"])
+        self.assertEqual(kwdict["bar"], pdict["bar"])
+
+        self._trigger()
+        self.assertNotIn("foo", pdict)
+        self.assertNotIn("baz", pdict["bar"])
+        self.assertEqual(kwdict["bar"], pdict["bar"])
+
     @staticmethod
     def _output(mock):
         return "".join(