add 'python' post processor

similar to 'exec' but calls a Python function

gallery_dl/postprocessor/__init__.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2018-2021 Mike Fährmann
+# Copyright 2018-2023 Mike Fährmann
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 as
@@ -14,6 +14,7 @@ modules = [
     "exec",
     "metadata",
     "mtime",
+    "python",
     "ugoira",
     "zip",
 ]

gallery_dl/postprocessor/python.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+
+# Copyright 2023 Mike Fährmann
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+"""Run Python functions"""
+
+from .common import PostProcessor
+from .. import util
+
+
+class PythonPP(PostProcessor):
+
+    def __init__(self, job, options):
+        PostProcessor.__init__(self, job)
+
+        spec = options["function"]
+        module_name, _, function_name = spec.rpartition(":")
+        module = util.import_file(module_name)
+        self.function = getattr(module, function_name)
+
+        self._init_archive(job, options)
+        if self.archive:
+            self.run = self.run_archive
+
+        events = options.get("event")
+        if events is None:
+            events = ("file",)
+        elif isinstance(events, str):
+            events = events.split(",")
+        job.register_hooks({event: self.run for event in events}, options)
+
+    def run(self, pathfmt):
+        self.function(pathfmt.kwdict)
+
+    def run_archive(self, pathfmt):
+        kwdict = pathfmt.kwdict
+        if self.archive.check(kwdict):
+            return
+        self.function(kwdict)
+        self.archive.add(kwdict)
+
+
+__postprocessor__ = PythonPP