support 'filter' option for post processors (#1460)

docs/configuration.rst

@@ -2936,11 +2936,17 @@ Example
             "name"       : "zip",
             "compression": "store",
             "extension"  : "cbz",
+            "filter"     : "extension not in ('zip', 'rar')",
             "whitelist"  : ["mangadex", "exhentai", "nhentai"]
         }
 Description
     An ``object`` containing a ``"name"`` attribute specifying the
     post-processor type, as well as any of its `options <Postprocessor Options_>`__.
+
+    It is possible to set a ``"filter"`` expression similar to
+    `image-filter <extractor.*.image-filter_>`_ to only run a post-processor
+    condionally.
+
     It is also possible set a ``"whitelist"`` or ``"blacklist"`` to
     only enable or disable a post-processor for the specified
     extractor categories.

gallery_dl/job.py

@@ -12,6 +12,7 @@ import time
 import errno
 import logging
 import operator
+import functools
 import collections
 from . import extractor, downloader, postprocessor
 from . import config, text, util, output, exception
@@ -459,6 +460,23 @@ class DownloadJob(Job):
                     for callback in self.hooks["init"]:
                         callback(pathfmt)
 
+    def register_hooks(self, hooks, options=None):
+        expr = options.get("filter") if options else None
+
+        if expr:
+            condition = util.compile_expression(expr)
+            for hook, callback in hooks.items():
+                self.hooks[hook].append(functools.partial(
+                    self._call_hook, callback, condition))
+        else:
+            for hook, callback in hooks.items():
+                self.hooks[hook].append(callback)
+
+    @staticmethod
+    def _call_hook(callback, condition, pathfmt):
+        if condition(pathfmt.kwdict):
+            callback(pathfmt)
+
     def _build_blacklist(self):
         wlist = self.extractor.config("whitelist")
         if wlist is not None:

gallery_dl/postprocessor/classify.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2018-2020 Mike Fährmann
+# Copyright 2018-2021 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
@@ -31,9 +31,8 @@ class ClassifyPP(PostProcessor):
             for directory, exts in mapping.items()
             for ext in exts
         }
-
-        job.hooks["prepare"].append(self.prepare)
-        job.hooks["file"].append(self.move)
+        job.register_hooks(
+            {"prepare": self.prepare, "file": self.move}, options)
 
     def prepare(self, pathfmt):
         ext = pathfmt.extension

gallery_dl/postprocessor/compare.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2020 Mike Fährmann
+# Copyright 2020-2021 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
@@ -18,11 +18,12 @@ class ComparePP(PostProcessor):
         PostProcessor.__init__(self, job)
         if options.get("shallow"):
             self._compare = self._compare_size
-        job.hooks["file"].append(
+
+        job.register_hooks({"file": (
             self.enumerate
             if options.get("action") == "enumerate" else
             self.compare
-        )
+        )}, options)
 
     def compare(self, pathfmt):
         try:

gallery_dl/postprocessor/exec.py

@@ -41,8 +41,7 @@ class ExecPP(PostProcessor):
             events = ("after",)
         elif isinstance(events, str):
             events = events.split(",")
-        for event in events:
-            job.hooks[event].append(execute)
+        job.register_hooks({event: execute for event in events}, options)
 
     def exec_list(self, pathfmt, status=None):
         if status:

gallery_dl/postprocessor/metadata.py

@@ -57,8 +57,7 @@ class MetadataPP(PostProcessor):
             events = ("file",)
         elif isinstance(events, str):
             events = events.split(",")
-        for event in events:
-            job.hooks[event].append(self.run)
+        job.register_hooks({event: self.run for event in events}, options)
 
     def run(self, pathfmt):
         directory = self._directory(pathfmt)

gallery_dl/postprocessor/mtime.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2019-2020 Mike Fährmann
+# Copyright 2019-2021 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
@@ -17,7 +17,7 @@ class MtimePP(PostProcessor):
     def __init__(self, job, options):
         PostProcessor.__init__(self, job)
         self.key = options.get("key", "date")
-        job.hooks["file"].append(self.run)
+        job.register_hooks({"file": self.run}, options)
 
     def run(self, pathfmt):
         mtime = pathfmt.kwdict.get(self.key)

gallery_dl/postprocessor/ugoira.py

@@ -55,8 +55,8 @@ class UgoiraPP(PostProcessor):
         else:
             self.prevent_odd = False
 
-        job.hooks["prepare"].append(self.prepare)
-        job.hooks["file"].append(self.convert)
+        job.register_hooks(
+            {"prepare": self.prepare, "file": self.convert}, options)
 
     def prepare(self, pathfmt):
         self._frames = None

gallery_dl/postprocessor/zip.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright 2018-2020 Mike Fährmann
+# Copyright 2018-2021 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
@@ -38,9 +38,11 @@ class ZipPP(PostProcessor):
         self.args = (self.path[:-1] + ext, "a",
                      self.COMPRESSION_ALGORITHMS[algorithm], True)
 
-        job.hooks["file"].append(
-            self.write_safe if options.get("mode") == "safe" else self.write)
-        job.hooks["finalize"].append(self.finalize)
+        job.register_hooks({
+            "file":
+            self.write_safe if options.get("mode") == "safe" else self.write,
+            "finalize": self.finalize,
+        }, options)
 
     def write(self, pathfmt, zfile=None):
         # 'NameToInfo' is not officially documented, but it's available

test/test_postprocessor.py

@@ -37,6 +37,10 @@ class FakeJob():
         self.get_logger = logging.getLogger
         self.hooks = collections.defaultdict(list)
 
+    def register_hooks(self, hooks, options):
+        for hook, callback in hooks.items():
+            self.hooks[hook].append(callback)
+
 
 class TestPostprocessorModule(unittest.TestCase):