implement conditional directories (#1394)

They work the same way as conditional filenames (84d2e640), e.g.

"directory": {
    "score >= 20": ["high score"],
    "score >= 5" : ["mid score"],
    ""           : ["{category}", "default"]
}

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Changelog
 
+## Unreleased
+
 ## 1.18.0 - 2021-06-19
 ### Additions
 - [foolfuuka] support `archive.wakarimasen.moe` ([#1595](https://github.com/mikf/gallery-dl/issues/1595))

docs/configuration.rst

@@ -60,7 +60,7 @@ extractor.*.filename
 Type
     ``string`` or ``object``
 Example
-    * .. code::
+    * .. code:: json
 
         "{manga}_c{chapter}_{page:>03}.{extension}"
 
@@ -115,11 +115,25 @@ Description
 extractor.*.directory
 ---------------------
 Type
-    ``list`` of ``strings``
+    ``list`` of ``strings`` or ``object``
 Example
-    ``["{category}", "{manga}", "c{chapter} - {title}"]``
+    * .. code:: json
+
+        ["{category}", "{manga}", "c{chapter} - {title}"]
+
+    * .. code:: json
+
+        {
+            "'nature' in content": ["Nature Pictures"],
+            "retweet_id != 0"    : ["{category}", "{user[name]}", "Retweets"],
+            ""                   : ["{category}", "{user[name]}"]
+        }
+
 Description
-    A list of `format strings`_ for the resulting target directory.
+    A list of `format strings`_ to build target directory paths with.
+
+    If this is an ``object``, it must contain Python expressions mapping to the
+    list of format strings to use.
 
     Each individual string in such a list represents a single path
     segment, which will be joined together and appended to the

gallery_dl/util.py

@@ -777,9 +777,20 @@ class PathFormat():
             raise exception.FilenameFormatError(exc)
 
         directory_fmt = config("directory")
-        if directory_fmt is None:
-            directory_fmt = extractor.directory_fmt
         try:
+            if directory_fmt is None:
+                directory_fmt = extractor.directory_fmt
+            elif isinstance(directory_fmt, dict):
+                self.directory_conditions = [
+                    (compile_expression(expr), [
+                        Formatter(fmt, kwdefault).format_map
+                        for fmt in fmts
+                    ])
+                    for expr, fmts in directory_fmt.items() if expr
+                ]
+                self.build_directory = self.build_directory_conditional
+                directory_fmt = directory_fmt.get("", extractor.directory_fmt)
+
             self.directory_formatters = [
                 Formatter(dirfmt, kwdefault).format_map
                 for dirfmt in directory_fmt
@@ -870,29 +881,14 @@ class PathFormat():
     def set_directory(self, kwdict):
         """Build directory path and create it if necessary"""
         self.kwdict = kwdict
-
-        # Build path segments by applying 'kwdict' to directory format strings
-        segments = []
-        append = segments.append
-        try:
-            for formatter in self.directory_formatters:
-                segment = formatter(kwdict).strip()
-                if WINDOWS:
-                    # remove trailing dots and spaces (#647)
-                    segment = segment.rstrip(". ")
-                if segment:
-                    append(self.clean_segment(segment))
-        except Exception as exc:
-            raise exception.DirectoryFormatError(exc)
-
-        # Join path segments
         sep = os.sep
-        directory = self.clean_path(self.basedirectory + sep.join(segments))
 
-        # Ensure 'directory' ends with a path separator
+        segments = self.build_directory(kwdict)
         if segments:
-            directory += sep
-        self.directory = directory
+            self.directory = directory = self.clean_path(
+                self.basedirectory + sep.join(segments) + sep)
+        else:
+            self.directory = directory = self.clean_path(self.basedirectory)
 
         if WINDOWS:
             # Enable longer-than-260-character paths on Windows
@@ -956,6 +952,43 @@ class PathFormat():
         except Exception as exc:
             raise exception.FilenameFormatError(exc)
 
+    def build_directory(self, kwdict):
+        """Apply 'kwdict' to directory format strings"""
+        segments = []
+        append = segments.append
+
+        try:
+            for formatter in self.directory_formatters:
+                segment = formatter(kwdict).strip()
+                if WINDOWS:
+                    # remove trailing dots and spaces (#647)
+                    segment = segment.rstrip(". ")
+                if segment:
+                    append(self.clean_segment(segment))
+            return segments
+        except Exception as exc:
+            raise exception.DirectoryFormatError(exc)
+
+    def build_directory_conditional(self, kwdict):
+        segments = []
+        append = segments.append
+
+        try:
+            for condition, formatters in self.directory_conditions:
+                if condition(kwdict):
+                    break
+            else:
+                formatters = self.directory_formatters
+            for formatter in formatters:
+                segment = formatter(kwdict).strip()
+                if WINDOWS:
+                    segment = segment.rstrip(". ")
+                if segment:
+                    append(self.clean_segment(segment))
+            return segments
+        except Exception as exc:
+            raise exception.DirectoryFormatError(exc)
+
     def build_path(self):
         """Combine directory and filename to full paths"""
         if self._create_directory:

gallery_dl/version.py

@@ -6,4 +6,4 @@
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
 
-__version__ = "1.18.0"
+__version__ = "1.18.1-dev"