Conform path length to filename scheme restriction

bdfr/file_name_formatter.py

@@ -27,6 +27,8 @@ class FileNameFormatter:
         "title",
         "upvotes",
     )
+    WINDOWS_MAX_PATH_LENGTH = 260
+    LINUX_MAX_PATH_LENGTH = 4096
 
     def __init__(
         self,
@@ -41,6 +43,10 @@ class FileNameFormatter:
         self.directory_format_string: list[str] = directory_format_string.split("/")
         self.time_format_string = time_format_string
         self.restiction_scheme = restriction_scheme.lower().strip() if restriction_scheme else None
+        if self.restiction_scheme == "windows":
+            self.max_path = self.WINDOWS_MAX_PATH_LENGTH
+        else:
+            self.max_path = self.find_max_path_length()
 
     def _format_name(self, submission: Union[Comment, Submission], format_string: str) -> str:
         if isinstance(submission, Submission):
@@ -63,6 +69,7 @@ class FileNameFormatter:
             if platform.system() == "Windows":
                 result = FileNameFormatter._format_for_windows(result)
         elif self.restiction_scheme == "windows":
+            logger.debug("Forcing Windows-compatible filenames")
             result = FileNameFormatter._format_for_windows(result)
         return result
 
@@ -135,14 +142,13 @@ class FileNameFormatter:
             raise BulkDownloaderException(f"Could not determine path name: {subfolder}, {index}, {resource.extension}")
         return file_path
 
-    @staticmethod
-    def limit_file_name_length(filename: str, ending: str, root: Path) -> Path:
+    def limit_file_name_length(self, filename: str, ending: str, root: Path) -> Path:
         root = root.resolve().expanduser()
         possible_id = re.search(r"((?:_\w{6})?$)", filename)
         if possible_id:
             ending = possible_id.group(1) + ending
             filename = filename[: possible_id.start()]
-        max_path = FileNameFormatter.find_max_path_length()
+        max_path = self.max_path
         max_file_part_length_chars = 255 - len(ending)
         max_file_part_length_bytes = 255 - len(ending.encode("utf-8"))
         max_path_length = max_path - len(ending) - len(str(root)) - 1
@@ -166,9 +172,9 @@ class FileNameFormatter:
             return int(subprocess.check_output(["getconf", "PATH_MAX", "/"]))
         except (ValueError, subprocess.CalledProcessError, OSError):
             if platform.system() == "Windows":
-                return 260
+                return FileNameFormatter.WINDOWS_MAX_PATH_LENGTH
             else:
-                return 4096
+                return FileNameFormatter.LINUX_MAX_PATH_LENGTH
 
     def format_resource_paths(
         self,

tests/test_file_name_formatter.py

@@ -33,6 +33,12 @@ def submission() -> MagicMock:
     return test
 
 
+@pytest.fixture()
+def test_formatter() -> FileNameFormatter:
+    out = FileNameFormatter("{TITLE}", "", "ISO")
+    return out
+
+
 def check_valid_windows_path(test_string: str):
     return test_string == FileNameFormatter._format_for_windows(test_string)
 
@@ -231,8 +237,8 @@ def test_format_multiple_resources():
         ("😍💕✨" * 100, "_1.png"),
     ),
 )
-def test_limit_filename_length(test_filename: str, test_ending: str):
-    result = FileNameFormatter.limit_file_name_length(test_filename, test_ending, Path("."))
+def test_limit_filename_length(test_filename: str, test_ending: str, test_formatter: FileNameFormatter):
+    result = test_formatter.limit_file_name_length(test_filename, test_ending, Path("."))
     assert len(result.name) <= 255
     assert len(result.name.encode("utf-8")) <= 255
     assert len(str(result)) <= FileNameFormatter.find_max_path_length()
@@ -253,8 +259,10 @@ def test_limit_filename_length(test_filename: str, test_ending: str):
         ("😍💕✨" * 100 + "_aaa1aa", "_1.png", "_aaa1aa_1.png"),
     ),
 )
-def test_preserve_id_append_when_shortening(test_filename: str, test_ending: str, expected_end: str):
-    result = FileNameFormatter.limit_file_name_length(test_filename, test_ending, Path("."))
+def test_preserve_id_append_when_shortening(
+    test_filename: str, test_ending: str, expected_end: str, test_formatter: FileNameFormatter
+):
+    result = test_formatter.limit_file_name_length(test_filename, test_ending, Path("."))
     assert len(result.name) <= 255
     assert len(result.name.encode("utf-8")) <= 255
     assert result.name.endswith(expected_end)
@@ -284,8 +292,8 @@ def test_shorten_filename_real(submission: MagicMock, tmp_path: Path):
         ("a" * 500, "_bbbbbb.jpg"),
     ),
 )
-def test_shorten_path(test_name: str, test_ending: str, tmp_path: Path):
-    result = FileNameFormatter.limit_file_name_length(test_name, test_ending, tmp_path)
+def test_shorten_path(test_name: str, test_ending: str, tmp_path: Path, test_formatter: FileNameFormatter):
+    result = test_formatter.limit_file_name_length(test_name, test_ending, tmp_path)
     assert len(str(result.name)) <= 255
     assert len(str(result.name).encode("UTF-8")) <= 255
     assert len(str(result.name).encode("cp1252")) <= 255
@@ -482,7 +490,9 @@ def test_get_max_path_length():
 def test_windows_max_path(tmp_path: Path):
     with unittest.mock.patch("platform.system", return_value="Windows"):
         with unittest.mock.patch("bdfr.file_name_formatter.FileNameFormatter.find_max_path_length", return_value=260):
-            result = FileNameFormatter.limit_file_name_length("test" * 100, "_1.png", tmp_path)
+            mock = MagicMock()
+            mock.max_path = 260
+            result = FileNameFormatter.limit_file_name_length(mock, "test" * 100, "_1.png", tmp_path)
             assert len(str(result)) <= 260
             assert len(result.name) <= (260 - len(str(tmp_path)))