fix: add support for long filenames on export

* Fix for file names that are too long for file system
* Improved fix for long file names

evernote_backup/note_exporter_util.py

@@ -2,6 +2,9 @@
 from typing import Dict
 
 
+MAX_FILE_NAME_LEN = 255
+
+
 class SafePath(object):
     """Ensures path for tuples of directory names that may contain bad symbols
 
@@ -65,9 +68,39 @@ def _replace_bad_characters(string: str) -> str:
 
 
 def _get_non_existant_name(safe_name: str, target_dir: str) -> str:
+    safe_name = _trim_name(safe_name)
     i = 0
     o_name, o_ext = os.path.splitext(safe_name)
     while os.path.exists(os.path.join(target_dir, safe_name)):
         i += 1
         safe_name = f"{o_name} ({i}){o_ext}"
+        if len(safe_name) > MAX_FILE_NAME_LEN:
+            max_len = MAX_FILE_NAME_LEN - len(f" ({i}){o_ext}")
+            o_name = _trim_name(o_name, max_len)
+            safe_name = f"{o_name} ({i}){o_ext}"
+
     return safe_name
+
+
+def _trim_name(safe_name: str, max_len=MAX_FILE_NAME_LEN) -> str:
+    """ Trim file name to 255 characters while maintaining extension
+        255 characters is max file name length on linux and macOS
+        Windows has a path limit of 260 characters which includes
+        the entire path (drive letter, path, and file name)
+        This does not trim the path length, just the file name
+
+        max_len: if provided, trims to this length otherwise MAX_FILE_NAME_LEN
+
+        Raises: ValueError if the file name is too long and cannot be trimmed
+    """
+    if len(safe_name) <= max_len:
+        return safe_name
+
+    drop_chars = len(safe_name) - max_len
+    file_parts = safe_name.rsplit(".", 1)
+    if len(file_parts) != 2:
+        return f"{file_parts[0][:-drop_chars]}"
+    if len(file_parts[0]) > drop_chars:
+        return f"{file_parts[0][:-drop_chars]}.{file_parts[1]}"
+    else:
+        raise ValueError("File name is too long but cannot be safely trimmed: {safe_name}")  # noqa: E501

tests/test_note_exporter_util.py

@@ -1,5 +1,7 @@
 import os
 
+import pytest
+
 from evernote_backup import note_exporter_util
 from evernote_backup.note_exporter_util import (
     SafePath,
@@ -58,6 +60,64 @@ def test_get_safe_path():
     assert expected_result == result
 
 
+def test_safe_path_long_file_name(tmp_path):
+    """Test that SafePath trims a long file name with extension"""
+    test_dir = tmp_path / "test"
+    long_file_name = "X" * 255 + ".ext"
+    expected_file_name = "X" * 251 + ".ext"
+    expected_file = tmp_path / "test" / "test1" / expected_file_name
+
+    safe_path = SafePath(str(test_dir))
+    result_file_path = safe_path.get_file("test1", long_file_name)
+
+    expected_file.touch()
+
+    assert expected_file.is_file()
+    assert result_file_path == str(expected_file)
+
+
+def test_safe_path_long_file_name_no_ext(tmp_path):
+    """Test that SafePath trims a long file name with no extension"""
+    test_dir = tmp_path / "test"
+    long_file_name = "X" * 260
+    expected_file_name = "X" * 255
+    expected_file = tmp_path / "test" / "test1" / expected_file_name
+
+    safe_path = SafePath(str(test_dir))
+    result_file_path = safe_path.get_file("test1", long_file_name)
+
+    expected_file.touch()
+
+    assert expected_file.is_file()
+    assert result_file_path == str(expected_file)
+
+
+def test_safe_path_long_file_name_invalid(tmp_path):
+    """Test that SafePath raises ValueError if path is too long but cannot be trimmed"""
+    test_dir = tmp_path / "test"
+    bad_file_name = "X" + "." + "x" * 255
+
+    safe_path = SafePath(str(test_dir))
+    with pytest.raises(ValueError):
+        safe_path.get_file("test1", bad_file_name)
+
+
+def test_safe_path_no_trim(tmp_path):
+    """Test that the SafePath does not trim the path if the path is not too long"""
+    test_dir = tmp_path / "test"
+    max_file_name = "X" * 251 + ".ext"
+    expected_file_name = max_file_name
+    expected_file = tmp_path / "test" / "test1" / expected_file_name
+
+    safe_path = SafePath(str(test_dir))
+    result_file_path = safe_path.get_file("test1", max_file_name)
+
+    expected_file.touch()
+
+    assert expected_file.is_file()
+    assert result_file_path == str(expected_file)
+
+
 def test_get_non_existant_name_first(mocker):
     mock_file_check = mocker.patch("evernote_backup.note_exporter_util.os.path.exists")
     mock_file_check.return_value = False
@@ -80,6 +140,26 @@ def test_get_non_existant_name(mocker):
     assert expected_filename == result_filename
 
 
+def test_get_non_existant_name_trim(mocker):
+    """Test _get_non_existant_name() trims the file name if it is too long"""
+    initial_name = "X" * 255 + ".ext"
+    expected_filename = "X" * 251 + ".ext"
+    result_filename = _get_non_existant_name(initial_name, "fake_dir")
+
+    assert expected_filename == result_filename
+
+
+def test_get_non_existant_name_trim_bad_name(mocker):
+    """Test _get_non_existant_name() trims the file name if it is too long after incrementing"""
+    mock_file_check = mocker.patch("evernote_backup.note_exporter_util.os.path.exists")
+    mock_file_check.side_effect = [True, True, False]
+    initial_name = "X" * 251 + ".ext"
+    expected_filename = "X" * 247 + " (2).ext"
+    result_filename = _get_non_existant_name(initial_name, "fake_dir")
+
+    assert expected_filename == result_filename
+
+
 def test_replace_bad_characters():
     initial_name = r'test<>:"/\|?*'
     expected_filename = r"test_________"