TextDB can walk up directory trees

src/dbetto/textdb.py

@@ -17,6 +17,7 @@
 
 import json
 import logging
+import os
 import re
 import sys
 from collections.abc import Iterator
@@ -68,7 +69,11 @@ class TextDB:
     """
 
     def __init__(
-        self, path: str | Path, lazy: str | bool = False, hidden: bool = False
+        self,
+        path: str | Path,
+        lazy: str | bool = False,
+        hidden: bool = False,
+        allow_up_tree=False,
     ) -> None:
         """Construct a :class:`.TextDB` object.
 
@@ -82,6 +87,8 @@ def __init__(
             session.
         hidden
             ignore hidden (i.e. starting with ".") files of directories.
+        allow_up_tree
+            allow paths that go up the tree (i.e. contain "..").
         """
         if isinstance(lazy, bool):
             self.__lazy__ = lazy
@@ -92,6 +99,7 @@ def __init__(
             raise ValueError(msg)
 
         self.__hidden__ = hidden
+        self.__allow_up_tree__ = allow_up_tree
         self.__path__ = Path(path).expanduser().resolve()
 
         if not self.__path__.is_dir():
@@ -270,16 +278,39 @@ def group(self, label: str) -> AttrsDict:
     def __getitem__(self, item: str | Path) -> TextDB | AttrsDict | list | None:
         """Access files or directories in the database."""
         # resolve relative paths / links, but keep it relative to self.__path__
+        # up the tree ("..") outside self.__path__ is only allowed if
+        # self.__allow_up_tree__ is True
         item = Path(item)
 
         if item.is_absolute() and item.is_relative_to(self.__path__):
-            item = item.expanduser().resolve().relative_to(self.__path__)
+            try:
+                item = item.expanduser().resolve().relative_to(self.__path__)
+            except ValueError:
+                if self.__allow_up_tree__:
+                    # Path.relative_to(walkup=True) only in python 3.12+
+                    item = Path(os.path.relpath(item, self.__path__))
+                else:
+                    raise
         elif not item.is_absolute():
-            item = (
-                (self.__path__ / item).expanduser().resolve().relative_to(self.__path__)
-            )
+            try:
+                item = (
+                    (self.__path__ / item)
+                    .expanduser()
+                    .resolve()
+                    .relative_to(self.__path__)
+                )
+            except ValueError:
+                if self.__allow_up_tree__:
+                    # Path.relative_to(walkup=True) only in python 3.12+
+                    item = Path(
+                        os.path.relpath(
+                            (self.__path__ / item).expanduser().resolve(), self.__path__
+                        )
+                    )
+                else:
+                    raise
         else:
-            msg = f"{item} lies outside the database root path {self.__path__!s}"
+            msg = f"{item} is not relative to the database root path {self.__path__!s}"
             raise ValueError(msg)
 
         ext_list = "[" + "|".join(self.__extensions__) + "]"
@@ -302,12 +333,21 @@ def __getitem__(self, item: str | Path) -> TextDB | AttrsDict | list | None:
             obj = db_ptr.__path__ / item.name
 
             # do not consider hidden files
-            if not self.__hidden__ and obj.name.startswith("."):
+            if not self.__hidden__ and (
+                obj.name.startswith(".") and not obj.name.startswith("..")
+            ):
+                msg = f"skipping hidden file: {obj}"
+                log.debug(msg)
                 return None
 
             # if directory, construct another TextDB object
             if obj.is_dir():
-                db_ptr.__store__[item_id] = TextDB(obj, lazy=self.__lazy__)
+                db_ptr.__store__[item_id] = TextDB(
+                    obj,
+                    lazy=self.__lazy__,
+                    hidden=self.__hidden__,
+                    allow_up_tree=self.__allow_up_tree__,
+                )
 
             else:
                 # try to attach an extension if file cannot be found

tests/test_textdb.py

@@ -132,6 +132,7 @@ def test_scan():
     jdb.scan(recursive=True)
 
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",
@@ -149,6 +150,7 @@ def test_scan():
     jdb.scan(recursive=False)
 
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",
@@ -164,6 +166,7 @@ def test_scan():
     jdb.scan(recursive=False, subdir="dir1")
 
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",
@@ -292,6 +295,7 @@ def test_lazyness():
     jdb = TextDB(testdb, lazy="auto")
     assert jdb.__lazy__ is True
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",
@@ -302,6 +306,7 @@ def test_lazyness():
     jdb = TextDB(testdb, lazy=True)
     assert jdb.__lazy__ is True
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",
@@ -312,6 +317,7 @@ def test_lazyness():
     jdb = TextDB(testdb, lazy=False)
     assert jdb.__lazy__ is False
     assert sorted(jdb.__dict__.keys()) == [
+        "__allow_up_tree__",
         "__ftypes__",
         "__hidden__",
         "__lazy__",