Return file:////server/share URIs for UNC paths on Windows

upath/implementations/local.py

@@ -758,6 +758,16 @@ class PosixUPath(LocalPath, pathlib.PosixPath, UPath):  # type: ignore[misc]
     class WindowsUPath(LocalPath, pathlib.WindowsPath):
         __slots__ = ()
 
+        def as_uri(self) -> str:
+            uri = super().as_uri()
+            # pathlib writes UNC paths as file://server/share/..., but fsspec
+            # reads the part after file:// as a path, so that URI would point
+            # at a local server/share/... directory. Keep the server in the
+            # path instead: file:////server/share/...
+            if uri.startswith("file://") and not uri.startswith("file:///"):
+                uri = "file:////" + uri[len("file://") :]
+            return uri
+
         if os.name != "nt":
 
             def __new__(

upath/tests/pathlib/test_pathlib_310.py

@@ -1231,6 +1231,25 @@ class PosixPathAsPureTest(PurePosixPathTest, unittest.TestCase):
 class WindowsPathAsPureTest(PureWindowsPathTest, unittest.TestCase):
     cls = WindowsUPath
 
+    def test_as_uri(self):
+        # UPath keeps the server of a UNC path in the URI path
+        # (file:////server/share) where pathlib uses file://server/share,
+        # because fsspec reads file://server/share as a relative path
+        P = self.cls
+        with self.assertRaises(ValueError):
+            P('/a/b').as_uri()
+        with self.assertRaises(ValueError):
+            P('c:a/b').as_uri()
+        self.assertEqual(P('c:/').as_uri(), 'file:///c:/')
+        self.assertEqual(P('c:/a/b.c').as_uri(), 'file:///c:/a/b.c')
+        self.assertEqual(P('c:/a/b%#c').as_uri(), 'file:///c:/a/b%25%23c')
+        self.assertEqual(P('c:/a/b\xe9').as_uri(), 'file:///c:/a/b%C3%A9')
+        self.assertEqual(P('//some/share/').as_uri(), 'file:////some/share/')
+        self.assertEqual(P('//some/share/a/b.c').as_uri(),
+                         'file:////some/share/a/b.c')
+        self.assertEqual(P('//some/share/a/b%#c\xe9').as_uri(),
+                         'file:////some/share/a/b%25%23c%C3%A9')
+
     def test_owner(self):
         P = self.cls
         with self.assertRaises(NotImplementedError):

upath/tests/pathlib/test_pathlib_311.py

@@ -1233,6 +1233,25 @@ class PosixPathAsPureTest(PurePosixPathTest, unittest.TestCase):
 class WindowsPathAsPureTest(PureWindowsPathTest, unittest.TestCase):
     cls = WindowsUPath
 
+    def test_as_uri(self):
+        # UPath keeps the server of a UNC path in the URI path
+        # (file:////server/share) where pathlib uses file://server/share,
+        # because fsspec reads file://server/share as a relative path
+        P = self.cls
+        with self.assertRaises(ValueError):
+            P('/a/b').as_uri()
+        with self.assertRaises(ValueError):
+            P('c:a/b').as_uri()
+        self.assertEqual(P('c:/').as_uri(), 'file:///c:/')
+        self.assertEqual(P('c:/a/b.c').as_uri(), 'file:///c:/a/b.c')
+        self.assertEqual(P('c:/a/b%#c').as_uri(), 'file:///c:/a/b%25%23c')
+        self.assertEqual(P('c:/a/b\xe9').as_uri(), 'file:///c:/a/b%C3%A9')
+        self.assertEqual(P('//some/share/').as_uri(), 'file:////some/share/')
+        self.assertEqual(P('//some/share/a/b.c').as_uri(),
+                         'file:////some/share/a/b.c')
+        self.assertEqual(P('//some/share/a/b%#c\xe9').as_uri(),
+                         'file:////some/share/a/b%25%23c%C3%A9')
+
     def test_owner(self):
         P = self.cls
         with self.assertRaises(NotImplementedError):

upath/tests/pathlib/test_pathlib_312.py

@@ -1541,6 +1541,25 @@ class PosixPathAsPureTest(PurePosixPathTest, unittest.TestCase):
 class WindowsPathAsPureTest(PureWindowsPathTest, unittest.TestCase):
     cls = WindowsUPath
 
+    def test_as_uri(self):
+        # UPath keeps the server of a UNC path in the URI path
+        # (file:////server/share) where pathlib uses file://server/share,
+        # because fsspec reads file://server/share as a relative path
+        P = self.cls
+        with self.assertRaises(ValueError):
+            P('/a/b').as_uri()
+        with self.assertRaises(ValueError):
+            P('c:a/b').as_uri()
+        self.assertEqual(P('c:/').as_uri(), 'file:///c:/')
+        self.assertEqual(P('c:/a/b.c').as_uri(), 'file:///c:/a/b.c')
+        self.assertEqual(P('c:/a/b%#c').as_uri(), 'file:///c:/a/b%25%23c')
+        self.assertEqual(P('c:/a/b\xe9').as_uri(), 'file:///c:/a/b%C3%A9')
+        self.assertEqual(P('//some/share/').as_uri(), 'file:////some/share/')
+        self.assertEqual(P('//some/share/a/b.c').as_uri(),
+                         'file:////some/share/a/b.c')
+        self.assertEqual(P('//some/share/a/b%#c\xe9').as_uri(),
+                         'file:////some/share/a/b%25%23c%C3%A9')
+
     def test_owner(self):
         P = self.cls
         with self.assertRaises(NotImplementedError):

upath/tests/pathlib/test_pathlib_39.py

@@ -1192,6 +1192,25 @@ class PosixPathAsPureTest(PurePosixPathTest, unittest.TestCase):
 class WindowsPathAsPureTest(PureWindowsPathTest, unittest.TestCase):
     cls = WindowsUPath
 
+    def test_as_uri(self):
+        # UPath keeps the server of a UNC path in the URI path
+        # (file:////server/share) where pathlib uses file://server/share,
+        # because fsspec reads file://server/share as a relative path
+        P = self.cls
+        with self.assertRaises(ValueError):
+            P('/a/b').as_uri()
+        with self.assertRaises(ValueError):
+            P('c:a/b').as_uri()
+        self.assertEqual(P('c:/').as_uri(), 'file:///c:/')
+        self.assertEqual(P('c:/a/b.c').as_uri(), 'file:///c:/a/b.c')
+        self.assertEqual(P('c:/a/b%#c').as_uri(), 'file:///c:/a/b%25%23c')
+        self.assertEqual(P('c:/a/b\xe9').as_uri(), 'file:///c:/a/b%C3%A9')
+        self.assertEqual(P('//some/share/').as_uri(), 'file:////some/share/')
+        self.assertEqual(P('//some/share/a/b.c').as_uri(),
+                         'file:////some/share/a/b.c')
+        self.assertEqual(P('//some/share/a/b%#c\xe9').as_uri(),
+                         'file:////some/share/a/b%25%23c%C3%A9')
+
     def test_owner(self):
         P = self.cls
         with self.assertRaises(NotImplementedError):

upath/tests/test_core.py

@@ -33,6 +33,15 @@ def test_windows_path(local_testdir):
     assert isinstance(UPath(local_testdir), pathlib.WindowsPath)
 
 
+@only_on_windows
+def test_windows_unc_path_as_uri_round_trip():
+    # https://github.com/fsspec/universal_pathlib/issues/557
+    pth = UPath(r"\\server\share\file")
+    uri = pth.as_uri()
+    assert uri == "file:////server/share/file"
+    assert UPath(uri).path == "//server/share/file"
+
+
 def test_UPath_untested_protocol_warning(clear_registry):
     with warnings.catch_warnings(record=True) as w:
         _ = UPath("mock:/")