fix: mo.notebook_location() with incorrect :// (#3393)

When converting to `Path()`, `://` gets normalized to `:/`, so this adds
it back if it was removed

marimo/_runtime/runtime.py

@@ -317,8 +317,17 @@ def notebook_dir() -> pathlib.Path | None:
     return None
 
 
+class URLPath(pathlib.PurePosixPath):
+    """
+    Wrapper around pathlib.Path that preserves the "://" in the URL protocol.
+    """
+
+    def __str__(self) -> str:
+        return super().__str__().replace(":/", "://")
+
+
 @mddoc
-def notebook_location() -> pathlib.Path | None:
+def notebook_location() -> pathlib.PurePath | None:
     """Get the location of the currently executing notebook.
 
     In WASM, this is the URL of webpage, for example, `https://my-site.com`.
@@ -342,7 +351,7 @@ def notebook_location() -> pathlib.Path | None:
         ```
 
     Returns:
-        pathlib.Path | None: A pathlib.Path object representing the URL or directory of the current
+        Path | None: A Path object representing the URL or directory of the current
             notebook, or None if the notebook's directory cannot be determined.
     """
     if is_pyodide():
@@ -352,11 +361,14 @@ def notebook_location() -> pathlib.Path | None:
         # The location looks like https://marimo-team.github.io/marimo-gh-pages-template/notebooks/assets/worker-BxJ8HeOy.js
         # We want to crawl out of the assets/ folder
         if "assets" in path_location.parts:
-            return path_location.parent.parent
-        return path_location
+            return URLPath(str(path_location.parent.parent))
+        return URLPath(str(path_location))
 
     else:
-        return notebook_dir()
+        nb_dir = notebook_dir()
+        if nb_dir is not None:
+            return nb_dir
+        return None
 
 
 @dataclasses.dataclass

tests/_runtime/test_runtime.py

@@ -4,7 +4,6 @@
 import sys
 import textwrap
 from dataclasses import dataclass
-from pathlib import Path
 from typing import TYPE_CHECKING, Sequence
 
 import pytest
@@ -1039,6 +1038,9 @@ async def test_notebook_location(
         assert "dir" in k.globals
         assert k.globals["dir"] is k.globals["loc"]
 
+    @pytest.mark.skipif(
+        sys.platform == "win32", reason="Windows paths behave differently"
+    )
     async def test_notebook_location_for_pyodide(
         self, any_kernel: Kernel, exec_req: ExecReqProvider
     ) -> None:
@@ -1060,8 +1062,13 @@ async def test_notebook_location_for_pyodide(
                     )
                 ]
             )
-            assert k.globals["loc"] == Path(
-                "https://marimo-team.github.io/marimo-gh-pages-template/notebooks"
+            assert (
+                str(k.globals["loc"])
+                == "https://marimo-team.github.io/marimo-gh-pages-template/notebooks"
+            )
+            assert (
+                str(k.globals["loc"] / "public" / "data.csv")
+                == "https://marimo-team.github.io/marimo-gh-pages-template/notebooks/public/data.csv"
             )
         finally:
             del sys.modules["pyodide"]