Proposed code to fix issue #2198 finding the spatialite dll in Windows

datasette/utils/__init__.py

@@ -873,6 +873,15 @@ class LoadExtension(click.ParamType):
     name = "path:entrypoint?"
 
     def convert(self, value, param, ctx):
+        #:\ indicates we're on a Windows machine study the argument a bit more
+        if ":\\" in r"%r" % value:
+            path_entry = value.split(":", 2)
+            if len(path_entry) < 3:
+                return value
+            # argument contains a Windows/DOS path and an entry point
+            path = path_entry[0] + ":" + path_entry[1]
+            entrypoint = path_entry[-1]
+            return path, entrypoint
         if ":" not in value:
             return value
         path, entrypoint = value.split(":", 1)

docs/spatialite.rst

@@ -70,6 +70,11 @@ Depending on your distribution, you should be able to run Datasette something li
 
 If you are unsure of the location of the module, try running ``locate mod_spatialite`` and see what comes back.
 
+Installing SpatiaLite on Windows
+-----------------------------
+
+For Windows, you may find binaries on the `Gaia-SINS <https://www.gaia-gis.it/gaia-sins/>`_ home page.
+
 Spatial indexing latitude/longitude columns
 ===========================================
 

tests/test_loadextension.py

@@ -0,0 +1,31 @@
+from datasette.utils import LoadExtension
+
+
+def test_dos_path():
+    path_string = "C:\Windows\System32\mod_spatialite.dll"
+    le = LoadExtension()
+    path = le.convert(path_string, None, None)
+    assert path == "C:\Windows\System32\mod_spatialite.dll"
+
+
+def test_dos_pathentry():
+    path_entry = "C:\Windows\System32\mod_spatialite.dll:testentry"
+    le = LoadExtension()
+    pathen, entry = le.convert(path_entry, None, None)
+    assert pathen == "C:\Windows\System32\mod_spatialite.dll"
+    assert entry == "testentry"
+
+
+def test_linux_path():
+    path_string = "/base/test/test2"
+    le = LoadExtension()
+    path = le.convert(path_string, None, None)
+    assert path == path_string
+
+
+def test_linux_path_entry():
+    path_string = "/base/test/test2:testentry"
+    le = LoadExtension()
+    path, entry = le.convert(path_string, None, None)
+    assert path == "/base/test/test2"
+    assert entry == "testentry"