Merge pull request #97 from lsst/tickets/DM-46701

DM-46701: Implement generate_presigned_get_url for plain HTTP

Author: dhirving

python/lsst/resources/http.py

@@ -1261,7 +1261,9 @@ def generate_presigned_get_url(self, *, expiration_time_seconds: int) -> str:
             HTTP URL signed for GET.
         """
         if not self.is_webdav_endpoint:
-            return super().generate_presigned_get_url(expiration_time_seconds=expiration_time_seconds)
+            # This is already an HTTP URL readable without any authentication
+            # credentials, so return it as-is.
+            return str(self)
 
         return self._sign_with_macaroon(ActivityCaveat.DOWNLOAD, expiration_time_seconds)
 
@@ -1867,7 +1869,7 @@ def _openImpl(
             if mode == "r":
                 # cast because the protocol is compatible, but does not have
                 # BytesIO in the inheritance tree
-                yield io.TextIOWrapper(cast(io.BytesIO, handle), encoding=encoding)
+                yield io.TextIOWrapper(cast(Any, handle), encoding=encoding)
             else:
                 yield handle
         else:

tests/test_http.py

@@ -460,6 +460,25 @@ def test_is_webdav_endpoint(self):
         responses.add(responses.OPTIONS, notWebdavEndpoint, status=403)
         self.assertFalse(ResourcePath(notWebdavEndpoint).is_webdav_endpoint)
 
+    @responses.activate
+    def test_plain_http_url_signing(self):
+        # As in test_is_webdav_endpoint above, configure a URL to appear as a
+        # non-webdav HTTP server.
+        plainHttpEndpoint = "http://nonwebdav.test"
+        responses.add(responses.OPTIONS, plainHttpEndpoint, status=200)
+
+        # Plain HTTP URLs are already readable without authentication, so
+        # generating a pre-signed URL is a no-op.
+        path = ResourcePath("http://nonwebdav.test/file")
+        self.assertEqual(
+            path.generate_presigned_get_url(expiration_time_seconds=300), "http://nonwebdav.test/file"
+        )
+
+        # Writing to an arbitrary plain HTTP URL is unlikely to work, so we
+        # don't generate put URLs.
+        with self.assertRaises(NotImplementedError):
+            path.generate_presigned_put_url(expiration_time_seconds=300)
+
     @responses.activate
     def test_server_identity(self):
         server = "MyServer/v1.2.3"