[Python-Client] Cannot list namespaces under the root namespace when using the dot delimiter

[mchades]

I set up a Lance REST server according to the Lance REST protocol, but I encountered an error when trying to list namespaces under the root using a Python client with a dot as the delimiter (but work well with $ delimiter).

Using the Java client did not encounter similar issues. I found that the Python client uses urllib3, which normalizes dots in the path, removing them from the path, thus causing a 404.

[fangyinc]

I fixed this issue in PR #247.

[mchades]

Thanks for your response!

I saw your PR fixing the escape issue in ObjectIdentifier, but the issue I encountered is on the Python client side — they are not the same.

[fangyinc]

Sorry, this is indeed a separate issue. I've reviewed the relevant source code

The issue you're encountering is caused by Servlet path normalization. When you request http://localhost:8080/v1/namespace/./list?delimiter=., the /. portion is automatically normalized (removed) by the servlet container before it reaches the Spring controller, resulting in the actual path being /v1/namespace/list.

This is standard behavior according to the HTTP and Servlet specifications, where:

• . represents the current directory and is removed during path normalization
• .. represents the parent directory and is similarly processed

This normalization happens at the servlet container level for security and consistency reasons, and it occurs before Spring's routing logic can process the request.

Hope this helps!

[mchades]

yes, The dot delimiter is commonly used in namespaces, and we should handle it properly in the Python client (It works well with the Java client).

[fangyinc]

yes, The dot delimiter is commonly used in namespaces, and we should handle it properly in the Python client (It works well with the Java client).

I tried to fix this issue in #251.

Python usage:

from lance_namespace import connect, ListNamespacesRequest
conf = {
    "uri": "http://localhost:9101/lance", 
    "delimiter": ".", 
    "root": "/tmp/warehouse", 
}
ns = connect("rest", conf)

list_namespaces_request = ListNamespacesRequest()
list_namespaces_request.id = []
print(ns.list_namespaces(list_namespaces_request))