Add method to determine server TLD (#8)

copied from Hochfrequenz/tmdsclient.py#22

Author: hf-kklein

src/bssclient/client/bssclient.py

@@ -7,6 +7,7 @@
 
 from aiohttp import BasicAuth, ClientSession, ClientTimeout
 from more_itertools import chunked
+from yarl import URL
 
 from bssclient.client.config import BssConfig
 from bssclient.models.aufgabe import AufgabeStats
@@ -27,6 +28,25 @@ def __init__(self, config: BssConfig):
         self._session: Optional[ClientSession] = None
         _logger.info("Instantiated BssClient with server_url %s", str(self._config.server_url))
 
+    def get_top_level_domain(self) -> URL | None:
+        """
+        Returns the top level domain of the server_url; this is useful to differentiate prod from test systems.
+        If the server_url is an IP address, None is returned.
+        """
+        # this method is unit tested; check the testcases to understand its branches
+        domain_parts = self._config.server_url.host.split(".")  # type:ignore[union-attr]
+        if all(x.isnumeric() for x in domain_parts):
+            # seems like this is an IP address
+            return None
+        if not any(domain_parts):
+            return self._config.server_url
+        tld: str
+        if domain_parts[-1] == "localhost":
+            tld = ".".join(domain_parts[-1:])
+        else:
+            tld = ".".join(domain_parts[-2:])
+        return URL(self._config.server_url.scheme + "://" + tld)
+
     async def _get_session(self) -> ClientSession:
         """
         returns a client session (that may be reused or newly created)

unittests/test_bss_client.py

@@ -0,0 +1,23 @@
+import pytest
+from yarl import URL
+
+from bssclient import BssClient, BssConfig
+
+
+@pytest.mark.parametrize(
+    "actual_url,expected_tld",
+    [
+        pytest.param(URL("https://bss.example.com"), URL("https://example.com")),
+        pytest.param(URL("https://bss.prod.de"), URL("https://prod.de")),
+        pytest.param(URL("https://test.de"), URL("https://test.de")),
+        pytest.param(URL("https://localhost"), URL("https://localhost")),
+        pytest.param(URL("http://test.localhost"), URL("http://localhost")),
+        pytest.param(URL("http://foo.bar.test.localhost"), URL("http://localhost")),
+        pytest.param(URL("http://1.2.3.4"), None),
+    ],
+)
+def test_get_tld(actual_url: URL, expected_tld: URL):
+    config = BssConfig(server_url=actual_url, usr="user", pwd="password")
+    client = BssClient(config)
+    actual = client.get_top_level_domain()
+    assert actual == expected_tld