updated get_base_url impl

tap_zendesk_chat/http.py

@@ -9,21 +9,44 @@
 class RateLimitException(Exception):
     pass
 
+class InvalidConfigurationError(Exception):
+    pass
+
 
 class Client:
     def __init__(self, config):
         self.access_token = config["access_token"]
         self.user_agent = config.get("user_agent", "tap-zendesk-chat")
         self.headers = {}
+        self.subdomain = config.get("subdomain")
         self.headers["Authorization"] = f"Bearer {self.access_token}"
         self.headers["User-Agent"] = self.user_agent
-        if "subdomain" in config:
-            self.base_url = f"https://{config['subdomain']}.zendesk.com"
-        else:
-            self.base_url =  BASE_URL
-            LOGGER.warning("Missing Subdomain, please recheck the configuration")
+        self.base_url = self.get_base_url()
         self.session = requests.Session()
 
+    def get_base_url(self):
+        """
+        Determines the base URL to use for Zendesk API requests.
+
+        Checks the availability of zendesk chat endpoints
+        and returns the available one
+        Returns:
+            str: The base URL to use for subsequent API requests.
+
+        Raises:
+            InvalidConfigurationError: If neither endpoint is accessible.
+        """
+        urls = [
+            (f"https://{self.subdomain}.zendesk.com" , "/api/v2/chat/agents"),
+            (BASE_URL , "/api/v2/agents")
+        ]
+        for domain, endpoint in urls:
+            resp = requests.get(f"{domain}{endpoint}", headers=self.headers)
+            LOGGER.info("API CHECK %s %s", resp.url, resp.status_code)
+            if resp.status_code == 200:
+                return domain
+        raise InvalidConfigurationError("Please check the URL or reauthenticate")
+
     @backoff.on_exception(backoff.expo, RateLimitException, max_tries=10, factor=2)
     def request(self, tap_stream_id, params=None, url=None, url_extra=""):
         with metrics.http_request_timer(tap_stream_id) as timer: