cli: cleanup http error handling

Use more specific exception request exception handling to provide
better error messages.

Define an interal request function for get, post and delete to
reuse code.

cli/cli.py

@@ -46,53 +46,42 @@ def _log_http_status_code(res):
 
 class OgREST():
     def __init__(self, ip, port, api_token):
+        if not ip or not port or not api_token:
+            raise ValueError("IP, port, and API token must be provided.")
         self.URL = f'http://{ip}:{port}'
         self.HEADERS = {'Authorization': api_token}
 
-    def get(self, path, payload=None):
+    def _request(self, method, path, payload, expected_status):
         try:
-            res = requests.get(f'{self.URL}{path}',
-                             headers=self.HEADERS,
-                             json=payload)
-
-            if res.status_code != 200:
+            res = requests.request(
+                method,
+                f'{self.URL}{path}',
+                headers=self.HEADERS,
+                json=payload,
+            )
+            if res.status_code not in expected_status:
                 _log_http_status_code(res)
                 return None
+            return res
 
+        except requests.exceptions.ConnectionError:
+            print("Cannot connect to ogserver")
+        except requests.exceptions.Timeout:
+            print("Request to ogserver timed out")
+        except requests.exceptions.TooManyRedirects:
+            print("Too many redirects occurred while contacting ogserver")
         except requests.exceptions.RequestException as e:
-            print(f"Error: Cannot connect to ogServer: {e}")
-            return None
+            print(f"An error occurred while contacting ogserver: {e}")
+        return None
 
-        return res
+    def get(self, path, payload, payload=None):
+        return self._request('GET', path, payload, expected_status={200})
 
     def post(self, path, payload):
-        try:
-            res = requests.post(f'{self.URL}{path}',
-                              headers=self.HEADERS,
-                              json=payload)
-
-            if res.status_code not in {200, 202}:
-                _log_http_status_code(res)
-                return None
-
-        except requests.exceptions.RequestException as e:
-            print(f"Error: Cannot connect to ogServer: {e}")
-            return None
-
-        return res
+        return self._request('POST', path, payload, expected_status={200, 202})
 
     def delete(self, path, payload):
-        try:
-            res = requests.delete(f'{self.URL}{path}',
-                                headers=self.HEADERS,
-                                json=payload)
-            if res.status_code != 200:
-                _log_http_status_code(res)
-                return None
-        except IOError as e:
-            print(f"Error: Cannot connect to ogServer: {e}")
-            return None
-        return res
+        return self._request('DELETE', path, payload, expected_status={200})
 
 
 class OgCLI():