Use duck typing and make error messages consistent

Also, add a missing return when getting packed attribute fails in
extension.

Author: oschwald

extension/maxminddb.c

@@ -185,11 +185,13 @@ static int ip_converter(PyObject *obj, struct sockaddr_storage *ip_address)
         Py_ssize_t len = strlen(ipstr);
 #endif
         if (!ipstr) {
-            PyErr_SetString(PyExc_ValueError, "invalid string");
+            PyErr_SetString(PyExc_TypeError,
+                            "argument 1 contains an invalid string");
             return 0;
         }
         if (strlen(ipstr) != (size_t)len) {
-            PyErr_SetString(PyExc_ValueError, "embedded null character");
+            PyErr_SetString(PyExc_TypeError,
+                            "argument 1 contains an embedded null character");
             return 0;
         }
 
@@ -214,13 +216,16 @@ static int ip_converter(PyObject *obj, struct sockaddr_storage *ip_address)
     }
     PyObject *packed = PyObject_GetAttrString(obj, "packed");
     if (!packed) {
-        PyErr_SetString(PyExc_ValueError, "error about object type");
+        PyErr_SetString(PyExc_TypeError,
+                        "argument 1 must be a string or ipaddress object");
+        return 0;
     }
     Py_ssize_t len;
     char *bytes;
     int status = PyBytes_AsStringAndSize(packed, &bytes, &len);
     if (status == -1) {
-        PyErr_SetString(PyExc_ValueError, "cannot get bytes");
+        PyErr_SetString(PyExc_TypeError,
+                        "argument 1 must be a string or ipaddress object");
         Py_DECREF(packed);
         return 0;
     }
@@ -241,7 +246,8 @@ static int ip_converter(PyObject *obj, struct sockaddr_storage *ip_address)
             return 1;
         }
     default:
-        PyErr_SetString(PyExc_ValueError, "unexpected packed length");
+        PyErr_SetString(PyExc_ValueError,
+                        "argument 1 returned an unexpected packed length for address");
         Py_DECREF(packed);
         return 0;
     }

maxminddb/reader.py

@@ -104,26 +104,25 @@ def get(self, ip_address):
         Arguments:
         ip_address -- an IP address in the standard string notation
         """
-        if isinstance(ip_address,
-                      (ipaddress.IPv4Address, ipaddress.IPv6Address)):
-            address = ip_address
-        elif isinstance(ip_address, string_type):
+        if isinstance(ip_address, string_type):
             address = compat_ip_address(ip_address)
         else:
-            raise TypeError('argument 1 must be %s, not %s' %
-                            (string_type_name, type(ip_address).__name__))
+            address = ip_address
+
+        try:
+            packed_address = bytearray(address.packed)
+        except AttributeError:
+            raise TypeError('argument 1 must be a string or ipaddress object')
 
         if address.version == 6 and self._metadata.ip_version == 4:
             raise ValueError(
                 'Error looking up {0}. You attempted to look up '
                 'an IPv6 address in an IPv4-only database.'.format(ip_address))
-        pointer = self._find_address_in_tree(address)
+        pointer = self._find_address_in_tree(packed_address)
 
         return self._resolve_data_pointer(pointer) if pointer else None
 
-    def _find_address_in_tree(self, ip_address):
-        packed = bytearray(ip_address.packed)
-
+    def _find_address_in_tree(self, packed):
         bit_count = len(packed) * 8
         node = self._start_node(bit_count)
 

tests/reader_test.py

@@ -193,6 +193,14 @@ def test_no_get_args(self):
             reader.get()
         reader.close()
 
+    def test_incorrect_get_arg_type(self):
+        reader = open_database('tests/data/test-data/GeoIP2-City-Test.mmdb',
+                               self.mode)
+        with self.assertRaisesRegex(
+                TypeError, "argument 1 must be a string or ipaddress object"):
+            reader.get(1)
+        reader.close()
+
     def test_metadata_args(self):
         reader = open_database(
             'tests/data/test-data/MaxMind-DB-test-decoder.mmdb', self.mode)