better validation

radixtarget/helpers.py

@@ -1,3 +1,4 @@
+import re
 import ipaddress
 
 
@@ -28,6 +29,26 @@ def is_ip(host):
     return ipaddress._IPAddressBase in host.__class__.__mro__
 
 
+dns_name_regex = re.compile(r"^[\w]+[\w.-]*$", re.I)
+
+
+def is_dns_name(host):
+    """
+    Check if the given host is a valid DNS name.
+
+    This function uses a regular expression to determine if the provided
+    host string matches the pattern of a valid DNS name. The pattern allows
+    alphanumeric characters, underscores, hyphens, and periods, and is case-insensitive.
+
+    Args:
+        host (str): The host string to check.
+
+    Returns:
+        bool: True if the host is a valid DNS name, False otherwise.
+    """
+    return bool(dns_name_regex.match(host))
+
+
 def make_ip(host):
     """Convert a host to an IP network or return it as a lowercase string.
 

radixtarget/radixtarget.py

@@ -3,7 +3,7 @@
 
 from radixtarget.tree.ip import IPRadixTree
 from radixtarget.tree.dns import DNSRadixTree
-from radixtarget.helpers import is_ip, make_ip, host_size_key
+from radixtarget.helpers import is_ip, is_dns_name, make_ip, host_size_key
 
 
 sentinel = object()
@@ -66,8 +66,10 @@ def get(self, host, raise_error=False):
         host = make_ip(host)
         if is_ip(host):
             return self.ip_tree.search(host, raise_error=raise_error)
-        else:
+        elif is_dns_name(host):
             return self.dns_tree.search(host, raise_error=raise_error)
+        else:
+            raise ValueError(f"Invalid host: '{host}'")
 
     def search(self, host, raise_error=False):
         """
@@ -128,8 +130,10 @@ def _add_host(self, host, data=None):
         self._hosts.add(host)
         if is_ip(host):
             return self.ip_tree.insert(host, data=data)
-        else:
+        elif is_dns_name(host):
             return self.dns_tree.insert(host, data=data)
+        else:
+            raise ValueError(f"Invalid host: '{host}'")
 
     @property
     def hosts(self):

radixtarget/test/test_radixtarget.py

@@ -349,3 +349,14 @@ def test_radixtarget():
         assert "www.evilcorp.co.uk" in target
         assert not "api.evilcorp.co.uk" in target
         assert not "api.www.evilcorp.co.uk" in target
+
+        # test with invalid inputs
+        with pytest.raises(ValueError, match=".*Invalid host: 'http://example.com'.*"):
+            target = RadixTarget("http://example.com")
+        target = RadixTarget("example.com")
+        with pytest.raises(ValueError, match=".*Invalid host: 'evilcorp.com:80'.*"):
+            target.get("evilcorp.com:80")
+        with pytest.raises(ValueError, match=".*Invalid host: 'www.evilcorp.com:80'.*"):
+            target.add("www.evilcorp.com:80")
+        with pytest.raises(ValueError, match=".*Invalid host: 'evilcorp.com:80'.*"):
+            "evilcorp.com:80" in target