python-validators · yozachar · Mar 12, 2023 · Mar 11, 2023
diff --git a/docs/index.md b/docs/index.md
@@ -12,6 +12,8 @@
 
 ::: validators.hashes
 
+::: validators.hostname
+
 ::: validators.iban
 
 ::: validators.ip_address

diff --git a/tests/test_hostname.py b/tests/test_hostname.py
@@ -0,0 +1,68 @@
+"""Test Hostname."""
+# -*- coding: utf-8 -*-
+
+# external
+import pytest
+
+# local
+from validators import hostname, ValidationFailure
+
+
+@pytest.mark.parametrize(
+    ("value", "rfc_1034", "rfc_2782"),
+    [
+        # simple hostname w/ optional ports
+        ("ubuntu-pc:443", False, False),
+        ("this-pc", False, False),
+        ("lab-01a-notebook:404", False, False),
+        ("4-oh-4", False, False),
+        # hostname w/ optional ports
+        ("example.com:4444", False, False),
+        ("kräuter.com.", True, False),
+        ("xn----gtbspbbmkef.xn--p1ai:65535", False, False),
+        ("_example.com", False, True),
+        # ipv4 addr w/ optional ports
+        ("123.123.123.123:9090", False, False),
+        ("127.0.0.1:43512", False, False),
+        ("123.5.77.88:31000", False, False),
+        ("12.12.12.12:5353", False, False),
+        # ipv6 addr w/ optional ports
+        ("[::1]:22", False, False),
+        ("[dead:beef:0:0:0:0000:42:1]:5731", False, False),
+        ("[0:0:0:0:0:ffff:1.2.3.4]:80", False, False),
+        ("[0:a:b:c:d:e:f::]:53", False, False),
+    ],
+)
+def test_returns_true_on_valid_hostname(value: str, rfc_1034: bool, rfc_2782: bool):
+    """Test returns true on valid hostname."""
+    assert hostname(value, rfc_1034=rfc_1034, rfc_2782=rfc_2782)
+
+
+@pytest.mark.parametrize(
+    ("value", "rfc_1034", "rfc_2782"),
+    [
+        # bad (simple hostname w/ optional ports)
+        ("ubuntu-pc:443080", False, False),
+        ("this-pc-is-sh*t", False, False),
+        ("lab-01a-note._com_.com:404", False, False),
+        ("4-oh-4:@.com", False, False),
+        # bad (hostname w/ optional ports)
+        ("example.com:-4444", False, False),
+        ("xn----gtbspbbmkef.xn--p1ai:65538", False, False),
+        ("_example.com:0", False, True),
+        ("kräuter.com.:81_00", True, False),
+        # bad (ipv4 addr w/ optional ports)
+        ("123.123.123.123:99999", False, False),
+        ("127.0.0.1:", False, False),
+        ("123.5.-12.88:8080", False, False),
+        ("12.12.12.12:$#", False, False),
+        # bad (ipv6 addr w/ optional ports)
+        ("[::1]:[22]", False, False),
+        ("[dead:beef:0:-:0:-:42:1]:5731", False, False),
+        ("[0:0:0:0:0:ffff:1.2.3.4]:-65538", False, False),
+        ("[0:&:b:c:@:e:f:::9999", False, False),
+    ],
+)
+def test_returns_failed_validation_on_invalid_hostname(value: str, rfc_1034: bool, rfc_2782: bool):
+    """Test returns failed validation on invalid hostname."""
+    assert isinstance(hostname(value, rfc_1034=rfc_1034, rfc_2782=rfc_2782), ValidationFailure)
diff --git a/validators/__init__.py b/validators/__init__.py
@@ -7,6 +7,7 @@
 from .domain import domain
 from .email import email
 from .hashes import md5, sha1, sha224, sha256, sha512
+from .hostname import hostname
 from .i18n import fi_business_id, fi_ssn
 from .iban import iban
 from .ip_address import ipv4, ipv6
@@ -28,6 +29,7 @@
     "email",
     "fi_business_id",
     "fi_ssn",
+    "hostname",
     "iban",
     "ipv4",
     "ipv6",

diff --git a/validators/hostname.py b/validators/hostname.py
@@ -0,0 +1,107 @@
+"""Hostname."""
+# -*- coding: utf-8 -*-
+
+# standard
+from functools import lru_cache
+import re
+
+# local
+from .ip_address import ipv4, ipv6
+from .utils import validator
+from .domain import domain
+
+
+@lru_cache
+def _port_regex():
+    """Port validation regex."""
+    return re.compile(
+        r"^\:(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|"
+        + r"6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3})$",
+    )
+
+
+@lru_cache
+def _simple_hostname_regex():
+    """Simple hostname validation regex."""
+    return re.compile(r"^[a-zA-Z0-9][a-zA-Z0-9-]{0,61}[a-zA-Z0-9]$")
+
+
+@validator
+def hostname(
+    value: str,
+    /,
+    *,
+    may_have_port: bool = True,
+    skip_ip_addr: bool = False,
+    maybe_simple: bool = True,
+    rfc_1034: bool = False,
+    rfc_2782: bool = False,
+):
+    """Return whether or not given value is a valid hostname.
+
+    Examples:
+        >>> hostname("ubuntu-pc:443")
+        # Output: True
+        >>> hostname("this-pc")
+        # Output: True
+        >>> hostname("xn----gtbspbbmkef.xn--p1ai:65535")
+        # Output: True
+        >>> hostname("_example.com")
+        # Output: True
+        >>> hostname("123.5.77.88:31000")
+        # Output: True
+        >>> hostname("12.12.12.12")
+        # Output: True
+        >>> hostname("[::1]:22")
+        # Output: True
+        >>> hostname("dead:beef:0:0:0:0000:42:1")
+        # Output: True
+        >>> hostname("[0:0:0:0:0:ffff:1.2.3.4]:-65538")
+        # Output: ValidationFailure(func=hostname, ...)
+        >>> hostname("[0:&:b:c:@:e:f::]:9999")
+        # Output: ValidationFailure(func=hostname, ...)
+
+    Args:
+        value:
+            Hostname string to validate.
+        may_have_port:
+            Hostname string may contain port number.
+        skip_ip_addr:
+            When hostname string cannot be an IP address.
+        maybe_simple:
+            Hostname string maybe only hyphens and alpha-numerals.
+        rfc_1034:
+            Allow trailing dot in domain/host name.
+            Ref: [RFC 1034](https://www.rfc-editor.org/rfc/rfc1034).
+        rfc_2782:
+            Domain/Host name is of type service record.
+            Ref: [RFC 2782](https://www.rfc-editor.org/rfc/rfc2782).
+
+    Returns:
+        (Literal[True]):
+            If `value` is a valid hostname.
+        (ValidationFailure):
+            If `value` is an invalid hostname.
+
+    > *New in version 0.21.0*.
+    """
+    if may_have_port:
+        if value.count("]:") == 1 and not skip_ip_addr:
+            host_seg, port_seg = value.rsplit(":", 1)
+            return _port_regex().match(f":{port_seg}") and ipv6(
+                host_seg.lstrip("[").rstrip("]"), cidr=False
+            )
+        if value.count(":") == 1:
+            host_seg, port_seg = value.rsplit(":", 1)
+            return _port_regex().match(f":{port_seg}") and (
+                (_simple_hostname_regex().match(host_seg) if maybe_simple else False)
+                or domain(host_seg, rfc_1034=rfc_1034, rfc_2782=rfc_2782)
+                or (False if skip_ip_addr else ipv4(host_seg, cidr=False))
+            )
+
+    return (
+        (_simple_hostname_regex().match(value) if maybe_simple else False)
+        or domain(value, rfc_1034=rfc_1034, rfc_2782=rfc_2782)
+        or (False if skip_ip_addr else ipv4(value, cidr=False))
+        or (False if skip_ip_addr else ipv6(value, cidr=False))
+    )