Absolute DNS lookups

check.py

@@ -11,7 +11,33 @@ from email.mime.text import MIMEText
 from email.utils import formatdate, make_msgid
 
 import requests
+from requests.adapters import HTTPAdapter
 from urllib3.exceptions import InsecureRequestWarning  # type: ignore
+from urllib3.util.url import parse_url  # type: ignore
+
+
+class AbsoluteDNSAdapter(HTTPAdapter):
+    """A custom adapter for requests to ensure hostnames are treated as absolute."""
+
+    def add_dot_to_hostname(self, url: str) -> str:
+        """Append a dot to the hostname to treat it as an absolute domain name."""
+        parsed_url = parse_url(url)
+
+        # Append a dot to the hostname if it's not already there.
+        hostname = parsed_url.host
+        if not hostname.endswith("."):
+            hostname += "."
+
+        # Reconstruct the URL with the modified hostname.
+        new_url: str = parsed_url._replace(host=hostname).url
+        return new_url
+
+    def send(self, request, **kwargs):  # type: ignore
+        """Override the send method to modify the request URL before sending."""
+        # Modify the request URL to ensure the hostname is treated as absolute.
+        request.url = self.add_dot_to_hostname(request.url)
+        return super().send(request, **kwargs)
+
 
 config_file_path = os.path.expanduser(
     os.path.join(
@@ -35,6 +61,12 @@ headers = {"User-Agent": AGENT, "Accept": "text/html"}
 s = requests.Session()
 s.headers.update(headers)
 
+# Create a session and mount the custom adapter for both HTTP and HTTPS requests.
+adapter = AbsoluteDNSAdapter()
+s.mount("http://", adapter)
+s.mount("https://", adapter)
+
+
 MAIL_FROM = "edward@4angle.com"
 MAIL_TO_NAME = "Edward Betts"
 MAIL_TO_ADDRESS = "edward@4angle.com"