From bc17a5d4581cbaff541e6a0af47853b0e8ead3a9 Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Mon, 27 Mar 2023 21:29:52 +0200
Subject: [PATCH] init

---
 .gitignore       |  3 ++
 README.md        | 24 +++++++++++++
 main.py          | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
 requirements.txt |  1 +
 4 files changed, 116 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100644 main.py
 create mode 100644 requirements.txt

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d1e11b9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/.idea/
+/cfg/
+/venv/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..f2a1890
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+# netcup DNS
+
+Update DNS records with your current external IP address using the netcup DNS API.
+
+## TODOs
+
+Alternative external IP detection:
+
+```python
+def external_ip_upnp():
+    """
+    https://stackoverflow.com/a/41385033
+
+    Didn't work for me. Even after double checking fritz.box settings:
+
+    fritz.box > Heimnetz > Netzwerk > Statusinformationen über UPnP übertragen
+    """
+    import miniupnpc
+    u = miniupnpc.UPnP()
+    u.discoverdelay = 1000
+    u.discover()
+    u.selectigd()
+    print('external ip address: {}'.format(u.externalipaddress()))
+```
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..98e1a62
--- /dev/null
+++ b/main.py
@@ -0,0 +1,88 @@
+import configparser
+import ipaddress
+from pathlib import Path
+
+import requests
+from nc_dnsapi import Client, DNSRecord
+
+
+def main():
+    """
+    https://github.com/nbuchwitz/nc_dnsapi
+    """
+    destination = external_ipv4()
+
+    files = [file for file in Path('cfg').iterdir() if file.name.endswith('.cfg') and file.is_file()]
+    for file in files:
+        cfg = configparser.ConfigParser()
+        cfg.read(file)
+        customer = cfg['credentials']['customer']
+        api_key = cfg['credentials']['api_key']
+        api_password = cfg['credentials']['api_password']
+
+        domains = [section for section in cfg.sections() if section != 'credentials']
+
+        with Client(customer, api_key, api_password) as api:
+            for domain in domains:
+                hostname = cfg[domain]['hostname']
+                type_ = cfg[domain]['type']
+                update_record_destination(api, domain, hostname, type_, destination)
+
+
+def update_record_destination(api: Client, domain: str, hostname: str, type_: str, destination: str) -> None:
+    record = get_record(api, domain, hostname, type_)
+    record.destination = destination
+    api.update_dns_record(domain, record)
+
+
+def get_record(api: Client, domain: str, hostname: str, type_: str) -> DNSRecord:
+    records: list[DNSRecord] = api.dns_records(domain)
+    record: DNSRecord
+
+    matches = [record for record in records if record.hostname == hostname and record.type == type_]
+    if len(matches) != 1:
+        raise Exception(f'Expected one DNSRecord for {hostname}.{domain}, but got {len(matches)}')
+    return matches[0]
+
+
+def external_ipv4() -> str:
+    """
+    :return: Public IPv4 address
+    """
+
+    # IPv4 only.
+    endpoints = ['https://checkipv4.dedyn.io/', 'https://api.ipify.org', 'https://v4.ident.me/']
+    # Not sure if they return IPv4 addresses only,
+    # so we try these endpoints last.
+    endpoints += ['https://ipinfo.io/ip']
+
+    for endpoint in endpoints:
+        backup = None
+        try:
+            # Force the usage of IPv4
+            # https://stackoverflow.com/a/72440253/6334421
+            #
+            # Alternatively, use urllib3: https://stackoverflow.com/a/46972341/6334421
+            backup = requests.packages.urllib3.util.connection.HAS_IPV6
+            requests.packages.urllib3.util.connection.HAS_IPV6 = False
+
+            # Timeout after 5 seconds.
+            ip = requests.get(endpoint, timeout=5).text.strip()
+            # Check if it is actually an IPv4 address.
+            # Some services, such as e.g. v4.ident.me, sometimes return IPv6.
+            ipv4 = ipaddress.ip_address(ip)
+            if not isinstance(ipv4, ipaddress.IPv4Address):
+                continue
+            # Return ip address as string.
+            return ipv4.exploded
+        except Exception as _e:
+            continue
+        finally:
+            # Allow usage of IPv6 again.
+            if backup is not None:
+                requests.packages.urllib3.util.connection.HAS_IPV6 = backup
+    raise Exception('Could not determine public IPv4 address.')
+
+
+if __name__ == '__main__':
+    main()
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..c4bd0b6
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+nc-dnsapi