Initial commit

README.md

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+# ddns-cloudflare
+
+Self-hosted DDNS service for receiving public IP updates from a router or other local source
+and updating a DNS record in Cloudflare.
+
+The primary purposes for building yet another DDNS tool for updating Cloudflare records:
+- Many other solutions depend upon using a `Global` API token which is unacceptable for this singular purpose. This solution allows the use of a API token scoped with privileges to edit a single DNS zone.
+  - Unforunately Cloudflare does not allow limiting the edit privileges to a single DNS record in a zone at this point.
+- Self-hosted option for receving DDNS updates from a router or other local source rather than depending on querying an external API for public IP address changes
+
+Valid response codes were gathered from here:
+  https://github.com/troglobit/inadyn/blob/master/plugins/common.c
+
+This service requires a GET request in the following format
+
+    https://<username>:<password>@ddns.example.com/update?hostname=<dns record to update>&ip=<public ip>

app.py

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+#!/usr/bin/python3
+
+import CloudFlare
+import os
+from flask import Flask, request
+from flask_httpauth import HTTPBasicAuth
+from werkzeug.security import generate_password_hash, check_password_hash
+
+app = Flask(__name__)
+auth = HTTPBasicAuth()
+
+# Set variables from environment variables
+auth_user = os.environ.get('AUTH_USER', None)
+auth_pass = os.environ.get('AUTH_PASS', None)
+api_token = os.environ.get('API_TOKEN', None)
+
+users = {
+    auth_user: generate_password_hash(auth_pass)
+}
+
+@auth.verify_password
+def verify_password(username, password):
+    if username in users and \
+            check_password_hash(users.get(username), password):
+        return username
+
+@auth.error_handler
+def unauthorized():
+    return "badauth"
+
+@app.route('/update')
+@auth.login_required
+def main():
+    # Set hostname variable
+    if 'hostname' in request.args:
+        hostname = request.args.get('hostname')
+    else:
+        hostname = 'blank'
+
+    # Set ip variable
+    if 'ip' in request.args:
+        ip = request.args.get('ip')
+    else:
+        ip = 'blank'
+
+    # Test inputs to determine the next step
+    if hostname == 'blank':
+        return "nohost"
+    elif ip == 'blank':
+        return "noip"
+    else:
+        response = check_cloudflare(hostname, ip)
+        return(response)
+
+# Cloudflare Functions
+def check_cloudflare(hostname, ip):
+    record_name = hostname
+    record_type = 'A'
+
+    # Determine the DNS zone from the supplied hostname
+    hostname_split = hostname.split('.')
+    zone_name = '.'.join(hostname_split[1:])
+
+    # Initialize the Cloudflare API
+    cf = CloudFlare.CloudFlare(token=api_token)
+
+    # Get the DNS zone ID
+    try:
+        zones = cf.zones.get(params={'name': zone_name})
+        if len(zones) == 0:
+            log_msg('Zone not found')
+        zone_id = zones[0]['id']
+    except CloudFlare.exceptions.CloudFlareAPIError as e:
+        log_msg('/zones.get %d %s' % (e, e))
+
+    # Get the DNS record ID
+    try:
+        dns_records = cf.zones.dns_records.get(zone_id, params={'name': record_name, 'type': record_type})
+        if len(dns_records) == 0:
+            log_msg('DNS record not found')
+        record_id = dns_records[0]['id']
+        record_content = dns_records[0]['content']
+        record_ttl = dns_records[0]['ttl']
+    except CloudFlare.exceptions.CloudFlareAPIError as e:
+        log_msg('/zones.dns_records.get %d %s' % (e, e))
+
+    # Test if the record needs updating
+    if record_content != ip:
+        log_msg("A DNS record update is needed for " + record_name)
+
+        # Update the DNS record
+        dns_record = {
+            'type': record_type,
+            'name': record_name,
+            'content': ip,
+            'ttl': 60
+        }
+
+        try:
+            cf.zones.dns_records.put(zone_id, record_id, data=dns_record)
+            log_msg('DNS record updated successfully: ' + record_name + "(" + ip + ")")
+        except CloudFlare.exceptions.CloudFlareAPIError as e:
+            log_msg('/zones.dns_records.put %d %s' % (e, e))
+            return "dnserr"
+
+        return("good " + ip)
+    else:
+        return("nochg " + ip)
+
+def log_msg(msg):
+    print(msg)
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=8080, debug=True)