privacy: Add option in UI to set lookup URL for public IPs

- This will act as centralized location to set the URL to lookup IP addresses.

Tests:

- When no value is set initially, the URL for Foundation is shown. This also
happens when the value is removed from 'plinth_kvstore' sqlite3 table.

- When empty value is set it, the empty value is set in DB and show in the UI.

- When no value is changed and form is updated, message is shown that settings
have not changed.

- When value is changed and form is updated the updated value is shown in the
form, message is shown that configuration has been updated.

- Updated URL value reflects in the email app and errors change accordingly.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Benedek Nagy <contact@nbenedek.me>

plinth/modules/privacy/__init__.py

@@ -9,7 +9,7 @@ from django.utils.translation import gettext_lazy as _
 from django.utils.translation import gettext_noop
 
 from plinth import app as app_module
-from plinth import menu
+from plinth import kvstore, menu
 from plinth.config import DropinConfigs
 from plinth.modules.backups.components import BackupRestore
 from plinth.package import Packages
@@ -94,7 +94,13 @@ def _show_privacy_notification():
 
 def get_ip_lookup_url():
     """Return the URL to use to lookup external IP address."""
-    return 'https://ddns.freedombox.org/ip/'
+    return kvstore.get_default('ip_lookup_url',
+                               'https://ddns.freedombox.org/ip/')
+
+
+def set_ip_lookup_url(ip_lookup_url: str):
+    """Set the URL to use to lookup external IP address."""
+    kvstore.set('ip_lookup_url', ip_lookup_url)
 
 
 def lookup_public_address(ip_type: Literal['ipv4', 'ipv6']) -> str:

plinth/modules/privacy/forms.py

@@ -2,6 +2,7 @@
 """FreedomBox privacy app."""
 
 from django import forms
+from django.core import validators
 from django.utils.translation import gettext_lazy as _
 
 from plinth import cfg
@@ -12,6 +13,14 @@ from plinth.utils import format_lazy
 class PrivacyForm(forms.Form):
     """Privacy configuration form."""
 
+    help_ip_lookup_url = format_lazy(
+        _('Optional Value. This URL is used to determine the publicly visible '
+          'IP address of your {box_name}. The URL should simply return the '
+          'IPv4 or IPv6 address where the client request comes from. Default '
+          'is to use the service provided by the FreedomBox Foundation at '
+          'https://ddns.freedombox.org/ip/. If empty, lookups are disabled '
+          'and some functionality will fail.'), box_name=_(cfg.box_name))
+
     enable_popcon = forms.BooleanField(
         label=_('Periodically submit a list of apps used (suggested)'),
         required=False, help_text=format_lazy(
@@ -32,6 +41,11 @@ class PrivacyForm(forms.Form):
             'internet connectivity is available. Can be disabled in most '
             'cases if network connectivity is stable and reliable.'))
 
+    ip_lookup_url = forms.CharField(
+        label=_('URL to look up public IP address'), required=False,
+        help_text=help_ip_lookup_url,
+        validators=[validators.URLValidator(schemes=['http', 'https'])])
+
     def __init__(self, *args, **kwargs):
         """Disable DNS fallback field if necessary."""
         super().__init__(*args, **kwargs)

plinth/modules/privacy/manifest.py

@@ -7,4 +7,4 @@ from . import privileged
 
 backup = {'config': {'files': [str(privileged.CONFIG_FILE)]}}
 
-tags = [_('Usage reporting'), _('Fallback DNS')]
+tags = [_('Usage reporting'), _('External services'), _('Fallback DNS')]

plinth/modules/privacy/views.py

@@ -5,7 +5,7 @@ from django.contrib import messages
 from django.utils.translation import gettext as _
 
 import plinth.modules.names.privileged as names_privileged
-from plinth.modules import names
+from plinth.modules import names, privacy
 from plinth.modules.privacy.forms import PrivacyForm
 from plinth.views import AppView
 
@@ -22,6 +22,7 @@ class PrivacyAppView(AppView):
         """Return the values to fill in the form."""
         initial = super().get_initial()
         initial.update(privileged.get_configuration())
+        initial['ip_lookup_url'] = privacy.get_ip_lookup_url()
         if names.is_resolved_installed():
             initial.update(names_privileged.get_resolved_configuration())
 
@@ -43,6 +44,10 @@ class PrivacyAppView(AppView):
                     dns_fallback=new_config['dns_fallback'])
                 is_changed = True
 
+        if old_config['ip_lookup_url'] != new_config['ip_lookup_url']:
+            privacy.set_ip_lookup_url(new_config['ip_lookup_url'])
+            is_changed = True
+
         if changes:
             privileged.set_configuration(**changes)