[feature] Added configurable setting for API host

Added "OPENWISP_CONTROLLER_API_HOST" for configuring
different host for API endpoints.

.jshintrc

@@ -11,7 +11,8 @@
         "gettext": true,
         "JSONEditor": true,
         "ReconnectingWebSocket": true,
-        "userLanguage": true
+        "userLanguage": true,
+        "owControllerApiHost": true
     },
     "browser": true
 }

openwisp_controller/checks.py

@@ -0,0 +1,51 @@
+from django.conf import settings
+from django.core import checks
+
+from . import settings as app_settings
+
+
+def check_cors_configuration(app_configs, **kwargs):
+    errors = []
+    if not app_settings.OPENWISP_CONTROLLER_API_HOST:
+        return errors
+
+    if not (
+        'corsheaders' in settings.INSTALLED_APPS
+        and 'corsheaders.middleware.CorsMiddleware' in settings.MIDDLEWARE
+    ):
+        errors.append(
+            checks.Warning(
+                msg='Improperly Configured',
+                hint=(
+                    '"django-cors-headers" is either not installed or improperly '
+                    'configured. CORS configuration is required for using '
+                    '"OPENWISP_CONTROLLER_API_HOST" settings. '
+                    ' Configure equivalent CORS rules on your server '
+                    'if you are not using "django-cors-headers".'
+                ),
+                obj='Settings',
+            )
+        )
+    return errors
+
+
+def check_openwisp_controller_ctx_processor(app_config, **kwargs):
+    errors = []
+    ctx_processor = 'openwisp_controller.context_processors.controller_api_settings'
+
+    if not app_settings.OPENWISP_CONTROLLER_API_HOST:
+        return errors
+
+    if not (ctx_processor in settings.TEMPLATES[0]['OPTIONS']['context_processors']):
+        errors.append(
+            checks.Warning(
+                msg='Improperly Configured',
+                hint=(
+                    f'"{ctx_processor} is absent from context processors.'
+                    'It is required to be added in TEMPLATES["context_processor"] '
+                    'for "OPENWISP_CONTROLLER_API_HOST" to work properly.'
+                ),
+                obj='Settings',
+            )
+        )
+    return errors

openwisp_controller/config/templates/admin/config/change_form.html

@@ -10,6 +10,17 @@
 {% endif %}
 {% endblock %}
 
+{% block extrahead %}
+    <script>
+    {% if OPENWISP_CONTROLLER_API_HOST %}
+        const owControllerApiHost = new URL('{{ OPENWISP_CONTROLLER_API_HOST }}');
+    {% else %}
+        const owControllerApiHost = window.location;
+    {% endif %}
+    </script>
+   {{ block.super}}
+{% endblock extrahead %}
+
 {% block object-tools-items %}
 <li>
     {% if download_url %}

openwisp_controller/connection/static/connection/js/commands.js

@@ -5,7 +5,7 @@ var interpolate = interpolate || function(){};
 
 const deviceId = getObjectIdFromUrl();
 const commandWebSocket = new ReconnectingWebSocket(
-    `${getWebSocketProtocol()}${location.host}/ws/device/${getObjectIdFromUrl()}/command`,
+    `${getWebSocketProtocol()}${owControllerApiHost.host}/ws/device/${getObjectIdFromUrl()}/command`,
     null, {
         debug: false
     }
@@ -326,7 +326,7 @@ function initCommandOverlay($) {
         };
         $.ajax({
             type: 'POST',
-            url: `/api/v1/device/${deviceId}/command/`,
+            url: `${owControllerApiHost.origin}/api/v1/device/${deviceId}/command/`,
             headers: {
                 'X-CSRFToken': $('input[name="csrfmiddlewaretoken"]').val()
             },

openwisp_controller/connection/tests/test_admin.py

@@ -1,10 +1,13 @@
 import json
+from unittest.mock import patch
 
-from django.test import TestCase
+from django.test import TestCase, override_settings
 from django.urls import reverse
 from swapper import load_model
 
+from ... import settings as module_settings
 from ...config.tests.test_admin import TestAdmin as TestConfigAdmin
+from ...tests import _get_updated_templates_settings
 from ...tests.utils import TestAdminMixin
 from ..connectors.ssh import Ssh
 from ..widgets import CredentialsSchemaWidget
@@ -176,5 +179,19 @@ def test_commands_schema_view(self):
         self.assertIn('change_password', result)
         self.assertIn('reboot', result)
 
+    @patch.object(
+        module_settings, 'OPENWISP_CONTROLLER_API_HOST', 'https://example.com',
+    )
+    def test_notification_host_setting(self, ctx_processors=[]):
+        url = reverse(
+            f'admin:{self.config_app_label}_device_change', args=(self.device.id,)
+        )
+        with override_settings(
+            TEMPLATES=_get_updated_templates_settings(ctx_processors)
+        ):
+            response = self.client.get(url)
+            self.assertContains(response, 'https://example.com')
+            self.assertNotContains(response, 'owControllerApiHost = window.location')
+
 
 del TestConfigAdmin

openwisp_controller/context_processors.py

@@ -0,0 +1,7 @@
+from . import settings as app_settings
+
+
+def controller_api_settings(request):
+    return {
+        'OPENWISP_CONTROLLER_API_HOST': app_settings.OPENWISP_CONTROLLER_API_HOST,
+    }

openwisp_controller/settings.py

@@ -0,0 +1,3 @@
+from django.conf import settings
+
+OPENWISP_CONTROLLER_API_HOST = getattr(settings, 'OPENWISP_CONTROLLER_API_HOST', None)

openwisp_controller/tests/__init__.py

@@ -0,0 +1,14 @@
+from django.conf import settings
+
+from openwisp_utils.utils import deepcopy
+
+
+def _get_updated_templates_settings(context_processors=[]):
+    template_settings = deepcopy(settings.TEMPLATES[0])
+    if len(context_processors):
+        template_settings['OPTIONS']['context_processors'].extend(context_processors)
+    else:
+        template_settings['OPTIONS']['context_processors'].append(
+            'openwisp_controller.context_processors.controller_api_settings'
+        )
+    return [template_settings]

openwisp_controller/tests/test_utilities.py

@@ -0,0 +1,47 @@
+from unittest.mock import patch
+
+from django.test import TestCase, override_settings
+
+from .. import checks, context_processors
+from .. import settings as app_settings
+from . import _get_updated_templates_settings
+
+
+class TestUtilities(TestCase):
+    @patch.object(
+        app_settings, 'OPENWISP_CONTROLLER_API_HOST', 'https://example.com',
+    )
+    def test_cors_not_configured_check(self):
+        error_message = '"django-cors-headers" is either not installed or improperly'
+
+        def run_check():
+            return checks.check_cors_configuration(None).pop()
+
+        with self.subTest('Test "django-cors-headers" absent in INSTALLED_APPS'):
+            error = run_check()
+            self.assertIn(error_message, error.hint)
+
+        with self.subTest('Test "django-cors-headers" middleware not configured'):
+            error = run_check()
+            self.assertIn(error_message, error.hint)
+
+    @patch.object(
+        app_settings, 'OPENWISP_CONTROLLER_API_HOST', 'https://example.com',
+    )
+    def test_openwisp_controller_context_processor_check(self):
+        def runcheck():
+            return checks.check_openwisp_controller_ctx_processor(None).pop()
+
+        error_message = 'absent from context processor'
+        error = runcheck()
+        self.assertIn(error_message, error.hint)
+
+    @patch.object(
+        app_settings, 'OPENWISP_CONTROLLER_API_HOST', 'https://example.com',
+    )
+    def test_openwisp_controller_context_processor(self):
+        with override_settings(TEMPLATES=_get_updated_templates_settings()):
+            context = {
+                'OPENWISP_CONTROLLER_API_HOST': 'https://example.com',
+            }
+            self.assertEqual(context_processors.controller_api_settings(None), context)

tests/openwisp2/sample_connection/tests.py

@@ -28,12 +28,6 @@ class TestConnectionAdmin(BaseTestConnectionAdmin):
 class TestCommandInlines(BaseTestCommandInlines):
     config_app_label = 'sample_config'
 
-    def test_notification_host_setting(self):
-        # TODO: Fix this failing test
-        # ctx_processor = 'openwisp2.context_processors.controller_api_settings'
-        # super().test_notification_host_setting([ctx_processor])
-        pass
-
 
 class TestModels(BaseTestModels):
     app_label = 'sample_connection'