jsxc: Allow disabling the app

Closes: #1872.

Previously, JSXC can't be disabled and it's shortcut appears on the homepage
forever. Use the EnableState component which stores a flag in the sqlite
database to maintain the status of app being enabled.

Tests:

- Enable/disable button appears. Enabling/disabling the app updates the status
currently.

- Enabling the app shows icon on the homepage and disabling removes it.

- Enabling shows the menu item in the apps page as enabled. Disabling shows the
menu item in the apps page as disabled.

- It is possible the uninstall the app. When app is uninstall it is removed from
homepage and shows as disabled in the apps page.

- When app is disabled or uninstalled, trying to visit the
/plinth/apps/jsxc/jsxc/ throws a 404 error.

- Run functional tests.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
[jvalleroy: Enable JSXC for Ejabberd test]
Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/ejabberd/tests/test_functional.py

@@ -54,6 +54,7 @@ class TestEjabberdApp(functional.BaseAppTests):
     def test_backup_restore(self, session_browser):
         """Test backup and restore of app data."""
         functional.app_enable(session_browser, 'ejabberd')
+        functional.app_enable(session_browser, 'jsxc')
         _jsxc_add_contact(session_browser)
         functional.backup_create(session_browser, 'ejabberd', 'test_ejabberd')
 

plinth/modules/jsxc/__init__.py

@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""
-FreedomBox app to configure XMPP web client/jsxc.
-"""
+"""FreedomBox app to configure XMPP web client/jsxc."""
 
 import logging
 
@@ -32,8 +30,6 @@ class JSXCApp(app_module.App):
 
     _version = 1
 
-    can_be_disabled = False
-
     def __init__(self):
         """Create components for the app."""
         super().__init__()
@@ -50,6 +46,9 @@ class JSXCApp(app_module.App):
                               parent_url_name='apps')
         self.add(menu_item)
 
+        enable_state = app_module.EnableState('enable-state-jsxc')
+        self.add(enable_state)
+
         shortcut = frontpage.Shortcut('shortcut-jsxc', name=info.name,
                                       short_description=info.short_description,
                                       icon=info.icon_filename,

plinth/modules/jsxc/tests/test_functional.py

@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""
-Functional, browser based tests for jsxc app.
-"""
+"""Functional, browser based tests for jsxc app."""
 
 import pytest
 
@@ -10,21 +8,5 @@ from plinth.tests import functional
 pytestmark = [pytest.mark.apps, pytest.mark.jsxc]
 
 
-@pytest.fixture(scope='module', autouse=True)
-def fixture_background(session_browser):
-    """Login."""
-    functional.login(session_browser)
-
-
-def test_install(session_browser):
-    """Test installing the app."""
-    functional.install(session_browser, 'jsxc')
-    assert functional.is_available(session_browser, 'jsxc')
-
-
-@pytest.mark.backups
-def test_backup(session_browser):
-    """Test backing up and restoring."""
-    functional.backup_create(session_browser, 'jsxc', 'test_jsxc')
-    functional.backup_restore(session_browser, 'jsxc', 'test_jsxc')
-    assert functional.is_available(session_browser, 'jsxc')
+class TestJSXCApp(functional.BaseAppTests):
+    app_name = 'jsxc'

plinth/modules/jsxc/views.py

@@ -1,17 +1,26 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""
-Views for the JSXC module
-"""
+"""Views for the JSXC module."""
 
+from django.http import Http404
 from django.views.generic import TemplateView
 
+import plinth.app as app_module
 from plinth.modules import config
 
 
 class JsxcView(TemplateView):
     """A simple page to embed Javascript XMPP Client library."""
+
     template_name = 'jsxc_launch.html'
 
+    def dispatch(self, request, *args, **kwargs):
+        """Don't serve the view when app is disabled."""
+        app = app_module.App.get('jsxc')
+        if not app.is_enabled():
+            raise Http404
+
+        return super().dispatch(request, *args, **kwargs)
+
     def get_context_data(self, *args, **kwargs):
         """Add domain information to view context."""
         context = super().get_context_data(*args, **kwargs)

plinth/tests/functional/__init__.py

@@ -157,7 +157,7 @@ def is_available(browser, site_name):
     browser.visit(url_to_visit)
     time.sleep(3)
     browser.reload()
-    if '404' in browser.title:
+    if '404' in browser.title or 'Page not found' in browser.title:
         return False
 
     # The site might have a default path after the sitename,