MDL-67753 registration: Enable Push Notifications when site register

There are some changes to make this possible:
- Enable by default the Mobile notifications plugin
- Implement a new callback for core -> plugins communication
- Generate an Airnotifier access key in the callback when needed

admin/tool/mobile/tests/api_test.php

@@ -78,15 +78,7 @@ class tool_mobile_api_testcase extends externallib_advanced_testcase {
         $CFG->debugdisplay = 1;
         set_config('debugauthdb', 1, 'auth_db');
         set_config('debugdb', 1, 'enrol_database');
-        $expectedissues = array('nohttpsformobilewarning', 'invaliduserquotawarning', 'adodbdebugwarning', 'displayerrorswarning',
-            'mobilenotificationsdisabledwarning');
-
-        $processors = get_message_processors();
-        foreach ($processors as $processor => $status) {
-            if ($processor == 'airnotifier' && $status->enabled) {
-                unset($expectedissues['mobilenotificationsdisabledwarning']);
-            }
-        }
+        $expectedissues = array('nohttpsformobilewarning', 'invaliduserquotawarning', 'adodbdebugwarning', 'displayerrorswarning');
 
         $issues = api::get_potential_config_issues();
         $this->assertCount(count($expectedissues), $issues);

lib/classes/hub/registration.php

@@ -362,6 +362,14 @@ class registration {
             api::update_registration($siteinfo);
             self::$registration = null;
         }
+
+        // Finally, allow other plugins to perform actions once a site is registered for first time.
+        $pluginsfunction = get_plugins_with_function('post_site_registration_confirmed');
+        foreach ($pluginsfunction as $plugins) {
+            foreach ($plugins as $pluginfunction) {
+                $pluginfunction($registration->id);
+            }
+        }
     }
 
     /**

message/output/airnotifier/classes/manager.php

@@ -34,6 +34,9 @@ defined('MOODLE_INTERNAL') || die;
  */
 class message_airnotifier_manager {
 
+    /** @var string The Airnotifier public instance URL */
+    const AIRNOTIFIER_PUBLICURL = 'https://messages.moodle.net';
+
     /**
      * Include the relevant javascript and language strings for the device
      * toolbox YUI module

message/output/airnotifier/db/install.php

@@ -32,7 +32,6 @@ function xmldb_message_airnotifier_install() {
 
     $provider = new stdClass();
     $provider->name = 'airnotifier';
-    $provider->enabled = 0;
     $DB->insert_record('message_processors', $provider);
 
     return $result;

message/output/airnotifier/lib.php

@@ -0,0 +1,50 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Callbacks for message_airnotifier.
+ *
+ * @package    message_airnotifier
+ * @category   external
+ * @copyright  2020 Moodle Pty Ltd <juan@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @since Moodle 3.9
+ */
+
+/**
+ * Callback for when a site is first registered. The function generates an Airnotifier accesskey for the new site.
+ *
+ * @param  int $registrationid the new registration id (registration_hubs table)
+ */
+function message_airnotifier_post_site_registration_confirmed(int $registrationid) {
+    global $CFG;
+
+    // Do nothing if the site already has an Airnotifier access key configured.
+    if (!empty($CFG->airnotifieraccesskey)) {
+        return;
+    }
+
+    $manager = new message_airnotifier_manager();
+
+    // Do nothing for custom Airnotifier instances.
+    if (strpos($CFG->airnotifierurl, $manager::AIRNOTIFIER_PUBLICURL) === false ) {
+        return;
+    }
+
+    if ($key = $manager->request_accesskey()) {
+        set_config('airnotifieraccesskey', $key);
+    }
+}

message/output/airnotifier/requestaccesskey.php

@@ -24,8 +24,6 @@
 
 require('../../../config.php');
 
-define('AIRNOTIFIER_PUBLICURL', 'https://messages.moodle.net');
-
 $PAGE->set_url(new moodle_url('/message/output/airnotifier/requestaccesskey.php'));
 $PAGE->set_context(context_system::instance());
 
@@ -48,7 +46,7 @@ $msg = "";
 
 // If we are requesting a key to the official message system, verify first that this site is registered.
 // This check is also done in Airnotifier.
-if (strpos($CFG->airnotifierurl, AIRNOTIFIER_PUBLICURL) !== false ) {
+if (strpos($CFG->airnotifierurl, message_airnotifier_manager::AIRNOTIFIER_PUBLICURL) !== false ) {
     $adminrenderer = $PAGE->get_renderer('core', 'admin');
     $msg = $adminrenderer->warn_if_not_registered();
     if ($msg) {

message/output/airnotifier/settings.php

@@ -27,7 +27,8 @@ if ($ADMIN->fulltree) {
     // The processor should be enabled by the same enable mobile setting.
     $settings->add(new admin_setting_configtext('airnotifierurl',
                     get_string('airnotifierurl', 'message_airnotifier'),
-                    get_string('configairnotifierurl', 'message_airnotifier'), 'https://messages.moodle.net', PARAM_URL));
+                    get_string('configairnotifierurl', 'message_airnotifier'), message_airnotifier_manager::AIRNOTIFIER_PUBLICURL,
+                    PARAM_URL));
     $settings->add(new admin_setting_configtext('airnotifierport',
                     get_string('airnotifierport', 'message_airnotifier'),
                     get_string('configairnotifierport', 'message_airnotifier'), 443, PARAM_INT));