MOBILE-2853 core: Let app DB tables define a scheme to handle updates

src/classes/site.ts

@@ -170,7 +170,7 @@ interface RequestQueueItem {
 /**
  * Class that represents a site (combination of site + user).
  * It will have all the site data and provide utility functions regarding a site.
- * To add tables to the site's database, please use CoreSitesProvider.createTablesFromSchema. This will make sure that
+ * To add tables to the site's database, please use CoreSitesProvider.registerSiteSchema. This will make sure that
  * the tables are created in all the sites, not just the current one.
  */
 export class CoreSite {

src/core/emulator/providers/local-notifications.ts

@@ -14,10 +14,10 @@
 
 import { Injectable } from '@angular/core';
 import { LocalNotifications, ILocalNotification, ILocalNotificationAction } from '@ionic-native/local-notifications';
-import { CoreAppProvider } from '@providers/app';
+import { CoreAppProvider, CoreAppSchema } from '@providers/app';
 import { CoreTextUtilsProvider } from '@providers/utils/text';
 import { CoreUtilsProvider } from '@providers/utils/utils';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 import { CoreConstants } from '@core/constants';
 import { CoreConfigConstants } from '../../../configconstants';
 import * as moment from 'moment';
@@ -43,7 +43,11 @@ export class LocalNotificationsMock extends LocalNotifications {
 
     // Variables for database.
     protected DESKTOP_NOTIFS_TABLE = 'desktop_local_notifications';
-    protected tableSchema: SQLiteDBTableSchema = {
+    protected tableSchema: CoreAppSchema = {
+        name: 'LocalNotificationsMock',
+        version: 1,
+        tables: [
+            {
                 name: this.DESKTOP_NOTIFS_TABLE,
                 columns: [
                     {
@@ -71,13 +75,16 @@ export class LocalNotificationsMock extends LocalNotifications {
                         name: 'triggered',
                         type: 'INTEGER'
                     }
-        ]
+                ],
+            },
+        ],
     };
 
     protected appDB: SQLiteDB;
     protected scheduled: { [i: number]: any } = {};
     protected triggered: { [i: number]: any } = {};
     protected observers: {[event: string]: Subject<any>};
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     protected defaults = {
         actions       : [],
         attachments   : [],
@@ -117,7 +124,9 @@ export class LocalNotificationsMock extends LocalNotifications {
         super();
 
         this.appDB = appProvider.getDB();
-        this.appDB.createTableFromSchema(this.tableSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.tableSchema).catch(() => {
+            // Ignore errors.
+        });
 
         // Initialize observers.
         this.observers = {
@@ -550,8 +559,10 @@ export class LocalNotificationsMock extends LocalNotifications {
      *
      * @return Promise resolved with the notifications.
      */
-    protected getAllNotifications(): Promise<any> {
+    protected async getAllNotifications(): Promise<any> {
-        return this.appDB.getAllRecords(this.DESKTOP_NOTIFS_TABLE).then((notifications) => {
+        await this.dbReady;
+
+        const notifications = await this.appDB.getAllRecords(this.DESKTOP_NOTIFS_TABLE);
         notifications.forEach((notification) => {
             notification.trigger = {
                 at: new Date(notification.at)
@@ -563,7 +574,6 @@ export class LocalNotificationsMock extends LocalNotifications {
         });
 
         return notifications;
-        });
     }
 
     /**
@@ -889,7 +899,9 @@ export class LocalNotificationsMock extends LocalNotifications {
      * @param id ID of the notification.
      * @return Promise resolved when done.
      */
-    protected removeNotification(id: number): Promise<any> {
+    protected async removeNotification(id: number): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.deleteRecords(this.DESKTOP_NOTIFS_TABLE, { id: id });
     }
 
@@ -979,7 +991,9 @@ export class LocalNotificationsMock extends LocalNotifications {
      * @param triggered Whether the notification has been triggered.
      * @return Promise resolved when stored.
      */
-    protected storeNotification(notification: ILocalNotification, triggered: boolean): Promise<any> {
+    protected async storeNotification(notification: ILocalNotification, triggered: boolean): Promise<any> {
+        await this.dbReady;
+
         // Only store some of the properties.
         const entry = {
             id : notification.id,

src/core/pushnotifications/providers/pushnotifications.ts

@@ -18,7 +18,7 @@ import { Badge } from '@ionic-native/badge';
 import { Push, PushObject, PushOptions } from '@ionic-native/push';
 import { Device } from '@ionic-native/device';
 import { TranslateService } from '@ngx-translate/core';
-import { CoreAppProvider } from '@providers/app';
+import { CoreAppProvider, CoreAppSchema } from '@providers/app';
 import { CoreInitDelegate } from '@providers/init';
 import { CoreLoggerProvider } from '@providers/logger';
 import { CoreSitesProvider, CoreSiteSchema } from '@providers/sites';
@@ -31,7 +31,7 @@ import { CoreConfigProvider } from '@providers/config';
 import { CoreConstants } from '@core/constants';
 import { CoreConfigConstants } from '../../../configconstants';
 import { ILocalNotification } from '@ionic-native/local-notifications';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 import { CoreSite } from '@classes/site';
 import { CoreFilterProvider } from '@core/filter/providers/filter';
 import { CoreFilterDelegate } from '@core/filter/providers/delegate';
@@ -84,13 +84,17 @@ export class CorePushNotificationsProvider {
     protected logger;
     protected pushID: string;
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     static COMPONENT = 'CorePushNotificationsProvider';
 
     // Variables for database. The name still contains the name "addon" for backwards compatibility.
     static BADGE_TABLE = 'addon_pushnotifications_badge';
     static PENDING_UNREGISTER_TABLE = 'addon_pushnotifications_pending_unregister';
     static REGISTERED_DEVICES_TABLE = 'addon_pushnotifications_registered_devices';
-    protected appTablesSchema: SQLiteDBTableSchema[] = [
+    protected appTablesSchema: CoreAppSchema = {
+        name: 'CorePushNotificationsProvider',
+        version: 1,
+        tables: [
             {
                 name: CorePushNotificationsProvider.BADGE_TABLE,
                 columns: [
@@ -131,7 +135,8 @@ export class CorePushNotificationsProvider {
                     }
                 ]
             }
-    ];
+        ]
+    };
     protected siteSchema: CoreSiteSchema = {
         name: 'AddonPushNotificationsProvider', // The name still contains "Addon" for backwards compatibility.
         version: 1,
@@ -182,7 +187,9 @@ export class CorePushNotificationsProvider {
             private filterProvider: CoreFilterProvider, private filterDelegate: CoreFilterDelegate) {
         this.logger = logger.getInstance('CorePushNotificationsProvider');
         this.appDB = appProvider.getDB();
-        this.appDB.createTablesFromSchema(this.appTablesSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.appTablesSchema).catch(() => {
+            // Ignore errors.
+        });
         this.sitesProvider.registerSiteSchema(this.siteSchema);
 
         platform.ready().then(() => {
@@ -211,10 +218,14 @@ export class CorePushNotificationsProvider {
      * @param siteId Site ID.
      * @return Resolved when done.
      */
-    cleanSiteCounters(siteId: string): Promise<any> {
+    async cleanSiteCounters(siteId: string): Promise<void> {
-        return this.appDB.deleteRecords(CorePushNotificationsProvider.BADGE_TABLE, {siteid: siteId} ).finally(() => {
+        await this.dbReady;
+
+        try {
+            await this.appDB.deleteRecords(CorePushNotificationsProvider.BADGE_TABLE, {siteid: siteId} );
+        } finally {
             this.updateAppCounter();
-        });
+        }
     }
 
     /**
@@ -532,11 +543,13 @@ export class CorePushNotificationsProvider {
      * @param site Site to unregister from.
      * @return Promise resolved when device is unregistered.
      */
-    unregisterDeviceOnMoodle(site: CoreSite): Promise<any> {
+    async unregisterDeviceOnMoodle(site: CoreSite): Promise<any> {
         if (!site || !this.appProvider.isMobile()) {
             return Promise.reject(null);
         }
 
+        await this.dbReady;
+
         this.logger.debug(`Unregister device on Moodle: '${site.id}'`);
 
         const data = {
@@ -544,9 +557,11 @@ export class CorePushNotificationsProvider {
             uuid:  this.device.uuid
         };
 
-        return site.write('core_user_remove_user_device', data).then((response) => {
+        try {
+            const response = await site.write('core_user_remove_user_device', data);
+
             if (!response || !response.removed) {
-                return Promise.reject(null);
+                throw null;
             }
 
             const promises = [];
@@ -561,24 +576,21 @@ export class CorePushNotificationsProvider {
             return Promise.all(promises).catch(() => {
                 // Ignore errors.
             });
-        }).catch((error) => {
+        } catch (error) {
-            if (this.utils.isWebServiceError(error)) {
+            if (!this.utils.isWebServiceError(error)) {
-                // It's a WebService error, can't unregister.
-                return Promise.reject(error);
-            }
-
                 // Store the pending unregister so it's retried again later.
-            return this.appDB.insertRecord(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {
+                await this.appDB.insertRecord(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {
                     siteid: site.id,
                     siteurl: site.getURL(),
                     token: site.getToken(),
                     info: JSON.stringify(site.getInfo())
-            }).then(() => {
-                return Promise.reject(error);
-            });
                 });
             }
 
+            throw error;
+        }
+    }
+
     /**
      * Update Counter for an addon. It will update the refered siteId counter and the total badge.
      * It will return the updated addon counter.
@@ -724,52 +736,53 @@ export class CorePushNotificationsProvider {
      * @param forceUnregister Whether to force unregister and register.
      * @return Promise resolved when device is registered.
      */
-    registerDeviceOnMoodle(siteId?: string, forceUnregister?: boolean): Promise<any> {
+    async registerDeviceOnMoodle(siteId?: string, forceUnregister?: boolean): Promise<void> {
         this.logger.debug('Register device on Moodle.');
 
         if (!this.canRegisterOnMoodle()) {
             return Promise.reject(null);
         }
 
-        const data = this.getRegisterData();
+        await this.dbReady;
-        let result,
-            site: CoreSite;
 
-        return this.sitesProvider.getSite(siteId).then((s) => {
+        const data = this.getRegisterData();
-            site = s;
+        let result;
+
+        const site = await this.sitesProvider.getSite(siteId);
+
+        try {
 
             if (forceUnregister) {
-                return {unregister: true, register: true};
+                result = {unregister: true, register: true};
             } else {
                 // Check if the device is already registered.
-                return this.shouldRegister(data, site);
+                result = await this.shouldRegister(data, site);
             }
-        }).then((res) => {
-            result = res;
 
             if (result.unregister) {
                 // Unregister the device first.
-                return this.unregisterDeviceOnMoodle(site).catch(() => {
+                await this.unregisterDeviceOnMoodle(site).catch(() => {
                     // Ignore errors.
                 });
             }
-        }).then(() => {
+
             if (result.register) {
                 // Now register the device.
-                return site.write('core_user_add_user_device', this.utils.clone(data)).then((response) => {
+                await site.write('core_user_add_user_device', this.utils.clone(data));
+
                 // Insert the device in the local DB.
-                    return site.getDb().insertRecord(CorePushNotificationsProvider.REGISTERED_DEVICES_TABLE, data)
+                try {
-                            .catch((error) => {
+                    await site.getDb().insertRecord(CorePushNotificationsProvider.REGISTERED_DEVICES_TABLE, data);
+                } catch (err) {
+                    // Ignore errors.
+                }
+            }
+        } finally {
+            // Remove pending unregisters for this site.
+            await this.appDB.deleteRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {siteid: site.id}).catch(() => {
                 // Ignore errors.
-                    });
             });
         }
-        }).finally(() => {
-            // Remove pending unregisters for this site.
-            this.appDB.deleteRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {siteid: site.id}).catch(() => {
-                // Ignore errors.
-            });
-        });
     }
 
     /**
@@ -779,12 +792,16 @@ export class CorePushNotificationsProvider {
      * @param addon Registered addon name. If not defined it will store the site total.
      * @return Promise resolved with the stored badge counter for the addon or site or 0 if none.
      */
-    protected getAddonBadge(siteId?: string, addon: string = 'site'): Promise<any> {
+    protected async getAddonBadge(siteId?: string, addon: string = 'site'): Promise<number> {
-        return this.appDB.getRecord(CorePushNotificationsProvider.BADGE_TABLE, {siteid: siteId, addon: addon}).then((entry) => {
+        await this.dbReady;
+
+        try {
+            const entry = await this.appDB.getRecord(CorePushNotificationsProvider.BADGE_TABLE, {siteid: siteId, addon: addon});
+
             return (entry && entry.number) || 0;
-        }).catch(() => {
+        } catch (err) {
             return 0;
-        });
+        }
     }
 
     /**
@@ -793,30 +810,26 @@ export class CorePushNotificationsProvider {
      * @param siteId If defined, retry only for that site if needed. Otherwise, retry all pending unregisters.
      * @return Promise resolved when done.
      */
-    retryUnregisters(siteId?: string): Promise<any> {
+    async retryUnregisters(siteId?: string): Promise<any> {
-        let promise;
+        await this.dbReady;
+
+        let results;
 
         if (siteId) {
             // Check if the site has a pending unregister.
-            promise = this.appDB.getRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {siteid: siteId});
+            results = await this.appDB.getRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE, {siteid: siteId});
         } else {
             // Get all pending unregisters.
-            promise = this.appDB.getAllRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE);
+            results = await this.appDB.getAllRecords(CorePushNotificationsProvider.PENDING_UNREGISTER_TABLE);
         }
 
-        return promise.then((results) => {
+        return Promise.all(results.map((result) => {
-            const promises = [];
-
-            results.forEach((result) => {
             // Create a temporary site to unregister.
             const tmpSite = this.sitesFactory.makeSite(result.siteid, result.siteurl, result.token,
                     this.textUtils.parseJSON(result.info, {}));
 
-                promises.push(this.unregisterDeviceOnMoodle(tmpSite));
+            return this.unregisterDeviceOnMoodle(tmpSite);
-            });
+        }));
-
-            return Promise.all(promises);
-        });
     }
 
     /**
@@ -827,7 +840,9 @@ export class CorePushNotificationsProvider {
      * @param addon Registered addon name. If not defined it will store the site total.
      * @return Promise resolved with the stored badge counter for the addon or site.
      */
-    protected saveAddonBadge(value: number, siteId?: string, addon: string = 'site'): Promise<any> {
+    protected async saveAddonBadge(value: number, siteId?: string, addon: string = 'site'): Promise<any> {
+        await this.dbReady;
+
         siteId = siteId || this.sitesProvider.getCurrentSiteId();
 
         const entry = {
@@ -836,9 +851,9 @@ export class CorePushNotificationsProvider {
             number: value
         };
 
-        return this.appDB.insertRecord(CorePushNotificationsProvider.BADGE_TABLE, entry).then(() => {
+        await this.appDB.insertRecord(CorePushNotificationsProvider.BADGE_TABLE, entry);
+
         return value;
-        });
     }
 
     /**

src/core/sharedfiles/providers/sharedfiles.ts

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 import { Injectable } from '@angular/core';
-import { CoreAppProvider } from '@providers/app';
+import { CoreAppProvider, CoreAppSchema } from '@providers/app';
 import { CoreEventsProvider } from '@providers/events';
 import { CoreFileProvider } from '@providers/file';
 import { CoreLoggerProvider } from '@providers/logger';
@@ -21,7 +21,7 @@ import { CoreSitesProvider } from '@providers/sites';
 import { CoreMimetypeUtilsProvider } from '@providers/utils/mimetype';
 import { CoreTextUtilsProvider } from '@providers/utils/text';
 import { Md5 } from 'ts-md5/dist/md5';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 
 /**
  * Service to share files with the app.
@@ -32,19 +32,26 @@ export class CoreSharedFilesProvider {
 
     // Variables for the database.
     protected SHARED_FILES_TABLE = 'shared_files';
-    protected tableSchema: SQLiteDBTableSchema = {
+    protected tableSchema: CoreAppSchema = {
+        name: 'CoreSharedFilesProvider',
+        version: 1,
+        tables: [
+            {
                 name: this.SHARED_FILES_TABLE,
                 columns: [
                     {
                         name: 'id',
                         type: 'TEXT',
                         primaryKey: true
-            }
+                    },
-        ]
+                ],
+            },
+        ],
     };
 
     protected logger;
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
 
     constructor(logger: CoreLoggerProvider, private fileProvider: CoreFileProvider, appProvider: CoreAppProvider,
         private textUtils: CoreTextUtilsProvider, private mimeUtils: CoreMimetypeUtilsProvider,
@@ -52,7 +59,9 @@ export class CoreSharedFilesProvider {
         this.logger = logger.getInstance('CoreSharedFilesProvider');
 
         this.appDB = appProvider.getDB();
-        this.appDB.createTableFromSchema(this.tableSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.tableSchema).catch(() => {
+            // Ignore errors.
+        });
     }
 
     /**
@@ -189,7 +198,9 @@ export class CoreSharedFilesProvider {
      * @param fileId File ID.
      * @return Resolved if treated, rejected otherwise.
      */
-    protected isFileTreated(fileId: string): Promise<any> {
+    protected async isFileTreated(fileId: string): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.getRecord(this.SHARED_FILES_TABLE, { id: fileId });
     }
 
@@ -199,12 +210,16 @@ export class CoreSharedFilesProvider {
      * @param fileId File ID.
      * @return Promise resolved when marked.
      */
-    protected markAsTreated(fileId: string): Promise<any> {
+    protected async markAsTreated(fileId: string): Promise<void> {
+        await this.dbReady;
+
+        try {
             // Check if it's already marked.
-        return this.isFileTreated(fileId).catch(() => {
+            await this.isFileTreated(fileId);
+        } catch (err) {
             // Doesn't exist, insert it.
-            return this.appDB.insertRecord(this.SHARED_FILES_TABLE, { id: fileId });
+            await this.appDB.insertRecord(this.SHARED_FILES_TABLE, { id: fileId });
-        });
+        }
     }
 
     /**
@@ -243,7 +258,9 @@ export class CoreSharedFilesProvider {
      * @param fileId File ID.
      * @return Resolved when unmarked.
      */
-    protected unmarkAsTreated(fileId: string): Promise<any> {
+    protected async unmarkAsTreated(fileId: string): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.deleteRecords(this.SHARED_FILES_TABLE, { id: fileId });
     }
 }

src/providers/app.ts

@@ -21,7 +21,7 @@ import { StatusBar } from '@ionic-native/status-bar';
 import { CoreDbProvider } from './db';
 import { CoreLoggerProvider } from './logger';
 import { CoreEventsProvider } from './events';
-import { SQLiteDB } from '@classes/sqlitedb';
+import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
 import { CoreConfigConstants } from '../configconstants';
 
 /**
@@ -49,6 +49,37 @@ export interface CoreRedirectData {
     timemodified?: number;
 }
 
+/**
+ * App DB schema and migration function.
+ */
+export interface CoreAppSchema {
+    /**
+     * Name of the schema.
+     */
+    name: string;
+
+    /**
+     * Latest version of the schema (integer greater than 0).
+     */
+    version: number;
+
+    /**
+     * Tables to create when installing or upgrading the schema.
+     */
+    tables?: SQLiteDBTableSchema[];
+
+    /**
+     * Migrates the schema to the latest version.
+     *
+     * Called when installing and upgrading the schema, after creating the defined tables.
+     *
+     * @param db The affected DB.
+     * @param oldVersion Old version of the schema or 0 if not installed.
+     * @return Promise resolved when done.
+     */
+    migrate?(db: SQLiteDB, oldVersion: number): Promise<any>;
+}
+
 /**
  * Factory to provide some global functionalities, like access to the global app database.
  * @description
@@ -71,12 +102,33 @@ export class CoreAppProvider {
     protected mainMenuOpen: number;
     protected forceOffline = false;
 
+    // Variables for DB.
+    protected createVersionsTableReady: Promise<any>;
+    protected SCHEMA_VERSIONS_TABLE = 'schema_versions';
+    protected versionsTableSchema: SQLiteDBTableSchema = {
+        name: this.SCHEMA_VERSIONS_TABLE,
+        columns: [
+            {
+                name: 'name',
+                type: 'TEXT',
+                primaryKey: true,
+            },
+            {
+                name: 'version',
+                type: 'INTEGER'
+            }
+        ]
+    };
+
     constructor(dbProvider: CoreDbProvider, private platform: Platform, private keyboard: Keyboard, private appCtrl: App,
             private network: Network, logger: CoreLoggerProvider, private events: CoreEventsProvider, zone: NgZone,
             private menuCtrl: MenuController, private statusBar: StatusBar) {
         this.logger = logger.getInstance('CoreAppProvider');
         this.db = dbProvider.getDB(this.DBNAME);
 
+        // Create the schema versions table.
+        this.createVersionsTableReady = this.db.createTableFromSchema(this.versionsTableSchema);
+
         this.keyboard.onKeyboardShow().subscribe((data) => {
             // Execute the callback in the Angular zone, so change detection doesn't stop working.
             zone.run(() => {
@@ -133,6 +185,47 @@ export class CoreAppProvider {
         }
     }
 
+    /**
+     * Install and upgrade a certain schema.
+     *
+     * @param schema The schema to create.
+     * @return Promise resolved when done.
+     */
+    async createTablesFromSchema(schema: CoreAppSchema): Promise<any> {
+        this.logger.debug(`Apply schema to app DB: ${schema.name}`);
+
+        let oldVersion;
+
+        try {
+            // Wait for the schema versions table to be created.
+            await this.createVersionsTableReady;
+
+            // Fetch installed version of the schema.
+            const entry = await this.db.getRecord(this.SCHEMA_VERSIONS_TABLE, {name: schema.name});
+            oldVersion = entry.version;
+        } catch (error) {
+            // No installed version yet.
+            oldVersion = 0;
+        }
+
+        if (oldVersion >= schema.version) {
+            // Version already installed, nothing else to do.
+            return;
+        }
+
+        this.logger.debug(`Migrating schema '${schema.name}' of app DB from version ${oldVersion} to ${schema.version}`);
+
+        if (schema.tables) {
+            await this.db.createTablesFromSchema(schema.tables);
+        }
+        if (schema.migrate) {
+            await schema.migrate(this.db, oldVersion);
+        }
+
+        // Set installed version.
+        await this.db.insertRecord(this.SCHEMA_VERSIONS_TABLE, {name: schema.name, version: schema.version});
+    }
+
     /**
      * Get the application global database.
      *

src/providers/config.ts

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 import { Injectable } from '@angular/core';
-import { CoreAppProvider } from './app';
+import { CoreAppProvider, CoreAppSchema } from './app';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 
 /**
  * Factory to provide access to dynamic and permanent config and settings.
@@ -24,7 +24,11 @@ import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
 export class CoreConfigProvider {
     protected appDB: SQLiteDB;
     protected TABLE_NAME = 'core_config';
-    protected tableSchema: SQLiteDBTableSchema = {
+    protected tableSchema: CoreAppSchema = {
+        name: 'CoreConfigProvider',
+        version: 1,
+        tables: [
+            {
                 name: this.TABLE_NAME,
                 columns: [
                     {
@@ -37,11 +41,17 @@ export class CoreConfigProvider {
                         name: 'value'
                     }
                 ]
+            },
+        ],
     };
 
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
+
     constructor(appProvider: CoreAppProvider) {
         this.appDB = appProvider.getDB();
-        this.appDB.createTableFromSchema(this.tableSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.tableSchema).catch(() => {
+            // Ignore errors.
+        });
     }
 
     /**
@@ -50,7 +60,9 @@ export class CoreConfigProvider {
      * @param name The config name.
      * @return Promise resolved when done.
      */
-    delete(name: string): Promise<any> {
+    async delete(name: string): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.deleteRecords(this.TABLE_NAME, { name: name });
     }
 
@@ -61,16 +73,20 @@ export class CoreConfigProvider {
      * @param defaultValue Default value to use if the entry is not found.
      * @return Resolves upon success along with the config data. Reject on failure.
      */
-    get(name: string, defaultValue?: any): Promise<any> {
+    async get(name: string, defaultValue?: any): Promise<any> {
-        return this.appDB.getRecord(this.TABLE_NAME, { name: name }).then((entry) => {
+        await this.dbReady;
+
+        try {
+            const entry = await this.appDB.getRecord(this.TABLE_NAME, { name: name });
+
             return entry.value;
-        }).catch((error) => {
+        } catch (error) {
             if (typeof defaultValue != 'undefined') {
                 return defaultValue;
             }
 
-            return Promise.reject(error);
+            throw error;
-        });
+        }
     }
 
     /**
@@ -80,7 +96,9 @@ export class CoreConfigProvider {
      * @param value The config value. Can only store number or strings.
      * @return Promise resolved when done.
      */
-    set(name: string, value: number | string): Promise<any> {
+    async set(name: string, value: number | string): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.insertRecord(this.TABLE_NAME, { name: name, value: value });
     }
 }

src/providers/cron.ts

@@ -14,12 +14,12 @@
 
 import { Injectable, NgZone } from '@angular/core';
 import { Network } from '@ionic-native/network';
-import { CoreAppProvider } from './app';
+import { CoreAppProvider, CoreAppSchema } from './app';
 import { CoreConfigProvider } from './config';
 import { CoreLoggerProvider } from './logger';
 import { CoreUtilsProvider } from './utils/utils';
 import { CoreConstants } from '@core/constants';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 
 /**
  * Interface that all cron handlers must implement.
@@ -92,7 +92,11 @@ export class CoreCronDelegate {
 
     // Variables for database.
     protected CRON_TABLE = 'cron';
-    protected tableSchema: SQLiteDBTableSchema = {
+    protected tableSchema: CoreAppSchema = {
+        name: 'CoreCronDelegate',
+        version: 1,
+        tables: [
+            {
                 name: this.CRON_TABLE,
                 columns: [
                     {
@@ -105,10 +109,13 @@ export class CoreCronDelegate {
                         type: 'INTEGER'
                     }
                 ]
+            },
+        ],
     };
 
     protected logger;
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     protected handlers: { [s: string]: CoreCronHandler } = {};
     protected queuePromise = Promise.resolve();
 
@@ -117,7 +124,9 @@ export class CoreCronDelegate {
         this.logger = logger.getInstance('CoreCronDelegate');
 
         this.appDB = this.appProvider.getDB();
-        this.appDB.createTableFromSchema(this.tableSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.tableSchema).catch(() => {
+            // Ignore errors.
+        });
 
         // When the app is re-connected, start network handlers that were stopped.
         network.onConnect().subscribe(() => {
@@ -306,16 +315,19 @@ export class CoreCronDelegate {
      * @param name Handler's name.
      * @return Promise resolved with the handler's last execution time.
      */
-    protected getHandlerLastExecutionTime(name: string): Promise<number> {
+    protected async getHandlerLastExecutionTime(name: string): Promise<number> {
+        await this.dbReady;
+
         const id = this.getHandlerLastExecutionId(name);
 
-        return this.appDB.getRecord(this.CRON_TABLE, { id: id }).then((entry) => {
+        try {
+            const entry = await this.appDB.getRecord(this.CRON_TABLE, { id: id });
             const time = parseInt(entry.value, 10);
 
             return isNaN(time) ? 0 : time;
-        }).catch(() => {
+        } catch (err) {
             return 0; // Not set, return 0.
-        });
+        }
     }
 
     /**
@@ -471,7 +483,9 @@ export class CoreCronDelegate {
      * @param time Time to set.
      * @return Promise resolved when the execution time is saved.
      */
-    protected setHandlerLastExecutionTime(name: string, time: number): Promise<any> {
+    protected async setHandlerLastExecutionTime(name: string, time: number): Promise<any> {
+        await this.dbReady;
+
         const id = this.getHandlerLastExecutionId(name),
             entry = {
                 id: id,

src/providers/filepool.ts

@@ -14,7 +14,7 @@
 
 import { Injectable, NgZone } from '@angular/core';
 import { Network } from '@ionic-native/network';
-import { CoreAppProvider } from './app';
+import { CoreAppProvider, CoreAppSchema } from './app';
 import { CoreEventsProvider } from './events';
 import { CoreFileProvider } from './file';
 import { CoreInitDelegate } from './init';
@@ -28,7 +28,7 @@ import { CoreTextUtilsProvider } from './utils/text';
 import { CoreTimeUtilsProvider } from './utils/time';
 import { CoreUrlUtilsProvider } from './utils/url';
 import { CoreUtilsProvider } from './utils/utils';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 import { CoreConstants } from '@core/constants';
 import { Md5 } from 'ts-md5/dist/md5';
 
@@ -224,7 +224,10 @@ export class CoreFilepoolProvider {
     protected FILES_TABLE = 'filepool_files'; // Downloaded files.
     protected LINKS_TABLE = 'filepool_files_links'; // Links between downloaded files and components.
     protected PACKAGES_TABLE = 'filepool_packages'; // Downloaded packages (sets of files).
-    protected appTablesSchema: SQLiteDBTableSchema[] = [
+    protected appTablesSchema: CoreAppSchema = {
+        name: 'CoreFilepoolProvider',
+        version: 1,
+        tables: [
             {
                 name: this.QUEUE_TABLE,
                 columns: [
@@ -275,7 +278,8 @@ export class CoreFilepoolProvider {
                 ],
                 primaryKeys: ['siteId', 'fileId']
             }
-    ];
+        ]
+    };
     protected siteSchema: CoreSiteSchema = {
         name: 'CoreFilepoolProvider',
         version: 1,
@@ -392,6 +396,7 @@ export class CoreFilepoolProvider {
 
     protected logger;
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     protected tokenRegex = new RegExp('(\\?|&)token=([A-Za-z0-9]*)');
     protected queueState: string;
     protected urlAttributes = [
@@ -415,7 +420,9 @@ export class CoreFilepoolProvider {
         this.logger = logger.getInstance('CoreFilepoolProvider');
 
         this.appDB = this.appProvider.getDB();
-        this.appDB.createTablesFromSchema(this.appTablesSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.appTablesSchema).catch(() => {
+            // Ignore errors.
+        });
 
         this.sitesProvider.registerSiteSchema(this.siteSchema);
 
@@ -567,11 +574,13 @@ export class CoreFilepoolProvider {
      * @param link The link to add for the file.
      * @return Promise resolved when the file is downloaded.
      */
-    protected addToQueue(siteId: string, fileId: string, url: string, priority: number, revision: number, timemodified: number,
+    protected async addToQueue(siteId: string, fileId: string, url: string, priority: number, revision: number,
-            filePath: string, onProgress?: (event: any) => any, options: any = {}, link?: any): Promise<any> {
+            timemodified: number, filePath: string, onProgress?: (event: any) => any, options: any = {}, link?: any): Promise<any> {
+        await this.dbReady;
+
         this.logger.debug(`Adding ${fileId} to the queue`);
 
-        return this.appDB.insertRecord(this.QUEUE_TABLE, {
+        await this.appDB.insertRecord(this.QUEUE_TABLE, {
             siteId: siteId,
             fileId: fileId,
             url: url,
@@ -583,13 +592,13 @@ export class CoreFilepoolProvider {
             repositorytype: options.repositorytype,
             links: JSON.stringify(link ? [link] : []),
             added: Date.now()
-        }).then(() => {
+        });
+
         // Check if the queue is running.
         this.checkQueueProcessing();
         this.notifyFileDownloading(siteId, fileId);
 
         return this.getQueuePromise(siteId, fileId, true, onProgress);
-        });
     }
 
     /**
@@ -608,9 +617,11 @@ export class CoreFilepoolProvider {
      * @param alreadyFixed Whether the URL has already been fixed.
      * @return Resolved on success.
      */
-    addToQueueByUrl(siteId: string, fileUrl: string, component?: string, componentId?: string | number, timemodified: number = 0,
+    async addToQueueByUrl(siteId: string, fileUrl: string, component?: string, componentId?: string | number,
-            filePath?: string, onProgress?: (event: any) => any, priority: number = 0, options: any = {}, revision?: number,
+            timemodified: number = 0, filePath?: string, onProgress?: (event: any) => any, priority: number = 0, options: any = {},
-            alreadyFixed?: boolean): Promise<any> {
+            revision?: number, alreadyFixed?: boolean): Promise<any> {
+        await this.dbReady;
+
         let fileId,
             link,
             queueDeferred;
@@ -2309,16 +2320,17 @@ export class CoreFilepoolProvider {
      * @param fileUrl The file URL.
      * @return Resolved with file object from DB on success, rejected otherwise.
      */
-    protected hasFileInQueue(siteId: string, fileId: string): Promise<CoreFilepoolQueueEntry> {
+    protected async hasFileInQueue(siteId: string, fileId: string): Promise<CoreFilepoolQueueEntry> {
-        return this.appDB.getRecord(this.QUEUE_TABLE, { siteId: siteId, fileId: fileId }).then((entry) => {
+        await this.dbReady;
+
+        const entry = await this.appDB.getRecord(this.QUEUE_TABLE, { siteId: siteId, fileId: fileId });
         if (typeof entry === 'undefined') {
-                return Promise.reject(null);
+            throw null;
         }
         // Convert the links to an object.
         entry.links = this.textUtils.parseJSON(entry.links, []);
 
         return entry;
-        });
     }
 
     /**
@@ -2546,19 +2558,25 @@ export class CoreFilepoolProvider {
      *
      * @return Resolved on success. Rejected on failure.
      */
-    protected processImportantQueueItem(): Promise<any> {
+    protected async processImportantQueueItem(): Promise<any> {
-        return this.appDB.getRecords(this.QUEUE_TABLE, undefined, 'priority DESC, added ASC', undefined, 0, 1).then((items) => {
+        await this.dbReady;
+
+        let items;
+
+        try {
+            items = await this.appDB.getRecords(this.QUEUE_TABLE, undefined, 'priority DESC, added ASC', undefined, 0, 1);
+        } catch (err) {
+            throw this.ERR_QUEUE_IS_EMPTY;
+        }
+
         const item = items.pop();
         if (!item) {
-                return Promise.reject(this.ERR_QUEUE_IS_EMPTY);
+            throw this.ERR_QUEUE_IS_EMPTY;
         }
         // Convert the links to an object.
         item.links = this.textUtils.parseJSON(item.links, []);
 
         return this.processQueueItem(item);
-        }, () => {
-            return Promise.reject(this.ERR_QUEUE_IS_EMPTY);
-        });
     }
 
     /**
@@ -2685,7 +2703,9 @@ export class CoreFilepoolProvider {
      * @param fileId The file ID.
      * @return Resolved on success. Rejected on failure. It is advised to silently ignore failures.
      */
-    protected removeFromQueue(siteId: string, fileId: string): Promise<any> {
+    protected async removeFromQueue(siteId: string, fileId: string): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.deleteRecords(this.QUEUE_TABLE, { siteId: siteId, fileId: fileId });
     }
 
@@ -3003,12 +3023,14 @@ export class CoreFilepoolProvider {
      *
      * @return Promise resolved when done.
      */
-    treatExtensionInQueue(): Promise<any> {
+    async treatExtensionInQueue(): Promise<any> {
+        await this.dbReady;
+
         this.logger.debug('Treat extensions in queue');
 
-        return this.appDB.getAllRecords(this.QUEUE_TABLE).then((entries) => {
+        const entries = await this.appDB.getAllRecords(this.QUEUE_TABLE);
-            const promises = [];
+
-            entries.forEach((entry) => {
+        return Promise.all(entries.map((entry) => {
 
             // For files in the queue, we only need to remove the extension from the fileId.
             // After downloading, additional info will be added.
@@ -3019,11 +3041,8 @@ export class CoreFilepoolProvider {
                 return;
             }
 
-                promises.push(this.appDB.updateRecords(this.QUEUE_TABLE, { fileId: entry.fileId }, { fileId: fileId }));
+            return this.appDB.updateRecords(this.QUEUE_TABLE, { fileId: entry.fileId }, { fileId: fileId });
-            });
+        }));
-
-            return Promise.all(promises);
-        });
     }
 
     /**

src/providers/local-notifications.ts

@@ -17,13 +17,13 @@ import { Platform, Alert, AlertController } from 'ionic-angular';
 import { LocalNotifications, ILocalNotification } from '@ionic-native/local-notifications';
 import { Push } from '@ionic-native/push';
 import { TranslateService } from '@ngx-translate/core';
-import { CoreAppProvider } from './app';
+import { CoreAppProvider, CoreAppSchema } from './app';
 import { CoreConfigProvider } from './config';
 import { CoreEventsProvider } from './events';
 import { CoreLoggerProvider } from './logger';
 import { CoreTextUtilsProvider } from './utils/text';
 import { CoreUtilsProvider } from './utils/utils';
-import { SQLiteDB, SQLiteDBTableSchema } from '@classes/sqlitedb';
+import { SQLiteDB } from '@classes/sqlitedb';
 import { CoreConstants } from '@core/constants';
 import { CoreConfigConstants } from '../configconstants';
 import { Subject, Subscription } from 'rxjs';
@@ -40,7 +40,10 @@ export class CoreLocalNotificationsProvider {
     protected SITES_TABLE = 'notification_sites'; // Store to asigne unique codes to each site.
     protected COMPONENTS_TABLE = 'notification_components'; // Store to asigne unique codes to each component.
     protected TRIGGERED_TABLE = 'notifications_triggered'; // Store to prevent re-triggering notifications.
-    protected tablesSchema: SQLiteDBTableSchema[] = [
+    protected tablesSchema: CoreAppSchema = {
+        name: 'CoreLocalNotificationsProvider',
+        version: 1,
+        tables: [
             {
                 name: this.SITES_TABLE,
                 columns: [
@@ -86,10 +89,12 @@ export class CoreLocalNotificationsProvider {
                     }
                 ]
             }
-    ];
+        ]
+    };
 
     protected logger;
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     protected codes: { [s: string]: number } = {};
     protected codeRequestsQueue = {};
     protected observables = {};
@@ -114,7 +119,9 @@ export class CoreLocalNotificationsProvider {
 
         this.logger = logger.getInstance('CoreLocalNotificationsProvider');
         this.appDB = appProvider.getDB();
-        this.appDB.createTablesFromSchema(this.tablesSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.tablesSchema).catch(() => {
+            // Ignore errors.
+        });
 
         platform.ready().then(() => {
             // Listen to events.
@@ -242,34 +249,35 @@ export class CoreLocalNotificationsProvider {
      * @param id ID of the element to get its code.
      * @return Promise resolved when the code is retrieved.
      */
-    protected getCode(table: string, id: string): Promise<number> {
+    protected async getCode(table: string, id: string): Promise<number> {
+        await this.dbReady;
+
         const key = table + '#' + id;
 
         // Check if the code is already in memory.
         if (typeof this.codes[key] != 'undefined') {
-            return Promise.resolve(this.codes[key]);
+            return this.codes[key];
         }
 
+        try {
             // Check if we already have a code stored for that ID.
-        return this.appDB.getRecord(table, { id: id }).then((entry) => {
+            const entry = await this.appDB.getRecord(table, { id: id });
             this.codes[key] = entry.code;
 
             return entry.code;
-        }).catch(() => {
+        } catch (err) {
             // No code stored for that ID. Create a new code for it.
-            return this.appDB.getRecords(table, undefined, 'code DESC').then((entries) => {
+            const entries = await this.appDB.getRecords(table, undefined, 'code DESC');
             let newCode = 0;
             if (entries.length > 0) {
                 newCode = entries[0].code + 1;
             }
 
-                return this.appDB.insertRecord(table, { id: id, code: newCode }).then(() => {
+            await this.appDB.insertRecord(table, { id: id, code: newCode });
             this.codes[key] = newCode;
 
             return newCode;
-                });
+        }
-            });
-        });
     }
 
     /**
@@ -352,8 +360,11 @@ export class CoreLocalNotificationsProvider {
      * @param notification Notification to check.
      * @return Promise resolved with a boolean indicating if promise is triggered (true) or not.
      */
-    isTriggered(notification: ILocalNotification): Promise<any> {
+    async isTriggered(notification: ILocalNotification): Promise<boolean> {
-        return this.appDB.getRecord(this.TRIGGERED_TABLE, { id: notification.id }).then((stored) => {
+        await this.dbReady;
+
+        try {
+            const stored = await this.appDB.getRecord(this.TRIGGERED_TABLE, { id: notification.id });
             let triggered = (notification.trigger && notification.trigger.at) || 0;
 
             if (typeof triggered != 'number') {
@@ -361,9 +372,9 @@ export class CoreLocalNotificationsProvider {
             }
 
             return stored.at === triggered;
-        }).catch(() => {
+        } catch (err) {
             return this.localNotifications.isTriggered(notification.id);
-        });
+        }
     }
 
     /**
@@ -477,7 +488,9 @@ export class CoreLocalNotificationsProvider {
      * @param id Notification ID.
      * @return Promise resolved when it is removed.
      */
-    removeTriggered(id: number): Promise<any> {
+    async removeTriggered(id: number): Promise<any> {
+        await this.dbReady;
+
         return this.appDB.deleteRecords(this.TRIGGERED_TABLE, { id: id });
     }
 
@@ -714,7 +727,9 @@ export class CoreLocalNotificationsProvider {
      * @param notification Triggered notification.
      * @return Promise resolved when stored, rejected otherwise.
      */
-    trigger(notification: ILocalNotification): Promise<any> {
+    async trigger(notification: ILocalNotification): Promise<any> {
+        await this.dbReady;
+
         const entry = {
             id: notification.id,
             at: notification.trigger && notification.trigger.at ? notification.trigger.at : Date.now()
@@ -730,7 +745,9 @@ export class CoreLocalNotificationsProvider {
      * @param newName The new name.
      * @return Promise resolved when done.
      */
-    updateComponentName(oldName: string, newName: string): Promise<any> {
+    async updateComponentName(oldName: string, newName: string): Promise<any> {
+        await this.dbReady;
+
         const oldId = this.COMPONENTS_TABLE + '#' + oldName,
             newId = this.COMPONENTS_TABLE + '#' + newName;
 

src/providers/sites.ts

@@ -15,7 +15,7 @@
 import { Injectable, Injector } from '@angular/core';
 import { HttpClient } from '@angular/common/http';
 import { TranslateService } from '@ngx-translate/core';
-import { CoreAppProvider } from './app';
+import { CoreAppProvider, CoreAppSchema } from './app';
 import { CoreEventsProvider } from './events';
 import { CoreLoggerProvider } from './logger';
 import { CoreSitesFactoryProvider } from './sites-factory';
@@ -170,7 +170,7 @@ export const enum CoreSitesReadingStrategy {
  * their own database tables. Example:
  *
  * constructor(sitesProvider: CoreSitesProvider) {
- *     this.sitesProvider.createTableFromSchema(this.tableSchema);
+ *     this.sitesProvider.registerSiteSchema(this.siteSchema);
  *
  * This provider will automatically create the tables in the databases of all the instantiated sites, and also to the
  * databases of sites instantiated from now on.
@@ -181,7 +181,10 @@ export class CoreSitesProvider {
     protected SITES_TABLE = 'sites';
     protected CURRENT_SITE_TABLE = 'current_site';
     protected SCHEMA_VERSIONS_TABLE = 'schema_versions';
-    protected appTablesSchema: SQLiteDBTableSchema[] = [
+    protected appTablesSchema: CoreAppSchema = {
+        name: 'CoreSitesProvider',
+        version: 1,
+        tables: [
             {
                 name: this.SITES_TABLE,
                 columns: [
@@ -233,7 +236,8 @@ export class CoreSitesProvider {
                     }
                 ]
             }
-    ];
+        ]
+    };
 
     // Constants to validate a site version.
     protected WORKPLACE_APP = 3;
@@ -249,6 +253,7 @@ export class CoreSitesProvider {
     protected currentSite: CoreSite;
     protected sites: { [s: string]: CoreSite } = {};
     protected appDB: SQLiteDB;
+    protected dbReady: Promise<any>; // Promise resolved when the app DB is initialized.
     protected siteSchemasMigration: { [siteId: string]: Promise<any> } = {};
 
     // Schemas for site tables. Other providers can add schemas in here.
@@ -323,7 +328,9 @@ export class CoreSitesProvider {
         this.logger = logger.getInstance('CoreSitesProvider');
 
         this.appDB = appProvider.getDB();
-        this.appDB.createTablesFromSchema(this.appTablesSchema);
+        this.dbReady = appProvider.createTablesFromSchema(this.appTablesSchema).catch(() => {
+            // Ignore errors.
+        });
         this.registerSiteSchema(this.siteSchema);
     }
 
@@ -859,7 +866,9 @@ export class CoreSitesProvider {
      * @param config Site config (from tool_mobile_get_config).
      * @return Promise resolved when done.
      */
-    addSite(id: string, siteUrl: string, token: string, info: any, privateToken: string = '', config?: any): Promise<any> {
+    async addSite(id: string, siteUrl: string, token: string, info: any, privateToken: string = '', config?: any): Promise<any> {
+        await this.dbReady;
+
         const entry = {
             id: id,
             siteUrl: siteUrl,
@@ -1070,29 +1079,32 @@ export class CoreSitesProvider {
      * @param siteId ID of the site to delete.
      * @return Promise to be resolved when the site is deleted.
      */
-    deleteSite(siteId: string): Promise<any> {
+    async deleteSite(siteId: string): Promise<void> {
+        await this.dbReady;
+
         this.logger.debug(`Delete site ${siteId}`);
 
         if (typeof this.currentSite != 'undefined' && this.currentSite.id == siteId) {
             this.logout();
         }
 
-        return this.getSite(siteId).then((site: CoreSite) => {
+        const site = await this.getSite(siteId);
-            return site.deleteDB().then(() => {
+
+        await site.deleteDB();
+
         // Site DB deleted, now delete the app from the list of sites.
         delete this.sites[siteId];
 
-                return this.appDB.deleteRecords(this.SITES_TABLE, { id: siteId }).then(() => {
+        try {
-                    // Site deleted from sites list, now delete the folder.
+            await this.appDB.deleteRecords(this.SITES_TABLE, { id: siteId });
-                    return site.deleteFolder();
+        } catch (err) {
-                }, () => {
             // DB remove shouldn't fail, but we'll go ahead even if it does.
-                    return site.deleteFolder();
+        }
-                }).then(() => {
+
+        // Site deleted from sites list, now delete the folder.
+        await site.deleteFolder();
+
         this.eventsProvider.trigger(CoreEventsProvider.SITE_DELETED, site, siteId);
-                });
-            });
-        });
     }
 
     /**
@@ -1100,10 +1112,12 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved with true if there are sites and false if there aren't.
      */
-    hasSites(): Promise<boolean> {
+    async hasSites(): Promise<boolean> {
-        return this.appDB.countRecords(this.SITES_TABLE).then((count) => {
+        await this.dbReady;
+
+        const count = await this.appDB.countRecords(this.SITES_TABLE);
+
         return count > 0;
-        });
     }
 
     /**
@@ -1112,18 +1126,24 @@ export class CoreSitesProvider {
      * @param siteId The site ID. If not defined, current site (if available).
      * @return Promise resolved with the site.
      */
-    getSite(siteId?: string): Promise<CoreSite> {
+    async getSite(siteId?: string): Promise<CoreSite> {
+        await this.dbReady;
+
         if (!siteId) {
-            return this.currentSite ? Promise.resolve(this.currentSite) : Promise.reject(null);
+            if (this.currentSite) {
+                return this.currentSite;
+            }
+
+            throw null;
         } else if (this.currentSite && this.currentSite.getId() == siteId) {
-            return Promise.resolve(this.currentSite);
+            return this.currentSite;
         } else if (typeof this.sites[siteId] != 'undefined') {
-            return Promise.resolve(this.sites[siteId]);
+            return this.sites[siteId];
         } else {
             // Retrieve and create the site.
-            return this.appDB.getRecord(this.SITES_TABLE, { id: siteId }).then((data) => {
+            const data = await this.appDB.getRecord(this.SITES_TABLE, { id: siteId });
+
             return this.makeSiteFromSiteListEntry(data);
-            });
         }
     }
 
@@ -1199,8 +1219,11 @@ export class CoreSitesProvider {
      * @param ids IDs of the sites to get. If not defined, return all sites.
      * @return Promise resolved when the sites are retrieved.
      */
-    getSites(ids?: string[]): Promise<CoreSiteBasicInfo[]> {
+    async getSites(ids?: string[]): Promise<CoreSiteBasicInfo[]> {
-        return this.appDB.getAllRecords(this.SITES_TABLE).then((sites) => {
+        await this.dbReady;
+
+        const sites = await this.appDB.getAllRecords(this.SITES_TABLE);
+
         const formattedSites = [];
         sites.forEach((site) => {
             if (!ids || ids.indexOf(site.id) > -1) {
@@ -1219,7 +1242,6 @@ export class CoreSitesProvider {
         });
 
         return formattedSites;
-        });
     }
 
     /**
@@ -1257,12 +1279,14 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved when the sites IDs are retrieved.
      */
-    getLoggedInSitesIds(): Promise<string[]> {
+    async getLoggedInSitesIds(): Promise<string[]> {
-        return this.appDB.getRecords(this.SITES_TABLE, {loggedOut : 0}).then((sites) => {
+        await this.dbReady;
+
+        const sites = await this.appDB.getRecords(this.SITES_TABLE, {loggedOut : 0});
+
         return sites.map((site) => {
             return site.id;
         });
-        });
     }
 
     /**
@@ -1270,12 +1294,14 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved when the sites IDs are retrieved.
      */
-    getSitesIds(): Promise<string[]> {
+    async getSitesIds(): Promise<string[]> {
-        return this.appDB.getAllRecords(this.SITES_TABLE).then((sites) => {
+        await this.dbReady;
+
+        const sites = await this.appDB.getAllRecords(this.SITES_TABLE);
+
         return sites.map((site) => {
             return site.id;
         });
-        });
     }
 
     /**
@@ -1284,15 +1310,17 @@ export class CoreSitesProvider {
      * @param siteid ID of the site the user is accessing.
      * @return Promise resolved when current site is stored.
      */
-    login(siteId: string): Promise<void> {
+    async login(siteId: string): Promise<void> {
+        await this.dbReady;
+
         const entry = {
             id: 1,
             siteId: siteId
         };
 
-        return this.appDB.insertRecord(this.CURRENT_SITE_TABLE, entry).then(() => {
+        await this.appDB.insertRecord(this.CURRENT_SITE_TABLE, entry);
+
         this.eventsProvider.trigger(CoreEventsProvider.LOGIN, {}, siteId);
-        });
     }
 
     /**
@@ -1300,7 +1328,9 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved when the user is logged out.
      */
-    logout(): Promise<any> {
+    async logout(): Promise<void> {
+        await this.dbReady;
+
         let siteId;
         const promises = [];
 
@@ -1317,9 +1347,11 @@ export class CoreSitesProvider {
             promises.push(this.appDB.deleteRecords(this.CURRENT_SITE_TABLE, { id: 1 }));
         }
 
-        return Promise.all(promises).finally(() => {
+        try {
+            await Promise.all(promises);
+        } finally {
             this.eventsProvider.trigger(CoreEventsProvider.LOGOUT, {}, siteId);
-        });
+        }
     }
 
     /**
@@ -1327,21 +1359,24 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved if a session is restored.
      */
-    restoreSession(): Promise<any> {
+    async restoreSession(): Promise<any> {
         if (this.sessionRestored) {
             return Promise.reject(null);
         }
 
+        await this.dbReady;
+
         this.sessionRestored = true;
 
-        return this.appDB.getRecord(this.CURRENT_SITE_TABLE, { id: 1 }).then((currentSite) => {
+        try {
+            const currentSite = await this.appDB.getRecord(this.CURRENT_SITE_TABLE, { id: 1 });
             const siteId = currentSite.siteId;
             this.logger.debug(`Restore session in site ${siteId}`);
 
             return this.loadSite(siteId);
-        }).catch(() => {
+        } catch (err) {
             // No current session.
-        });
+        }
     }
 
     /**
@@ -1351,8 +1386,10 @@ export class CoreSitesProvider {
      * @param loggedOut True to set the site as logged out, false otherwise.
      * @return Promise resolved when done.
      */
-    setSiteLoggedOut(siteId: string, loggedOut: boolean): Promise<any> {
+    async setSiteLoggedOut(siteId: string, loggedOut: boolean): Promise<any> {
-        return this.getSite(siteId).then((site) => {
+        await this.dbReady;
+
+        const site = await this.getSite(siteId);
         const newValues = {
             token: '', // Erase the token for security.
             loggedOut: loggedOut ? 1 : 0
@@ -1361,7 +1398,6 @@ export class CoreSitesProvider {
         site.setLoggedOut(loggedOut);
 
         return this.appDB.updateRecords(this.SITES_TABLE, newValues, { id: siteId });
-        });
     }
 
     /**
@@ -1396,8 +1432,10 @@ export class CoreSitesProvider {
      * @param privateToken User's private token.
      * @return A promise resolved when the site is updated.
      */
-    updateSiteTokenBySiteId(siteId: string, token: string, privateToken: string = ''): Promise<any> {
+    async updateSiteTokenBySiteId(siteId: string, token: string, privateToken: string = ''): Promise<any> {
-        return this.getSite(siteId).then((site) => {
+        await this.dbReady;
+
+        const site = await this.getSite(siteId);
         const newValues = {
             token: token,
             privateToken: privateToken,
@@ -1409,7 +1447,6 @@ export class CoreSitesProvider {
         site.setLoggedOut(false); // Token updated means the user authenticated again, not logged out anymore.
 
         return this.appDB.updateRecords(this.SITES_TABLE, newValues, { id: siteId });
-        });
     }
 
     /**
@@ -1418,9 +1455,14 @@ export class CoreSitesProvider {
      * @param siteid Site's ID.
      * @return A promise resolved when the site is updated.
      */
-    updateSiteInfo(siteId: string): Promise<any> {
+    async updateSiteInfo(siteId: string): Promise<any> {
-        return this.getSite(siteId).then((site) => {
+        await this.dbReady;
-            return site.fetchSiteInfo().then((info) => {
+
+        const site = await this.getSite(siteId);
+
+        try {
+
+            const info = await site.fetchSiteInfo();
             site.setInfo(info);
 
             const versionCheck = this.isValidMoodleVersion(info);
@@ -1430,9 +1472,14 @@ export class CoreSitesProvider {
             }
 
             // Try to get the site config.
-                return this.getSiteConfig(site).catch(() => {
+            let config;
+
+            try {
+                config = await this.getSiteConfig(site);
+            } catch (error) {
                 // Error getting config, keep the current one.
-                }).then((config) => {
+            }
+
             const newValues: any = {
                 info: JSON.stringify(info),
                 loggedOut: site.isLoggedOut() ? 1 : 0
@@ -1443,14 +1490,14 @@ export class CoreSitesProvider {
                 newValues.config = JSON.stringify(config);
             }
 
-                    return this.appDB.updateRecords(this.SITES_TABLE, newValues, { id: siteId }).finally(() => {
+            try {
+                await this.appDB.updateRecords(this.SITES_TABLE, newValues, { id: siteId });
+            } finally {
                 this.eventsProvider.trigger(CoreEventsProvider.SITE_UPDATED, info, siteId);
-                    });
+            }
-                });
+        } catch (error) {
-            }).catch((error) => {
             // Ignore that we cannot fetch site info. Probably the auth token is invalid.
-            });
+        }
-        });
     }
 
     /**
@@ -1476,11 +1523,13 @@ export class CoreSitesProvider {
      * @param username If set, it will return only the sites where the current user has this username.
      * @return Promise resolved with the site IDs (array).
      */
-    getSiteIdsFromUrl(url: string, prioritize?: boolean, username?: string): Promise<string[]> {
+    async getSiteIdsFromUrl(url: string, prioritize?: boolean, username?: string): Promise<string[]> {
+        await this.dbReady;
+
         // If prioritize is true, check current site first.
         if (prioritize && this.currentSite && this.currentSite.containsUrl(url)) {
             if (!username || this.currentSite.getInfo().username == username) {
-                return Promise.resolve([this.currentSite.getId()]);
+                return [this.currentSite.getId()];
             }
         }
 
@@ -1489,18 +1538,19 @@ export class CoreSitesProvider {
             // URL doesn't have http(s) protocol. Check if it has any protocol.
             if (this.urlUtils.isAbsoluteURL(url)) {
                 // It has some protocol. Return empty array.
-                return Promise.resolve([]);
+                return [];
             } else {
                 // No protocol, probably a relative URL. Return current site.
                 if (this.currentSite) {
-                    return Promise.resolve([this.currentSite.getId()]);
+                    return [this.currentSite.getId()];
                 } else {
-                    return Promise.resolve([]);
+                    return [];
                 }
             }
         }
 
-        return this.appDB.getAllRecords(this.SITES_TABLE).then((siteEntries) => {
+        try {
+            const siteEntries = await this.appDB.getAllRecords(this.SITES_TABLE);
             const ids = [];
             const promises = [];
 
@@ -1516,13 +1566,13 @@ export class CoreSitesProvider {
                 }
             });
 
-            return Promise.all(promises).then(() => {
+            await Promise.all(promises);
+
             return ids;
-            });
+        } catch (error) {
-        }).catch(() => {
             // Shouldn't happen.
             return [];
-        });
+        }
     }
 
     /**
@@ -1530,10 +1580,12 @@ export class CoreSitesProvider {
      *
      * @return Promise resolved with the site ID.
      */
-    getStoredCurrentSiteId(): Promise<string> {
+    async getStoredCurrentSiteId(): Promise<string> {
-        return this.appDB.getRecord(this.CURRENT_SITE_TABLE, { id: 1 }).then((currentSite) => {
+        await this.dbReady;
+
+        const currentSite = await this.appDB.getRecord(this.CURRENT_SITE_TABLE, { id: 1 });
+
         return currentSite.siteId;
-        });
     }
 
     /**
@@ -1580,6 +1632,7 @@ export class CoreSitesProvider {
      * Create a table in all the sites databases.
      *
      * @param table Table schema.
+     * @deprecated. Please use registerSiteSchema instead.
      */
     createTableFromSchema(table: SQLiteDBTableSchema): void {
         this.createTablesFromSchema([table]);
@@ -1589,6 +1642,7 @@ export class CoreSitesProvider {
      * Create several tables in all the sites databases.
      *
      * @param tables List of tables schema.
+     * @deprecated. Please use registerSiteSchema instead.
      */
     createTablesFromSchema(tables: SQLiteDBTableSchema[]): void {
         // Add the tables to the list of schemas. This list is to create all the tables in new sites.