Vmeda.Online/src/core/classes/database/database-table-proxy.ts
2022-03-14 13:10:48 +01:00

285 lines
8.7 KiB
TypeScript

// (C) Copyright 2015 Moodle Pty Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import { CoreConstants } from '@/core/constants';
import { asyncInstance } from '@/core/utils/async-instance';
import { SQLiteDBRecordValues } from '@classes/sqlitedb';
import { CoreConfig, CoreConfigProvider } from '@services/config';
import { CoreEventObserver, CoreEvents } from '@singletons/events';
import {
CoreDatabaseConfiguration,
CoreDatabaseReducer,
CoreDatabaseTable,
CoreDatabaseConditions,
GetDBRecordPrimaryKey,
CoreDatabaseQueryOptions,
CoreDatabaseTableConstructor,
} from './database-table';
import { CoreDebugDatabaseTable } from './debug-database-table';
import { CoreEagerDatabaseTable } from './eager-database-table';
import { CoreLazyDatabaseTable } from './lazy-database-table';
/**
* Database table proxy used to route database interactions through different implementations.
*
* This class allows using a database wrapper with different optimization strategies that can be changed at runtime.
*/
export class CoreDatabaseTableProxy<
DBRecord extends SQLiteDBRecordValues = SQLiteDBRecordValues,
PrimaryKeyColumn extends keyof DBRecord = 'id',
PrimaryKey extends GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn> = GetDBRecordPrimaryKey<DBRecord, PrimaryKeyColumn>
> extends CoreDatabaseTable<DBRecord, PrimaryKeyColumn, PrimaryKey> {
protected readonly DEFAULT_CACHING_STRATEGY = CoreDatabaseCachingStrategy.None;
protected target = asyncInstance<CoreDatabaseTable<DBRecord, PrimaryKeyColumn>>();
protected environmentObserver?: CoreEventObserver;
protected targetConstructors: Record<
CoreDatabaseCachingStrategy,
CoreDatabaseTableConstructor<DBRecord, PrimaryKeyColumn, PrimaryKey>
> = {
[CoreDatabaseCachingStrategy.Eager]: CoreEagerDatabaseTable,
[CoreDatabaseCachingStrategy.Lazy]: CoreLazyDatabaseTable,
[CoreDatabaseCachingStrategy.None]: CoreDatabaseTable,
};
/**
* @inheritdoc
*/
async initialize(): Promise<void> {
await super.initialize();
this.environmentObserver = CoreEvents.on(CoreConfigProvider.ENVIRONMENT_UPDATED, async () => {
if (!(await this.shouldUpdateTarget())) {
return;
}
this.updateTarget();
});
await this.updateTarget();
}
/**
* @inheritdoc
*/
async destroy(): Promise<void> {
await super.destroy();
this.environmentObserver?.off();
}
/**
* @inheritdoc
*/
matchesConfig(config: Partial<CoreDatabaseConfiguration>): boolean {
const thisDebug = this.config.debug ?? false;
const thisCachingStrategy = this.config.cachingStrategy ?? this.DEFAULT_CACHING_STRATEGY;
const otherDebug = config.debug ?? false;
const otherCachingStrategy = config.cachingStrategy ?? this.DEFAULT_CACHING_STRATEGY;
return super.matchesConfig(config) && thisDebug === otherDebug && thisCachingStrategy === otherCachingStrategy;
}
/**
* @inheritdoc
*/
async getMany(conditions?: Partial<DBRecord>, options?: Partial<CoreDatabaseQueryOptions<DBRecord>>): Promise<DBRecord[]> {
return this.target.getMany(conditions, options);
}
/**
* @inheritdoc
*/
getManyWhere(conditions: CoreDatabaseConditions<DBRecord>): Promise<DBRecord[]> {
return this.target.getManyWhere(conditions);
}
/**
* @inheritdoc
*/
async getOne(
conditions?: Partial<DBRecord>,
options?: Partial<Omit<CoreDatabaseQueryOptions<DBRecord>, 'offset' | 'limit'>>,
): Promise<DBRecord> {
return this.target.getOne(conditions, options);
}
/**
* @inheritdoc
*/
async getOneByPrimaryKey(primaryKey: PrimaryKey): Promise<DBRecord> {
return this.target.getOneByPrimaryKey(primaryKey);
}
/**
* @inheritdoc
*/
async reduce<T>(reducer: CoreDatabaseReducer<DBRecord, T>, conditions?: CoreDatabaseConditions<DBRecord>): Promise<T> {
return this.target.reduce<T>(reducer, conditions);
}
/**
* @inheritdoc
*/
hasAny(conditions?: Partial<DBRecord>): Promise<boolean> {
return this.target.hasAny(conditions);
}
/**
* @inheritdoc
*/
hasAnyByPrimaryKey(primaryKey: PrimaryKey): Promise<boolean> {
return this.target.hasAnyByPrimaryKey(primaryKey);
}
/**
* @inheritdoc
*/
count(conditions?: Partial<DBRecord>): Promise<number> {
return this.target.count(conditions);
}
/**
* @inheritdoc
*/
async insert(record: DBRecord): Promise<void> {
return this.target.insert(record);
}
/**
* @inheritdoc
*/
async update(updates: Partial<DBRecord>, conditions?: Partial<DBRecord>): Promise<void> {
return this.target.update(updates, conditions);
}
/**
* @inheritdoc
*/
async updateWhere(updates: Partial<DBRecord>, conditions: CoreDatabaseConditions<DBRecord>): Promise<void> {
return this.target.updateWhere(updates, conditions);
}
/**
* @inheritdoc
*/
async delete(conditions?: Partial<DBRecord>): Promise<void> {
return this.target.delete(conditions);
}
/**
* @inheritdoc
*/
async deleteByPrimaryKey(primaryKey: PrimaryKey): Promise<void> {
return this.target.deleteByPrimaryKey(primaryKey);
}
/**
* Get database configuration to use at runtime.
*
* @returns Database configuration.
*/
protected async getRuntimeConfig(): Promise<Partial<CoreDatabaseConfiguration>> {
await CoreConfig.ready();
return {
...this.config,
...CoreConstants.CONFIG.databaseOptimizations,
...CoreConstants.CONFIG.databaseTableOptimizations?.[this.tableName],
};
}
/**
* Update underlying target instance.
*/
protected async updateTarget(): Promise<void> {
const oldTarget = this.target.instance;
const newTarget = await this.createTarget();
if (oldTarget) {
await oldTarget.destroy();
this.target.resetInstance();
}
await newTarget.initialize();
this.target.setInstance(newTarget);
}
/**
* Check whether the underlying target should be updated.
*
* @returns Whether target should be updated.
*/
protected async shouldUpdateTarget(): Promise<boolean> {
const config = await this.getRuntimeConfig();
const target = await this.target.getInstance();
const originalTarget = target instanceof CoreDebugDatabaseTable ? target.getTarget() : target;
return (config.debug && target === originalTarget)
|| originalTarget?.constructor !== this.targetConstructors[config.cachingStrategy ?? this.DEFAULT_CACHING_STRATEGY]
|| !originalTarget.matchesConfig(config);
}
/**
* Create proxy target.
*
* @returns Target instance.
*/
protected async createTarget(): Promise<CoreDatabaseTable<DBRecord, PrimaryKeyColumn>> {
const config = await this.getRuntimeConfig();
const table = this.createTable(config);
return config.debug ? new CoreDebugDatabaseTable(table) : table;
}
/**
* Create a database table using the given caching strategy.
*
* @param config Database configuration.
* @returns Database table.
*/
protected createTable(config: Partial<CoreDatabaseConfiguration>): CoreDatabaseTable<DBRecord, PrimaryKeyColumn> {
const DatabaseTable = this.targetConstructors[config.cachingStrategy ?? this.DEFAULT_CACHING_STRATEGY];
return new DatabaseTable(config, this.database, this.tableName, this.primaryKeyColumns);
}
}
declare module '@classes/database/database-table' {
/**
* Augment CoreDatabaseConfiguration interface with data specific to this class.
*
* @see https://www.typescriptlang.org/docs/handbook/declaration-merging.html#module-augmentation
*/
export interface CoreDatabaseConfiguration {
cachingStrategy: CoreDatabaseCachingStrategy;
debug: boolean;
}
}
/**
* Database caching strategies.
*/
export enum CoreDatabaseCachingStrategy {
Eager = 'eager',
Lazy = 'lazy',
None = 'none',
}