feature(@nejsts/core) create nest application context feature nestjs#201

Author: kamilmysliwiec

package.json

@@ -86,8 +86,7 @@
       "src/**/*.spec.ts",
       "src/core/adapters/*.ts",
       "src/websockets/adapters/*.ts",
-      "src/core/nest-application.ts",
-      "src/core/nest-factory.ts",
+      "src/core/nest-*.ts",
       "src/common/exceptions/*.ts",
       "src/common/services/logger.service.ts",
       "src/core/errors/exceptions",

src/common/index.ts

@@ -28,6 +28,7 @@ export {
     RpcExceptionFilter,
     WsExceptionFilter,
     NestInterceptor,
+    INestApplicationContext,
 } from './interfaces';
 export * from './services/logger.service';
 export * from './pipes';

src/common/interfaces/index.ts

@@ -8,6 +8,7 @@ export * from './modules/module-metadata.interface';
 export * from './metatype.interface';
 export * from './nest-application.interface';
 export * from './nest-microservice.interface';
+export * from './nest-application-context.interface';
 export * from './modules/on-init.interface';
 export * from './modules/on-destroy.interface';
 export * from './exceptions/exception-filter.interface';

src/common/interfaces/nest-application-context.interface.ts

@@ -0,0 +1,15 @@
+import { Metatype } from './metatype.interface';
+
+export interface INestApplicationContext {
+    /**
+     * Allows you to navigate through the modules tree, for example, to pull out a specific instance from the selected module.
+     * @returns INestApplicationContext
+     */
+    select<T>(module: Metatype<T>): INestApplicationContext;
+
+    /**
+     * Makes possible to retrieve the instance of the component or controller available inside the processed module.
+     * @returns T
+     */
+    get<T>(metatypeOrToken: Metatype<T> | string): T;
+}

src/core/nest-application-context.ts

@@ -0,0 +1,44 @@
+
+import { ModuleTokenFactory } from './injector/module-token-factory';
+import { NestContainer, InstanceWrapper } from './injector/container';
+import { NestModuleMetatype } from '@nestjs/common/interfaces/modules/module-metatype.interface';
+import { Metatype } from '@nestjs/common/interfaces';
+import { isFunction } from '@nestjs/common/utils/shared.utils';
+import { INestApplicationContext } from '@nestjs/common';
+
+export class NestApplicationContext {
+    private readonly moduleTokenFactory = new ModuleTokenFactory();
+
+    constructor(
+        private readonly container: NestContainer,
+        private readonly scope: NestModuleMetatype[],
+        private readonly contextModule) {}
+
+    public select<T>(module: Metatype<T>): INestApplicationContext {
+        const modules = this.container.getModules();
+        const moduleMetatype = this.contextModule.metatype;
+        const scope = this.scope.concat(moduleMetatype);
+
+        const token = this.moduleTokenFactory.create(module as any, scope);
+        const selectedModule = modules.get(token);
+        return selectedModule
+          ? new NestApplicationContext(this.container, scope, selectedModule)
+          : null;
+    }
+
+    public get<T>(metatypeOrToken: Metatype<T> | string): T {
+        return this.findInstanceByPrototypeOrToken<T>(metatypeOrToken);
+    }
+
+    private findInstanceByPrototypeOrToken<T>(metatypeOrToken: Metatype<T> | string) {
+        const dependencies = new Map([
+            ...this.contextModule.components,
+            ...this.contextModule.routes,
+        ]);
+        const name = isFunction(metatypeOrToken) ? (metatypeOrToken as any).name : metatypeOrToken;
+        const instanceWrapper = dependencies.get(name);
+        return instanceWrapper
+          ? (instanceWrapper as InstanceWrapper<any>).instance
+          : null;
+    }
+}

src/core/nest-application.ts

@@ -54,8 +54,8 @@ export class NestApplication implements INestApplication {
     }
 
     public setupParserMiddlewares() {
-      this.express.use(bodyParser.json());
-      this.express.use(bodyParser.urlencoded({ extended: true }));
+        this.express.use(bodyParser.json());
+        this.express.use(bodyParser.urlencoded({ extended: true }));
     }
 
     public async setupModules() {
@@ -82,11 +82,11 @@ export class NestApplication implements INestApplication {
     }
 
     public async setupRouter() {
-      const router = ExpressAdapter.createRouter();
-      await this.setupMiddlewares(router);
+        const router = ExpressAdapter.createRouter();
+        await this.setupMiddlewares(router);
 
-      this.routesResolver.resolve(router);
-      this.express.use(validatePath(this.config.getGlobalPrefix()), router);
+        this.routesResolver.resolve(router);
+        this.express.use(validatePath(this.config.getGlobalPrefix()), router);
     }
 
     public connectMicroservice(config: MicroserviceConfiguration): INestMicroservice {

src/core/nest-factory.ts

@@ -10,9 +10,10 @@ import { NestApplication } from './nest-application';
 import { isFunction } from '@nestjs/common/utils/shared.utils';
 import { MicroserviceConfiguration } from '@nestjs/common/interfaces/microservices/microservice-configuration.interface';
 import { ExpressAdapter } from './adapters/express-adapter';
-import { INestApplication, INestMicroservice } from '@nestjs/common';
+import { INestApplication, INestMicroservice, INestApplicationContext } from '@nestjs/common';
 import { MetadataScanner } from './metadata-scanner';
 import { MicroservicesPackageNotFoundException } from './errors/exceptions/microservices-package-not-found.exception';
+import { NestApplicationContext } from './nest-application-context';
 
 const { NestMicroservice } = optional('@nestjs/microservices/nest-microservice') || {} as any;
 
@@ -27,7 +28,7 @@ export class NestFactoryStatic {
     /**
      * Creates an instance of the NestApplication (returns Promise)
      *
-     * @param  {} module Entry ApplicationModule class
+     * @param  {} module Entry (root) application module class
      * @param  {} express Optional express() server instance
      * @returns an `Promise` of the INestApplication instance
      */
@@ -41,7 +42,7 @@ export class NestFactoryStatic {
     /**
      * Creates an instance of the NestMicroservice (returns Promise)
      *
-     * @param  {} module Entry ApplicationModule class
+     * @param  {} module Entry (root) application module class
      * @param  {MicroserviceConfiguration} config Optional microservice configuration
      * @returns an `Promise` of the INestMicroservice instance
      */
@@ -59,6 +60,22 @@ export class NestFactoryStatic {
         );
     }
 
+    /**
+     * Creates an instance of the NestApplicationContext (returns Promise)
+     *
+     * @param  {} module Entry (root) application module class
+     * @returns an `Promise` of the INestApplicationContext instance
+     */
+    public async createApplicationContext(module): Promise<INestApplicationContext> {
+        await this.initialize(module);
+
+        const modules = this.container.getModules().values();
+        const root = modules.next().value;
+        return this.createNestInstance<INestApplicationContext>(
+            new NestApplicationContext(this.container, [], root),
+        );
+    }
+
     private createNestInstance<T>(instance: T) {
         return this.createProxy(instance);
     }