Application

The App class is the core of an ExpressoTS application, handling server creation and configuration. It allows you to set up middleware and providers during the bootstrapping process and offers lifecycle hooks to run code before, after, and during server shutdown.

App express

AppExpress is the Express.js platform implementation specifically designed for ExpressoTS. It integrates seamlessly with the Express.js ecosystem, providing a robust foundation for building and configuring applications within ExpressoTS.

With full support for Express.js middleware, AppExpress enables developers to efficiently manage application setup, execution, and shutdown processes, all while leveraging the familiar Express.js environment.

Here is the App class extending the AppExpress adapter from the Opinionated template:

app.ts

export class App extends AppExpress {
    private config: AppContainer = this.configContainer([AppModule]);

    protected globalConfiguration(): void | Promise<void> {
        this.setGlobalRoutePrefix("/v1");

        this.initEnvironment("development", {
            env: {
                development: ".env.development",
                production: ".env.production",
            },
        });
    }

    protected configureServices(): void {
        this.Provider.register(Env);

        this.Middleware.addBodyParser();
        this.Middleware.setErrorHandler({ showStackTrace: true });
    }

    protected async postServerInitialization(): Promise<void> {
        if (this.isDevelopment()) {
            this.Provider.get(Env).checkFile(".env.development");
        }
    }

    protected serverShutdown(): void {}
}

• this.Provider: an object containing a register method that allows developers to register internal or external ExpressoTS-compatible providers. This method registers classes in the ExpressoTS container to be part of the dependency injection system, enabling the use of different scopes such as Transient, Scoped, and Singleton.

• this.Middleware: offers a set of out-of-the-box middlewares that can be used to configure your application. See the complete list in the Middleware section

tip

Be sure to explore other functionalities available in the class through this, like setGlobalRoutePrefix(), setEngine(), and more.

Lifecycle hooks

An ExpressoTS application and its components follow a lifecycle managed by the framework. ExpressoTS offers lifecycle hooks that let developers track important events and run specific code within modules, providers, or controllers as these events happen.

The diagram below shows the sequence of key lifecycle events, from application startup to when the Node.js process exits.

Add any service to initialize before the server starts.

protected configureServices(): void | Promise<void> { }

Add any service to run after the server starts.

protected postServerInitialization(): void | Promise<void> { }

Add any service to run after the server shuts down.

protected serverShutdown(): void | Promise<void> { }

Hooks execution order

Method configContainer

The configContainer method is used to configure the application container with the modules that will be used in the application.

Example of configuring the application container.

private config: AppContainer = this.configContainer([AppModule]);

Middleware property

The Middleware property is an instance of the MiddlewareManager class, which provides a set of methods to add middleware to the application.

Example of adding a middleware to the application.

this.Middleware.addBodyParser();

Provider property

The Provider property is an instance of the ProviderManager class, which provides a set of methods to register and get providers in the application.

Example of registering a provider in the application.

this.Provider.register(Env);

Method initEnvironment

The initEnvironment method is used to set the environment variables for the application.

Example of setting environment variables for the application.

this.initEnvironment("development", {
    env: {
        development: ".env.development",
        production: ".env.production",
    },
});

Method isDevelopment

It is a helper method that returns a boolean value indicating whether the application is running in development mode. This method is useful for running specific code only in development environments.

Check if the application is running in development mode.

this.isDevelopment(): boolean

Currently this method is being used in the postServerInitialization method to check if the application is running in development mode. If it is, the Env provider is used to check all environment variables.

Check all environment variables in development mode.

protected postServerInitialization(): void {
    if (this.isDevelopment()) {
        this.Provider.get(Env).checkFile(".env.development");
    }
}

Method set global route prefix

You can set a global prefix for all routes in your application. This is useful when you want to version your APIs.

this.setGlobalRoutePrefix("/v1");

Method get http server

The getHttpServer method is used to get the HTTP server instance.

Example of getting the HTTP server instance.

this.getHttpServer(): http.Server

Method to set the engine

The setEngine method is used to set the engine for the application.

Example of setting the engine for the application.

this.setEngine(RenderEngine.Engine.EJS);

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