express-service-bootstrap

<title>license: Apache-2.0</title> license license Apache-2.0 Apache-2.0

This is a convenience package for starting a express based API server with

1. General API Security - (helmet based)
2. Health checks - K8S Health Probes
3. Process exits listeners - Your API server should shutdown as gracefully as possible when it receives any shutdown signals from OS.
4. Include your API documentation - Swagger UI express.
5. Singleton DI container - possibly the best pattern to follow, yet completely flexible and ignorable.
6. Creator pattern - don't use new keyword, this helps in writing better unit tests and mockable classes and features.

Getting Started

1. Please find example code usage in examples folder

import { ApplicationBuilder, ApplicationStartupStatus, ApplicationTypes, Convenience } from "../../dist/src/index.js";
import * as OpenApiDefinition from "./api-def.json" with { type: "json" };

const applicationName = "Test Simple App";
const app = new ApplicationBuilder(applicationName, OpenApiDefinition);
const utilities = new Convenience();

function shouldCompress(req, res) {
    if (req.headers['x-no-compression']) {
        // don't compress responses with this request header
        return false
    }

    // fallback to standard filter function
    return true
}

async function AppStartUp(rootRouter, DIContainer, application) {

    //Connect to DB or create DB Pool
    //Apply Migrations
    //Register Routes,Middleware,etc
    DIContainer.registerInstance("msg", { message: "Hello from DI" }); //Simulate things stored in DI container

    rootRouter
        .get("/", (req, res) => {
            res.send(req.DIProp.fetchInstance("msg").message);
        })
        .post("/", (req, res) => {
            console.log(req.body);
        })
        .get("/error", (req, res) => {
            throw new Error("This is an error to validate final 'ErrorResponseTransformer' error handling of library");
        });

    //Configure your application.
    const apiDocs = utilities.swaggerAPIDocs(OpenApiDefinition);
    application.overrideAppPort(8080)                                                                                            //override the default port 8080(Default 3000)
        .overrideHealthPort(8081)                                                                                                //override the default health port 8081(Default 5678)
        .registerApplicationHandler(utilities.helmetMiddleware(), "*", 1, ApplicationTypes.Both)                                 //register helmet middleware for both application and health
        .registerApplicationHandler(utilities.bodyParserURLEncodingMiddleware(), "*", 2, ApplicationTypes.Main)                  //register body parser url middleware for application
        .registerApplicationHandler(utilities.bodyParserJSONEncodingMiddleware({ limit: '50M' }), "*", 3, ApplicationTypes.Main) //register body parser json middleware for application
        .registerApplicationHandler(apiDocs.router, apiDocs.hostingPath, 4, ApplicationTypes.Main)                               //register api docs
        .registerApplicationHandler(utilities.injectInRequestMiddleware("DIProp", DIContainer), "*", 5, ApplicationTypes.Main) //register DI container middleware
        .registerApplicationHandler(utilities.compressionMiddleware({ filter: shouldCompress }), "*", 6, ApplicationTypes.Main)  //register compression middleware
        .registerApplicationHandler(utilities.staticMiddleware("examples\\simple-express\\public"), "/public", 7, ApplicationTypes.Main)                  //register static file serving middleware
        .overrideCatchAllErrorResponseTransformer((req, error) => ({                                                             //override the default catch all error response transformer
            path: req.path,
            status: 500,
            body: { message: error.message }
        }))


    return {
        status: ApplicationStartupStatus.UP,            // Indicates startup was successful
        data: { message: "Connected to database" }      // Additional data to be returned(Optional)
    };
}

app.overrideStartupHandler(AppStartUp)
    .start()
    .then(() => console.log(`${applicationName} started successfully.`))
    .catch(console.error);


//*******************************
// You can wait for your application to be called by process exit signal
// OR
// If you are done call the Dispose method to stop the application
// await app[Symbol.asyncDispose](); //stop the application and release all resources
//*******************************

Built with

1. Authors ❤️ for Open Source.

Contributions

1. New ideas/techniques are welcomed.
2. Raise a Pull Request.

License

This project is contribution to public domain and completely free for use, view LICENSE.md file for details.

Change Tracking

Version	Changes
1.0.0	Started using express internal parser for json and url encoding