Generalized HTTP handling for TypeScript

entry.ts

/* eslint-disable max-classes-per-file */

/*
 * An experiment about how we can structure this codebase
 */

/*
 * Request handling infrastructure
 */

import { APIGatewayProxyEvent, APIGatewayProxyHandler, APIGatewayProxyResult } from './Infrastructure/Aws/APIGatewayHandler';

class Request {
    public static fromAPIGatewayProxyEvent(event: APIGatewayProxyEvent): Request {
        return new Request();
    }
}

class Response {
    public static fromAPIGatewayProxyResult(result: APIGatewayProxyResult): Response {
        return new Response();
    }

    public toAPIGatewayProxyResult(): APIGatewayProxyResult {
        return { statusCode: 500, body: '' };
    }
}

type RequestHandler = (request: Request) => Promise<Response>;

class LambdaHandler {
    public handle(handler: RequestHandler): APIGatewayProxyHandler {
        return (async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> =>
            handler(Request.fromAPIGatewayProxyEvent(event))
                .then((result) => result.toAPIGatewayProxyResult()));
    }
}

/*
 * Controllers, defined/constructed in App.ts
 */

class EndpointController {
    public async handle(request: Request): Promise<Response> {
        console.log('request', request);
        return new Response();
    }
}

/*
 * The actual entry file
 */

const handler = new LambdaHandler(); // we can add middleware if we want

const endpoint = handler.handle(async (request) => new EndpointController().handle(request));

export {
    endpoint,
};