restify-aws-lambda

Introduction

This project describes a way to implement aws lambda functions in form of enterprise patterns as a multi tier application and uses dynamodb local and lambda local to simplify the local implementation. The project seperate the application into three layers. The controllers, the services and the repository (DAO layer)

The project is based on TypeScript and uses the reflect-metadata library to map the AWS lambda event to the respective controllers.

How to get start?

You can look at the "book-store" example which is in the src / domains. There you can see how an application could look like. In src / index.ts you will find an awsHandler and how to register a controller.

sh npm install

sh npm run build

Testing

Run all test
npm run test

The component tests are testing all Layers (Controller, Service and Repository). These tests build a local dynamodb on the fly and create the appropriate table you need. You can insert, select and update data in the table.

Create your Controller

When you create a new controller you need first to define the resource that match to the aws event

example aws event:

{
  "resource": "/bookstores",
  "path": "/bookstores",
  "httpMethod": "GET",
  "headers": {},
  "queryStringParameters": null,
  "pathParameters": null,
  "requestContext":
  {
    "path": "/bookstores",
    "accountId": "",
    "resourceId": "",
    "stage": "",
    "requestId": "",
    "resourcePath": "/",
    "httpMethod": "GET",
    "apiId": ""
  },
  "body": null,
  "isBase64Encoded": false
}

As you can see, the resource in this example is "/bookstores", that means your controller need to defined by the same resource: @Controller('/bookstores'). See following code:

Example Controller:

@Singleton
@Model(BookStore)
@Controller('/bookstores')
export default class BookStoreController implements IBookStoreController   {
    @Inject
    private bookStoreService: BookStoreService;
 
    @GET()
    public getBookStores(): Promise<IBookStore[]> {
      return this.bookStoreService.getBookStores();
    }
 
    @GET('/{id}')
    public getBookStoreById(@PathParam('id') id: string): Promise<IBookStore> {
      Validator.validateField('id', id, Validator.VALIDATOR_SCHEMA.UUID_REQUIRED);
      return this.bookStoreService.getBookStoreById(id);
    }
 
    @POST()
    public createBookStore (bookStore: IBookStore): Promise<IBookStore> {
      return this.bookStoreService.createBookStore(bookStore);
    }
    ....
}

As you can also see, you can use annotations (as in jax-rs or spring requestMapping) @GET, @POST, @PUT, @DELETE to define the routing. In addition, you can use @PathParam and @QueryParam to access the path paremeter and query paremeter

Adding new Controller in the index.ts:

ControllerRegistry.register(BookStoreController);

Thats it!

By simply registering the controllers, you no longer need to worry about mapping the aws event for the particular component, and your code remains clearly structured

Available Modules/Components

import { Model, Controller, POST, GET, PUT, PathParam, DELETE 
 ControllerRegistry, Response, QueryParam, MethodNotFoundError, NotFoundError
 ValidationError, execute, Validator, Model} from 'restify-aws-lambda';

You can import following exported methods/classes/modules like below:

components	description
ControllerRegistry	to register a controller
Controller	@Controller to define an new controller
GET	HTTP GET -> @GET
POST	HTTP POST -> @POST
PUT	HTTP PUT -> @PUT
DELETE	HTTP DELETE -> @DELETE
PathParam	@PathParam to get the path paramenter
QueryParam	@QueryParam to get the query paremeter
execute	execute the incoming aws event
Model	Model for example Book Store

Please take a look of the example how you can use the below components.