targety

🎯 Targety

A TypeScript based focus build library for Routing on AWS Lambda.

Features

• Focus on Decorators
• CORS
• Validation (using: Class Validator)
• API Gateway Focus
• Middleware system
• Extensible using middleware and custom decorators
• Defaults (But customizable)
  • Error Handling
  • Responses
• Metadata support for request scoped data passing
• Support for {proxy+}, proxy resources
  • Works with path parameters as it would normally

Installation

Npm:

npm install targety

Yarn:

yarn add targety

Getting Started

The quickest way to get started with Targety is by creating an EntryPoint and Handler.

Example Handler

import {
    Get,
    Handler,
    Middleware,
    Request,
    Response,
    ResponseBody
} from "targety";

export class ExampleHandler extends Handler {
    protected middleware: Middleware[];

    @Get("/test")
    public async getTestMethod(request: Request): Promise<ResponseBody> {
        return Response.ok(request).send({ test: "ok" });
    }
}

The above example is the most basic implementation of a Handler (Router) with Targety. For a more detailed implementation check the examples.

Example EntryPoint

import { Handler, LambdaEntryPoint } from "targety";
import { ExampleHandler } from "./Handler";

class ExampleEntryPoint extends LambdaEntryPoint {
    protected async initializeHandler(): Promise<Handler> {
        return new ExampleHandler();
    }
}

const entryPoint = new ExampleEntryPoint();

// The exposed handler
export const handler = entryPoint.handle.bind(entryPoint);

The EntryPoint should create and expose the Handler. The general idea for the entry point, is to allow you to setup services, connections, configuration, ... once that is then passed to the constructor of the handler.

For a complete example see examples.

Gotchas

This is a list of hidden defaults and functionalities in the library that are good to know.

Default Error Handling

Whenever an error is throw that is "known" aka. a error available in the library errors this error will be mapped to the HTTP Status Code that it belongs too.

This is only when an error is thrown from a Handler class, for instance when a route fails. When an error is unknown and thrown this is returned as an internal server error, the logs will reflect this.

For instance throwing a error:

import { Error } from "targety";

// <snip>
    throw new Error.UnauthorizedError("Unauthorized");
// </snip>

Will result in the error response by default as handeld in the Handler:

{
    "message": "Unauthorized",
    "errorCode": "Unauthorized",
    "awsRequestId": "f9d04c1c-794f-44af-aeb0-65c6ef907ff1"
}

The AWS Request Id is the actual AWS Request Id that you could use for finding the corresponding logs.

Default Cors Headers

Every response will get a set of Default Headers these can be overwritten and are defined in the library here

AWS Request ID Header

By default the AWS Request ID is returned as a header X-AWS-Request-Id

Default Logging

The library does use pino for it's logging capabilities, this will be configurable in a later version. To enable logging export the environment variable LOG_LEVEL.

Further Reading

Other interesting and relevant links.

Docs

Docs for the latest build can be found here:

• API Docs
• Written Docs

Written docs contain additional details on usage, examples, ...

Example

The project contains an example in the examples directory. This is a working example that can be deployed on AWS if desired.

More examples might be added to further explain functionality.

Class Validation

The build in class validation is just a wrapper around class-validator I recommend checking out there documentation.

WIP

• API Gateway Proxy Support (/{proxy+})
• More configuration options
• Make the docs available as a Page
• Make the logging module configurable