Strong API middleware

Strongly typed API middleware. Generic library which can be integrated with any HTTP stack.

Installation

$3

npm install @vladbasin/strong-api-middleware @vladbasin/strong-api-mapping reflect-metadata joi

$3

yarn add @vladbasin/strong-api-middleware @vladbasin/strong-api-mapping reflect-metadata joi

Usage

This is a generic middleware library. You can integrate it with any HTTP stack. Currently the following packages use this library:

- @vladbasin/strong-api-middleware-aws-lambda - complete e2e HTTP pipeline integration for AWS Lambda
- [@vladbasin/strong-api-middleware-express]() - IN PROGRESS - complete e2e HTTP pipeline integration for express server
- @vladbasin/strong-api-client - HTTP client which can use shared models to execute request. Therefore, no need to duplicate mapping & validation logic for API consumers & producers.

$3

1. Import reflect-metadata ONCE in your index file:

``typescript
import 'reflect-metadata';
`

2. Define your model

`typescript
import { body, header, path, query } from '@vladbasin/strong-api-mapping';

export class RequestPayload {
@path()
public userId!: number;

@path({ key: 'userId' })
public id!: number;

@query()
public name!: string;

@query()
public isAdmin!: boolean;

@query({ key: 'lastname' })
public surname!: string;

@query({ parser: String })
public cars!: string[];

@query({ parser: Number })
public cash!: number[];

@body()
public details!: DetailsType;

@header({ key: 'Content-Type' })
public contentType!: string;

@header({ key: 'X-Info', parser: String })
public info!: string[];
}
`

3. Define validation rules with Joi

`typescript
export const RequestPayloadSchema = Joi.object({
surname: Joi.string().min(10),
cars: Joi.array().max(3),
// other rules for field content...
});
`

4. Call handleStrongApiRequest() when you want to process HTTP request

`typescript
handleStrongApiRequest({
// configure request handling
request: {
// define request payload model which will be automapped
payload: {
Model: RequestPayload,
schema: RequestPayloadSchema,
},
provideRaw: () => {
// synchronously or ASYNChronously provide RawApiRequest object (headers, body, query string) based on your HTTP stack
// you can also provide CustomApiRequestDataType values to introduce and feed custom decorators with data
},
handle: ({ payload }) => {
// handle api request
// return ApiResponseType
},
},
// configure response handling
response: {
// process request handling error
processFailure: {
options: {
// output possibly sensitive information (useful for debugging)
allowSensitive: true,
},
// OPTIONAL
responseCreator: (error, options, defaultResponseCreator) => {
// create ApiResponseType when error happens (by default done by this library automatically)
},
},
},
});
`

This method returns RawApiResponseType which you can later convert to your HTTP stack specific output. For example, @vladbasin/strong-api-middleware-aws-lambda converts it to AWS Lambda function response.

`typescript
export type RawApiResponseType = {
statusCode: number;
headers?: MaybeNullable>>;
multiValueHeaders?: MaybeNullable>>;
body?: MaybeNullable;
};
``

In addition, you can share request/response models with your API consumers, so they don't need to repeat the same mapping & validation logic. See: @vladbasin/strong-api-client