https://github.com/matrus2/aws-websocket-handler

https://github.com/matrus2/aws-websocket-handler

Last synced: about 2 months ago
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• Host: GitHub
• URL: https://github.com/matrus2/aws-websocket-handler
• Owner: matrus2
• License: mit
• Created: 2021-01-13T23:19:02.000Z (almost 4 years ago)
• Default Branch: main
• Last Pushed: 2021-01-21T22:10:40.000Z (almost 4 years ago)
• Last Synced: 2024-10-13T11:14:39.038Z (3 months ago)
• Language: TypeScript
• Size: 8.79 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# aws-websocket-handler

[![TypeScript](https://img.shields.io/badge/%3C%2F%3E-TypeScript-%230074c1.svg)](http://www.typescriptlang.org/)

This module is created to handle AWS Lambda websocket actions as a one default handler. There are multiple benefits of doing so:

- all actions are handled by one lambda function;

- no cold start for actions, which are rarely used;

- the codebase is sharable accross all actions;

### How it works?

When you want to use WebSocket API in API Gateway, which are integrated with Lambda functions it is required to specify two mandatory routes $connect and $disconnect. The approach is presented in detail [here](https://aws.amazon.com/blogs/compute/announcing-websocket-apis-in-amazon-api-gateway/). Instead of specifing all actions as separate functions we use here a power of $default route, which is invoked every time no matching expresion is found. This package use `action` parameter from payload.

#### How to use?

1. Install the package:

```

npm i aws-websocket-handler

```

2. Use in your lambda handler:

```

// Typescript

import { APIGatewayProxyEvent, Context } from 'aws-lambda';

import { Configuration, websocketHandler } from 'aws-websocket-handler';

import { validateToken } from './middlewares/validateToken';

import { simpleAction } from './actions/simple';

const config: Configuration = {

    actions: [

        {

            name: 'simple',

            handler: simpleAction,

        },

    ],

    middlewares: [validateToken],

};

exports.handler = async (

    event: APIGatewayProxyEvent,

    context: Context

): Promise => {

    return websocketHandler(event, context, config);

};

// Javascript

const { websocketHandler } = require("aws-websocket-handler");

const { validateToken } = require("./middlewares/validateToken");

const { simpleAction } = require("./actions/simple");

const config = {

    actions: [

        {

            name: 'simple',

            handler: simpleAction,

        }

    ],

    middlewares: [validateToken],

};

exports.handler = async (event, context) => {

    return websocketHandler(event, context, config);

};

```

#### Configuration:

| Param  | Description | Required

| ------------- | ------------- | ------------- |

| actions | Array of ActionsHandlers | optional 

| middlewares  | Array of Middlewares | optional

| fallback  | Fallback promise to be invoked if no action expression is found | optional

| enableLogging  | Boolean param to enable simple logging | optional

##### ActionsHandler example

Name corresponds to `Event.body.action`, if the expression matches, the handler function is invoked. 

```

const simpleAction = async (event, context, runData) => {

    console.log(runData);

    return {};

};

```

##### Middleware example

```

const validateToken = async (event, _context, runData) => {

    const { token } = JSON.parse(event.body);

    if (!token)

        throw new Error('No token');

    let tokenData;

    try {

        tokenData = JWT.verify(token, config_1.KEY);

    }

    catch (e) {

        throw new Error(e.message);

    }

    return { ...runData, tokenData };

};

```

##### Fallback

```

const fallback = async () => {

  return { statusCode: 200, body: 'fallback' }

},

```