Add the json-deserializer middleware package

README.md

@@ -19,6 +19,8 @@ This monorepo is a collection of middleware for AWS lambda functions.
   AWS lambdas.[![downloads](https://img.shields.io/npm/dw/%40lambda-middleware%2Fie-no-open.svg)](https://npmjs.org/package/@lambda-middleware/ie-no-open)
 * [@lambda-middleware/json-serializer](packages/json-serializer): A middleware for AWS http lambda functions to
   serialize JSON responses.[![downloads](https://img.shields.io/npm/dw/%40lambda-middleware%2Fjson-serializer.svg)](https://npmjs.org/package/@lambda-middleware/json-serializer)
+* [@lambda-middleware/json-deserializer](packages/json-deserializer): A middleware for AWS http lambda functions to
+  deserialize JSON request bodies.[![downloads](https://img.shields.io/npm/dw/%40lambda-middleware%2Fjson-deserializer.svg)](https://npmjs.org/package/@lambda-middleware/json-deserializer)
 * [@lambda-middleware/jwt-auth](packages/jwt-auth): A middleware for AWS http lambda functions to verify JWT auth
   tokens inspired by express-jwt.[![downloads](https://img.shields.io/npm/dw/%40lambda-middleware%2Fjwt-auth.svg)](https://npmjs.org/package/@lambda-middleware/jwt-auth)
 * [@lambda-middleware/middy-adaptor](packages/middy-adaptor): An adaptor to use middy middleware as functional

common/changes/@lambda-middleware/json-deserializer/feature-json-deserializer_2021-08-30-23-27.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@lambda-middleware/json-deserializer",
+      "comment": "Added json-deserializer lambda-middleware package",
+      "type": "minor"
+    }
+  ],
+  "packageName": "@lambda-middleware/json-deserializer",
+  "email": "matt@jenner.me.uk"
+}

packages/json-deserializer/.eslintrc.js

@@ -0,0 +1,12 @@
+module.exports = {
+  extends: [
+    "plugin:@typescript-eslint/recommended",
+    "prettier/@typescript-eslint",
+    "plugin:prettier/recommended",
+  ],
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    project: "tsconfig.json",
+    sourceType: "module",
+  },
+};

packages/json-deserializer/.gitignore

@@ -0,0 +1,29 @@
+# See https://help.github.com/ignore-files/ for more about ignoring files.
+
+# IDEs
+.idea
+
+# dependencies
+/node_modules
+
+# testing
+/coverage
+
+# production
+/build
+
+# misc
+.DS_Store
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+package-lock.json
+yarn-debug.log*
+yarn-error.log*
+yarn.lock
+
+# Built library
+lib

packages/json-deserializer/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 Matt Jenner
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/json-deserializer/README.md

@@ -0,0 +1,54 @@
+# @lambda-middleware/json-deserializer
+
+[![npm version](https://badge.fury.io/js/%40lambda-middleware%2Fjson-deserializer.svg)](https://npmjs.org/package/@lambda-middleware/json-deserializer)
+[![downloads](https://img.shields.io/npm/dw/%40lambda-middleware%2Fjson-deserializer.svg)](https://npmjs.org/package/@lambda-middleware/json-deserializer)
+[![open issues](https://img.shields.io/github/issues-raw/dbartholomae/lambda-middleware.svg)](https://github.com/dbartholomae/lambda-middleware/issues)
+[![debug](https://img.shields.io/badge/debug-blue.svg)](https://github.com/visionmedia/debug#readme)
+[![build status](https://github.com/dbartholomae/lambda-middleware/workflows/.github/workflows/build.yml/badge.svg?branch=main)](https://github.com/dbartholomae/lambda-middleware/actions?query=workflow%3A.github%2Fworkflows%2Fbuild.yml)
+[![codecov](https://codecov.io/gh/dbartholomae/lambda-middleware/branch/main/graph/badge.svg)](https://codecov.io/gh/dbartholomae/lambda-middleware)
+[![dependency status](https://david-dm.org/dbartholomae/lambda-middleware.svg?theme=shields.io)](https://david-dm.org/dbartholomae/lambda-middleware)
+[![devDependency status](https://david-dm.org/dbartholomae/lambda-middleware/dev-status.svg)](https://david-dm.org/dbartholomae/lambda-middleware?type=dev)
+
+A middleware for AWS http lambda functions to deserialize incoming requests containing a json body.
+
+Depending on the request payload and header the following can happen:
+
+- **The event has a valid json content-type header** (eg. `application/json`), and:
+  - **The body contains a valid JSON payload** - `body` is deserialized and added back to the event object as `bodyObject` with a type of `Record<string, unknown>`.
+  - **The body has invalid JSON payload** - the middleware throws a `RequestBodyNotJsonError`.
+- **The event has a non json content-type header** - the middleware will add a `bodyObject` property with `null`.
+- **The event has no body set** - the middleware will add a `bodyObject` property with `null`.
+
+Please note that this middleware just provides a basic object to the handler without typing for the properties, you will need to handle validation of the request body object separately.
+
+## Lambda middleware
+
+This middleware is part of the [lambda middleware series](https://dbartholomae.github.io/lambda-middleware/). It can be used independently.
+
+## Usage
+
+```typescript
+import { jsonDeserializer } from "@lambda-middleware/json-deserializer";
+import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";
+import { APIGatewayProxyObjectEvent } from "../lib/types/APIGatewayProxyObjectEvent";
+
+// This is your AWS handler
+async function helloWorld(
+  request: APIGatewayProxyObjectEvent<APIGatewayProxyEvent>
+): Promise<APIGatewayProxyResult> {
+  // We can simply pick out the body object from the request and use it
+  const { bodyObject } = request ?? {};
+
+  // Do something with the object and return it
+  return {
+    statusCode: 200,
+    body: JSON.stringify({
+      ...bodyObject,
+      additionalThing: "addedInHandler",
+    }),
+  };
+}
+
+// Wrap the handler with the middleware
+export const handler = jsonDeserializer()(helloWorld);
+```