node-aws-lambda-handlers

@enter-at/lambda-handlers""> @enter-at/lambda-handlers"">

An opinionated Typescript package that facilitates specifying AWS Lambda handlers including input validation,
error handling and response formatting.

It’s 100% Open Source and licensed under the APACHE2.

Quick Start

Install from NPM:

npm install @enter-at/lambda-handlers

Api

Status code

import {APIGatewayProxyHandler} from '@enter-at/lambda-handlers';
@APIGatewayProxyHandler()
export function handler(event, context) {
    return {
        message: `Hello ${event.queryStringParameters.name}!`
    };
}

Let’s invoke the function:

payload='{"queryStringParameters": {"name": "Peter"}}'
aws lambda invoke --function-name hello-world --payload $payload /tmp/response.json

Responds with:

{
    "headers":{
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Credentials": true,
        "Content-Type": "application/json"
    },
    "statusCode": 200,
    "body": "\"Hello Peter!\""
}

Default headers and status code have been added.

Respond with a specific status code

import {APIGatewayProxyHandler, created} from '@enter-at/lambda-handlers';
@APIGatewayProxyHandler()
export function handler(event, context) {
    const resource = {id: 1, name: event.body.name};
    return created(resource);
}

payload='{"body": "{\"name\": \"Peter\"}"}'
aws lambda invoke --function-name create-resource --payload $payload /tmp/response.json

Responds with:

{
    "headers":{
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Credentials": true,
        "Content-Type": "application/json"
    },
    "statusCode": 201,
    "body": "{\"id\":1,\"name\":\"Peter\"}"
}

Error handling

import {APIGatewayProxyHandler, BadRequestError} from '@enter-at/lambda-handlers';
@APIGatewayProxyHandler()
export function handler(event, context) {
    throw new BadRequestError('missing email');
}

aws lambda invoke --function-name create-resource $payload /tmp/response.json

Responds with:

{
    "headers":{
        "Access-Control-Allow-Origin": "*",
        "Access-Control-Allow-Credentials": true,
        "Content-Type": "application/json"
    },
    "statusCode": 400,
    "body": "{\"errors\":[{\"name\": \"BadRequestError\", \"details\": [\"missing email\"]}]}"
}

Headers

Cors

import {APIGatewayProxyHandler, cors} from '@enter-at/lambda-handlers';
@APIGatewayProxyHandler({
    cors: cors('example.com', false)
})
export function handler(event, context) {
    return {
        message: 'Hello World!'
    };
}

aws lambda invoke --function-name cors /tmp/response.json

Responds with:

{
    "headers":{
        "Access-Control-Allow-Origin": "example.com",
        "Content-Type": "application/json"
    },
    "statusCode": 201,
    "body": "\"Hello World!\""
}

Errors

LambdaHandlerError

BadRequestError

ForbiddenError

InternalServerError

NotFoundError

FormatError

ValidationError

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Related Projects

Check out these related projects.

• python-aws-lambda-handlers - An opinionated Python module that facilitates specifying AWS Lambda handlers including
  input validation, error handling and response formatting.

Help

Got a question?

File a GitHub issue.

Contributing

Bug Reports & Feature Requests

Please use the issue tracker to report any bugs or file feature requests.

Developing

If you are interested in being a contributor and want to get involved in developing this project, we would love to hear from you!

In general, PRs are welcome. We follow the typical “fork-and-pull” Git workflow.

1. Fork the repo on GitHub
2. Clone the project to your own machine
3. Commit changes to your own branch
4. Push your work back up to your fork
5. Submit a Pull Request so that we can review your changes

NOTE: Be sure to merge the latest changes from “upstream” before making a pull request!

License

See LICENSE for full details.

Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at
  https://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.