http-lambda-proxy

Node.js library that allows to proxy HTTP requests to AWS Lambda functions. The goal is to empower developers to consider step by step migration of endpoints/workflows and even fully featured HTTP/REST services into serverless.

What is AWS Lambda?

Install

npm i http-lambda-proxy

Usage

The following example describe how to use http-lambda-proxy with restana:

const lambdaProxy = require('http-lambda-proxy')
const proxy = lambdaProxy({
  target: process.env.FUNCTION_NAME,
  region: process.env.AWS_REGION
})

const service = require('restana')()
service.all('/*', (req, res) => { 
  proxy(req, res, req.url, {}))
}) 

service.start(8080)

In this example, we proxy all http requests on port 8080 to an AWS Lambda function.

Example lambda function implementation:

const serverless = require('serverless-http')
const json = require('serverless-json-parser')
const query = require('connect-query')

const service = require('restana')()
service.use(query())
service.use(json())

// routes
service.get('/get', (req, res) => {
  res.send({ msg: 'Go Serverless!' })
})
service.post('/post', (req, res) => {
  res.send(req.body)
})

// export handler
module.exports.handler = serverless(service)

API

Options

region *

Set the AWS Region of the target downstream lambda.

target *

AWS Lambda funcion name, version, or alias.

logType

Set to "Tail" to include the execution log in the response. Default: "None"

qualifier

Specify a version or alias to invoke a published version of the function.

clientContext

Up to 3583 bytes of base64-encoded data about the invoking client to pass to the function in the context object.

lambdaProxy

Function wrapper to AWS Lambda invocation proxy. Allows to overwrite default implementation.

Any other AWS.Lambda constructor option is allowed: https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/Lambda.html

More details on aws-sdk / lambda / invoke: https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/Lambda.html#invoke-property

Proxying

proxy(
  originReq,                          // http.IncomingMessage 
  originRes,                          // http.ServerResponse
  req.url,                            // Request URL
  {}                                  // Options described below
)

Options

onResponse(req, res, response)

Called when the remote lambda response is received. If defined, default behavior is overwritten.

rewriteHeaders(headers)

Called to rewrite the headers of the response, before them being copied over to the outer response. It must return the new headers object.

Supported response formats

The following alternatives describe the supported response formats:

• Ideally, your lambda function is implemented using the serverless-http module, so you can run fully featured Node.js REST/HTTP services as AWS Lambda funtions.
• Your lambda respond using a JSON Payload with the following format:

  {
    "headers": {
      // ...
    },
    "statusCode": 200,
    "body": // ...
  }

• Your lambda respond with a JSON Payload and it contains a body property:

  exports.handler = async function () {
    return JSON.stringify({
      body: "Hello World!"
    })
  }

The lambda function implementation is NOT restricted to Node.js, you can use any of the supported AWS Lambda runtimes.

Related topics

• fast-gateway: https://www.npmjs.com/package/fast-gateway
• fast-proxy: https://www.npmjs.com/package/fast-proxy

License

MIT

Sponsors

• (INACTIVE) Kindly sponsored by ShareNow, a company that promotes innovation!

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