@nexus-navigators/lambda-http-interceptor

Node.js http interceptor for Lambda HTTP APIs

Intercept HTTP calls that are intended to hit a Lambda that resolves API Gateway requests. Use cases include unit tests, integration tests, or connecting directly to a Lambda while bypassing API Gateway.

Installation

npm i --save @nexus-navigators/lambda-http-interceptor

Usage

import { enable, clear, registerIntercept } from '@nexus-navigators/lambda-http-interceptor'

const handler = (event: APIGatewayProxyEventV2) => {
  console.log(event)
  return {
    status: 200,
    body: { out: 'OK' },
  }
}

enable()
registerIntercept({
  eventType: 'apiGatewayProxyV1',
  listenerType: 'handler',
  eventHandler: handler,
  hostMatch: /.*lambda-function\.com.*/,
  eventParams: {
    binaryTypes: [],
  },
  contextParams: {
    functionName: 'testFunction',
    timeout: 1,
  }
})

const response = await fetch('https://lambda-function.com/test')

assert.equal(response.status, 200)
const json = await response.json()
assert.equal(json.out, 'OK')

API

Register Options

| Option | Description | |-----------------|---------------------------------------------------------------------------------------------------------------------------------------| | eventType | The type of event to be sent to the Lambda function. Can be apiGatewayProxyV1 or apiGatewayProxyV2. | | listenerType | The type of listener to be used for invoking the Lambda function. Can be handler or sdk. | | eventHandler | When listenerType is handler then a Lambda handler function must be provided | | hostMatch | A string or RegExp used to match hosts for requests. Can be blank if all HTTP requests should be sent to the function. | | eventParams | An object containing API Gateway parameters to be passed to the Lambda function. | | contextParams | An object containing Lambda context parameters to be passed to the Lambda function. Required when setting listenerType to handler |

Event Parameters

| Parameter | Description | |-----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------| | binaryTypes | An array of binary types to be passed to the Lambda function. The interceptor will convert these kinds of requests to base64 and set the APIGateway event flag | | authorizer (optional) | Any authorization parameters that the API Gateway would have added to the event | | pathParameters (optional) | Any path parameters that the API Gateway would have added to the event | | stageVariables (optional) | Any query stage variables that the API Gateway would have added to the event | | resource (optional) | The resource value API gateway would have added to the event |

Context Parameters

Context parameters are only used when listenerType is handler. These help fill out the context parameter when executing the handler.

| Parameter | Description | |---------------------------------|----------------------------------------------------------------| | functionName (required) | The name of the Lambda function. | | timeout (optional) | The timeout for the Lambda function. | | awsRequestId (optional) | A requestID that is typically a UUID. | | memoryLimitInMB (optional) | The memory size for the Lambda function. | | functionVersion (optional) | The version of the Lambda function. | | logStreamName (optional) | A log stream name for CloudWatch Logs. | | invokedFunctionArn (optional) | The ARN for the function | | clientContext (optional) | Any clientContext that would be sent, matches ClientContext. | | identity (optional) | A CognitoIdentity object that would be set by Lambda. |