@nexus-navigators/lambda-http-interceptor

@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.