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http-router

This handler can route to requests to one of a nested handler based on method and path of an http event from API Gateway (REST or HTTP) or Elastic Load Balancer.

Install​

To install this middleware you can use NPM:

npm install --save @middy/http-router

Options​

  • routes (array[{method, path, handler}]) (required): Array of route objects.
    • method (string) (required): One of GET, POST, PUT, PATCH, DELETE, OPTIONS and ANY that will match to any method passed in
    • path (string) (required): AWS formatted path starting with /. Variable: /{id}/, Wildcard: /{proxy+}
    • handler (function) (required): Any handler(event, context) function
  • notFoundResponse (function): Override default 404 error thrown with your own custom response. Passes in {method, path}

NOTES:

  • When using API Gateway it may be required to prefix routes[].path with /{stage} depending on your use case.
  • Errors should be handled as part of the router middleware stack or the lambdaHandler middleware stack. Handled errors in the later will trigger the after middleware stack of the former.
  • Shared middlewares, connected to the router middleware stack, can only be run before the lambdaHandler middleware stack.
  • pathParameters will automatically be set if not already set
  • Path parameters in kebab notation ({my-var}) are not supported. Workaround example below.

Sample usage​

import middy from '@middy/core'
import httpRouterHandler from '@middy/http-router'
import validatorMiddleware from '@middy/validator'

const getHandler = middy()
  .use(validatorMiddleware({eventSchema: {...} }))
  .handler((event, context) => {
    return {
      statusCode: 200,
      body: '{...}'
    }
  })

const postHandler = middy()
  .use(validatorMiddleware({eventSchema: {...} }))
  .handler((event, context) => {
    return {
      statusCode: 200,
      body: '{...}'
    }
  })

const routes = [
  {
    method: 'GET',
    path: '/user/{id}',
    handler: getHandler
  },
  {
    method: 'POST',
    path: '/user',
    handler: postHandler
  }
]

export const handler = middy()
  .use(httpHeaderNormalizer())
  .handler(httpRouterHandler(routes))

Sample kebab usage​

import middy from '@middy/core'
import httpRouterHandler from '@middy/http-router'
import validatorMiddleware from '@middy/validator'
import { kebab } from 'change-case'

const getHandler = middy()
  .before((request) => {
    const key = 'myId'
    request.event.pathParameters[kebab(key)] = request.event.pathParameters[key]
    delete request.event.pathParameters[key]
  })
  .use(validatorMiddleware({eventSchema: {...} }))
  .handler((event, context) => {
    return {
      statusCode: 200,
      body: '{...}'
    }
  })

const postHandler = middy()
  .use(validatorMiddleware({eventSchema: {...} }))
  .handler((event, context) => {
    return {
      statusCode: 200,
      body: '{...}'
    }
  })

const routes = [
  {
    method: 'GET',
    path: '/user/{myId}', // '/user/{my-id}' update to lowerCamelCase
    handler: getHandler
  },
  {
    method: 'POST',
    path: '/user',
    handler: postHandler
  }
]

export const handler = middy()
  .use(httpHeaderNormalizer())
  .handler(httpRouterHandler(routes))