event.resource in catch-all route gets + changed to *

[jakub-g]

Bug Report

Context

With AWS, it's possible to define wildcard / "catch-all" routes using /stuff/{wildcard+} syntax in YML file:

https://stackoverflow.com/questions/35773025/is-it-possible-to-use-wildcards-or-catch-all-paths-in-aws-api-gateway

Then path of the requested resource is available as event.resource in the handler.

Problem

The value of event.resource is different under serverless vs serverless-offline:

Expected: /stuff/{wildcard+} (matching YML entry; this is how serverless works)
Actual: /stuff/{wildcard*} (serverless-offline converts + to * for some reason 🤔 )

Sample Code

• file: serverless.yml

functions:
  myfunc:
    events:
      - http:
          path: '/stuff/{wildcard+}'
          method: 'GET'

• file: handler.js

exports.hello = async function hello(event) {
  return {
    body: JSON.stringify({ resource: event.resource }),
    statusCode: 200,
  }
}

Versions

This is not new, has been happening for a while, but I didn't report it before as I wanted to update all versions first

• serverless version: 3.17.0 (happening with 2.x too)
• serverless-offline version: 8.8.0 (happening with 7.x too)
• node.js version: 14.19 or 16.15
• OS: macOS 12.4

[dnalborczyk]

thank you for reporting!

I haven't looked into this yet, but one possibility you are experiencing this issue is that * is being used by hapi (the underlying REST engine powering serverless-offline) to define wildcard routes. just a bad guess.

[Ankcorn]

I ran into this working on an api gateway adapter

@Lilja created some event bodies comparing serverless offline to apigateway to verify this

Api Gateway Rest Api

{
  resource: '/leading/prefix/{proxy+}',
  path: '/leading/prefix/test/thing',
  httpMethod: 'GET',
  headers: {
    accept: '*/*',
    Host: 'censored',
    'User-Agent': 'curl/7.83.1',
    'X-Amzn-Trace-Id': 'Root=1-62cd6757-7259b8dd7b8f145033708acd',
    'X-Forwarded-For': 'censored',
    'X-Forwarded-Port': '443',
    'X-Forwarded-Proto': 'https'
  },
  multiValueHeaders: {
    accept: [ '*/*' ],
    Host: [ 'censored' ],
    'User-Agent': [ 'curl/7.83.1' ],
    'X-Amzn-Trace-Id': [ 'Root=1-62cd6757-7259b8dd7b8f145033708acd' ],
    'X-Forwarded-For': [ 'censored' ],
    'X-Forwarded-Port': [ '443' ],
    'X-Forwarded-Proto': [ 'https' ]
  },
  queryStringParameters: null,
  multiValueQueryStringParameters: null,
  pathParameters: { proxy: 'test/thing' },
  stageVariables: null,
  requestContext: {
    resourceId: 'censored',
    resourcePath: '/leading/prefix/{proxy+}',
    httpMethod: 'GET',
    extendedRequestId: 'VJ0VvFLiIAMFiOQ=',
    requestTime: '12/Jul/2022:12:21:43 +0000',
    path: '/dev/leading/prefix/test/thing',
    accountId: '328886342752',
    protocol: 'HTTP/1.1',
    stage: 'dev',
    domainPrefix: 'qtdldn2207',
    requestTimeEpoch: 1657628503765,
    requestId: 'ff7a0efa-97df-4a02-abee-cbaa1927c0a5',
    identity: {
      cognitoIdentityPoolId: null,
      accountId: null,
      cognitoIdentityId: null,
      caller: null,
      sourceIp: 'censored',
      principalOrgId: null,
      accessKey: null,
      cognitoAuthenticationType: null,
      cognitoAuthenticationProvider: null,
      userArn: null,
      userAgent: 'curl/7.83.1',
      user: null
    },
    domainName: 'censored',
    apiId: 'censored'
  },
  body: null,
  isBase64Encoded: false
}

Serverless Offline

{
  body: null,
  headers: {
    'content-type': 'application/json',
    Accept: '*/*',
    'User-Agent': 'node-fetch/1.0 (+https://github.com/bitinn/node-fetch)',
    'Accept-Encoding': 'gzip,deflate',
    Connection: 'close',
    Host: 'localhost:4050'
  },
  httpMethod: 'GET',
  isBase64Encoded: false,
  multiValueHeaders: {
    'content-type': [ 'application/json' ],
    Accept: [ '*/*' ],
    'User-Agent': [ 'node-fetch/1.0 (+https://github.com/bitinn/node-fetch)' ],
    'Accept-Encoding': [ 'gzip,deflate' ],
    Connection: [ 'close' ],
    Host: [ 'localhost:4050' ]
  },
  multiValueQueryStringParameters: { batch: [ '1' ], input: [ '{"0":{"name":"Erik"}}' ] },
  path: '/leading/prefix//greet',
  pathParameters: { proxy: '/greet' },
  queryStringParameters: { batch: '1', input: '{"0":{"name":"Erik"}}' },
  requestContext: {
    accountId: 'offlineContext_accountId',
    apiId: 'offlineContext_apiId',
    authorizer: {
      claims: undefined,
      scopes: undefined,
      principalId: 'offlineContext_authorizer_principalId'
    },
    domainName: 'offlineContext_domainName',
    domainPrefix: 'offlineContext_domainPrefix',
    extendedRequestId: 'cl5htiwtg0000h2tw6mh1cc7d',
    httpMethod: 'GET',
    identity: {
      accessKey: null,
      accountId: 'offlineContext_accountId',
      apiKey: 'offlineContext_apiKey',
      apiKeyId: 'offlineContext_apiKeyId',
      caller: 'offlineContext_caller',
      cognitoAuthenticationProvider: 'offlineContext_cognitoAuthenticationProvider',
      cognitoAuthenticationType: 'offlineContext_cognitoAuthenticationType',
      cognitoIdentityId: 'offlineContext_cognitoIdentityId',
      cognitoIdentityPoolId: 'offlineContext_cognitoIdentityPoolId',
      principalOrgId: null,
      sourceIp: '127.0.0.1',
      user: 'offlineContext_user',
      userAgent: 'node-fetch/1.0 (+https://github.com/bitinn/node-fetch)',
      userArn: 'offlineContext_userArn'
    },
    operationName: undefined,
    path: '/leading/prefix//greet',
    protocol: 'HTTP/1.1',
    requestId: 'cl5htiwtg0001h2tw3l8w3l98',
    requestTime: '12/Jul/2022:08:54:33 +0200',
    requestTimeEpoch: 1657608873887,
    resourceId: 'offlineContext_resourceId',
    resourcePath: '/dev/leading/prefix/{proxy*}',
    stage: 'dev'
  },
  resource: '/leading/prefix/{proxy*}',
  stageVariables: null
}

I think its related to this line here

serverless-offline/src/events/http/lambda-events/LambdaProxyIntegrationEvent.js

Line 159 in 4377f45

const resource = this.#routeKey || route.path.replace(`/${this.#stage}`, '')

Is this the fix

const resource = this.#routeKey || route.path.replace(`/${this.#stage}`, '').replace('*','+')

[Ankcorn]

Hey @dnalborczyk if I made a PR with that fix do you think it would be merged?

[dnalborczyk]

Hey @dnalborczyk if I made a PR with that fix do you think it would be merged?

@Ankcorn that would be great. I don't see why not!?