How do I correctly specify the "path:" when setting up an http event for a Lambda function?

Serverless Framework
1

After much trial and error, I’m going to ask for help on a (seemingly) simple issue.
I’m trying to set up API gateway to handle http requests. My serverless.yml file looks like this:

functions:
  create:
    handler: handlers/createUser.Create
    events:
      - http:
          path: createUser/Create
          method: post
          integration: lambda-proxy
          cors: true

I have a “handlers/” directory at the root of my serverless service, containing the handler “createUser.js”.
Inside of “createUser.js”, I’m exporting like this:
export default function Create(event, context, callback) {
…
}
After a successful deployment, I’m trying to use the endpoint which is:
https://XXXXXXXX.execute-api.us-east-1.amazonaws.com/dev/createUser/Create
(using the proper url of course, not XXXXXXXX !) , but I keep receiving the same error:
{“message”:“Missing Authentication Token”}

According to this article
http://www.awslessons.com/2017/aws-api-gateway-missing-authentication-token/
There are 3 possible causes of this error, and I’ve eliminated 2 of them, leaving “Incorrect URL String” as the culprit. I feel like I’m probably causing this error by the way I’m specifying my http path and/or handler… any help would be much appreciated!

Note: I’ve also tried this in my sls.yml:
path: createUser/Create
and using this url: https://XXXXXXXX.execute-api.us-east-1.amazonaws.com/dev/handlers/createUser/Create
but the result is the same error.

2

Your formatting is wrong in the serverless.yml file. You need to nest another level deep under http.

functions:
  create:
    handler: handlers/createUser.Create
    events:
      - http:
          path: createUser/Create
          method: post
          cors: true

Also I think you need to not default export your create function.

export function Create(event, context, callback) {
...
}

Hope this helps :sweat_smile:

3

Thank you. I’ll try changing the way I’m exporting my function. My formatting is actually correct in my serverless.yml, but I messed it up while pasting, sorry about that.

Update:
I’ve removed the handlers/ directory from the picture to simplify. My handler function createUser.js is now in the root of my service with my serverless.yml.

I’m exporting my function like this:
export function Create(event, context, callback) {
//code
}

Serverless.yml like this:

functions:
  create:
     handler: createUser.Create
     events:
        - http:
             path: createUser/Create
             method: post
             integration: lambda-proxy
             cors: true

When I test the function "create" in the AWS console, I'm getting this:
 {
  "errorMessage": "Cannot find module '/var/task/createUser'",
  "errorType": "Error",
  "stackTrace": [
    "require (internal/module.js:12:17)"
  ]
}

I should note that I’m using the serverless-babel-plugin as well, but I’m not sure if that’s relevant here or not… It’s possible that the issue is in the packaging of my service

4

It looks like the file is missing. Run sls deploy -n. This should create a zip file inside your .serverless folder. Unzip that file and you can see what’s being uploaded. It may be that serverless-babel-plugin is putting the compiled JS files into another folder (I don’t use it so I’m not sure how it works).

5

Thanks for the tip, will try that now.

6

I managed to get it working. I don’t think the serverless-babel-plugin was an issue, as all the required files seemed to be zipped correctly. ( However, I decided to remove the plugin for other reasons)
In the end, this is what I’m using successfully:

serverless.yml:

functions:
  create:
    handler: handlers/subscribeUser.subscribe
    events:
      - http:
          path: subscribe
          method: post
          integration: lambda-proxy
          cors: true

and in my handler (subscribeUser.js):

exports.subscribe = subscribe;
function subscribe(event, context, callback) {
    // code
}

All is working well now!

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