Making a POST request using Superagent, AWS Lambda, API Gateway - aws-lambda

Question

I am using AWS Lambda and API Gateway to create a custom endpoint for load tests. I have uploaded my handler function which is in a file, along with the node modules needed for the function in a zip, and set up the API Gateway API correctly according the instructions (in line with the way that I had made it work before), but I keep getting the error: {"error": "Missing Authentication Token"}. Everything I have seen online thus far points to the idea that the url that I am passing in with the POST request is invalid, but I have made a similar endpoint work with a GET request. As far as I know I have set up the POST request (using Superagent) correctly, and am passing in a valid access-token, as well as hardcoded params as part of the URL (valid params).
// Dependencies
var request = require('superagent');
var sync = require('synchronize');
exports.handler = function(event, context) {
sync.fiber(function() {
// Grabs params passed into the URL as a JSON object
var querystring = (event.querystring);
// Replaces params with an updated version which includes a single quotation
var queryStringUpdate = querystring.replace(/=/g, ":").replace(/}/g, "'}").replace(/:/g, ":'").replace(/,/g, "',");
// Updates the param information and sets it as a new string
eval('var queryString2 =' + queryStringUpdate);
// Define specific query params to be used in the REST calls
var userId = (queryString2.userId === undefined ? '229969' : queryString2.userId);
var roomdId = (queryString2.roomId === undefined ? '4' : queryString2.roomId);
var inviterId = (queryString2.inviterId === undefined ? '212733' : queryString2.inviterId);
var createInvitePost = function() {
request
.post('https://some_url/v2/invites/212733/create')
.set({'access-token': 'some_access_token'})
.set('Content-Type', 'application/json')
.query({user_id: "229969"})
.query({room_jid: "4"})
.end(function(err, res){
if (err) {
context.fail("Uh oh, something went wrong");
} else {
context.done(null, "Hurray, it worked!!");
}
});
};
try {
createInvitePost();
} catch(errOne) {
alert("No bueno!!");
}
});
};
Any thoughts on this?? Thanks

Answer 1

I usually get this error when I've missed some part of the URL needed for my API. In the past it's either been the name of the stage, misspelled resource name, or a missing Path parameter.

Answer 2

I'm from the Api Gateway team.
As others have said, the most common cause of the 403 response you're getting is an incorrect path/method. I'm not familiar with Superagent, but if you've run the same request in Postman and cURL then I would be surprised if you had the wrong path/method.
Maybe also check on a wire log if possible, to make sure that your querystring logic isn't appending a forward slash prior to the '?'.
Some things to check:
Have you deployed any recent changes to your API?
Is the stage 'v2' (I'm assuming that's the stage) pointing at a deployed version of the API that has the POST to invites/212733/create?
The 'access-token' should have no effect on the Api Gateway layer. If you're trying to use a native Api Gateway Api Key, the header is 'x-api-key'.
Jack