Geolocation service with AWS API Gateway and Lambda

Question

What we are trying to do

We are trying to set up a very simple Geolocation service with API Gateway and Lambda.

Very similar to https://ipstack.com/, but we don't want to use an external service as we believe it could be an issue in some jurisdictions to send a non-anonymized IP address to a service we don't control (before getting the user's consent).

Would like to have a simple api https://location.my-site.com that returns the country (for GDPR, cookies, etc purposes).

Now it seems that there is a light Cloudfront behind API Gateway that would produce the header "Cloudfront-Viewer-Country", which would be very simple and achieve what we need. i.e. lambda receives Cloudfront-Viewer-Country and just sends it back.

What we have tried

I have seen solutions such as this one: Build a Geolocation API using AWS Lambda and MaxMind, but I struggle to see why deploying an RDS and maintaining the MaxMind database would make sense for us, if it is already available from Cloudfront-Viewer-Country.

I have seen this question: Accessing cloudfront-viewer-country header in AWS API Gateway using HTTP Proxy?, and tried implementing the answer from Michael - sqlbot. But I cannot seem to access the headers.

I have also tried what is suggested in this post, but I can't seem to access the value of Cloudfront-Viewer-Country either.

What we are doing (in conjunction with 'What we have tried')

To access and check if the header is available I am using the following python lambda function

import json
 
def lambda_handler(event, context):

    response = {
        'status': '200',
        'statusDescription': 'Found',
        'headers': {
            'location' : [ {
                'event': json.dumps(event)
            } ]
        }
    }
 
    return response

What the problem is

but the event json dump doesn't contain Cloudfront-Viewer-Country.

I suspect I'm doing something wrong but I really can't figure it out. Any pointer would be very much appreciated.

Thank you

Are you using a Lambda Proxy integration type in API Gateway? Or are you using a custom integration mapping? If you are using Lambda Proxy and the header is not there then I would suspect you need to enable caching in API Gateway in order to get the CloudFront distribution deployed in front of API Gateway. — Mark B
I am using a custom integration mapping. I also tried Lambda Proxy integration, it gives me the 'most information' but doesn't work (enabled cache as per suggestion but didn't work either) I also tried an http api gateway, but there I don't see any options to add the header — johnaws
The post you linked said they had caching enabled to get the header. Are you sure it doesn't work with caching enabled + proxy integration? — Mark B
Thanks very much Mark B for the help. I couldn't get it to work with caching enabled + proxy integration. I have, finally, managed to get it working... the issue was trying to use Endpoint Type = Regional... Edge optimized worked (without cache, go figure...). I only got CloudFront-Viewer-Country working, but not the other geolocation data, which would have been helpful for CCPA. — johnaws
You might have to place a separate CloudFront distribution in front of the API, instead of just enabling API caching, to get the full set of CloudFront headers. — Mark B

johnaws johnaws · Accepted Answer · 2020-10-14T20:19:58

I was able to get access to Cloudfront-Viewer-Country by setting a Endpoint Type = Edge optimized.

I could not get it to work with Endpoint Type = Regional or with http api gateway.

Geolocation service with AWS API Gateway and Lambda

1 Answers