How to access HTTP headers for request to AWS API Gateway using Lambda?

Question

I see in the API Gateway FAQ that it is possible to access the request headers sent to the API Gateway...

If you already utilize OAuth tokens or any o

Answer 1

This is an example event object:

{
"requestContext": {
    "elb": {
        "targetGroupArn": "arn:aws:elasticloadbalancing:us-east-2:123456789012:targetgroup/lambda-279XGJDqGZ5rsrHC2Fjr/49e9d65c45c6791a"
    }
},
"httpMethod": "GET",
"path": "/lambda",
"queryStringParameters": {
    "query": "1234ABCD"
},
"headers": {
    "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8",
    "accept-encoding": "gzip",
    "accept-language": "en-US,en;q=0.9",
    "connection": "keep-alive",
    "host": "lambda-alb-123578498.us-east-2.elb.amazonaws.com",
    "upgrade-insecure-requests": "1",
    "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36",
    "x-amzn-trace-id": "Root=1-5c536348-3d683b8b04734faae651f476",
    "x-forwarded-for": "72.12.164.125",
    "x-forwarded-port": "80",
    "x-forwarded-proto": "http",
    "x-imforwards": "20"
},
"body": "",
"isBase64Encoded": false

}

The event object contains "headers" in it, you can access request headers sent to API gateway by using: event.headers.<header key>