Lambda function URL not returning multiple cookies

Question

I have a Lambda function URL that needs to return multiple cookies. Unlike API Gateway, it would appear that there may be a bug in the Lambda function URL code. I have the following sample code ``` def lambda_handler(event, context): return { 'statusCode': 200, 'headers': { 'Content-Type': 'text/html', 'Set-Cookie' : [ 'cookie1=hello; Secure; HttpOnly;', 'cookie2=howdy; Secure; HttpOnly;' ] }, 'body': '

Hello

Lambda rocks!

' } ``` When executing the URL (eg `curl https://xxxxx.lambda-url.ap-southeast-2.on.aws/ -v 2>&1 | grep "set-cookie"`) I would expect to see something like ``` set-cookie: cookie1=hello; Secure; HttpOnly; set-cookie: cookie2=howdy; Secure; HttpOnly; ``` Instead, the function URL mangles up the output, and returns something like this ` set-cookie: [cookie1=hello; Secure; HttpOnly;, cookie2=howdy; Secure; HttpOnly;] ` There is precedent for using multiValueHeaders with Lambda through API gateway (see https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format) yet the same functionality does not appear to exist on Lambda Function URLs. Have you been able to send multiple cookies from a Lambda function through the function URLs, and how were you able to achieve it in your environment?

Daniel ABIB · Answer

Use multiValueHeaders instead of headers..

```
const response = {
        statusCode: 200,
        multiValueHeaders : {"Set-Cookie": [`language=${language}`, `theme=${theme}`]},
        body: JSON.stringify('User profile set successfully')
    };
```

Allan Pedin · Answer

So multivalueValueHeaders doesnt work as per format 2.0:

https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html

Which points you to use "cookies" field:

https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html#http-api-develop-integrations-lambda.v2:~:text=To%20customize%20the%20response%2C%20your%20Lambda%20function%20should%20return%20a%20response%20with%20the%20following%20format.

Which also doesn't work which leaves us with "case iteration":

```
# python 3
  response = {
        "statusCode": 200,
        "headers": {
            "Set-cookie": "cookie1=1",
            "SEt-cookie": "cookie2=2",
            "SET-cookie": "cookie2=2"
        }
    }
```

Or library that maybe accomplishes above:

https://github.com/Jawshua/aws-lambda-cookies/tree/master

stormpike · Answer

As per the 2.0 format, you can you the cookies attribute: ``` { "statusCode": 200, "body": "

V2

", "headers": { "Content-Type": "text/html" }, "cookies": [ "CloudFront-Key-Pair-Id=foo; Path=/", "CloudFront-Policy=foo; Path=/", "CloudFront-Signature=foo; Path=/" ] } ``` Link: https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html

Lambda function URL not returning multiple cookies

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