lambdacookie

Have you ever needed to set multiple cookies in a lambda response served through API Gateway? AWS doesn't natively support setting arrays as header values (which is an ongoing issue here), therefore we need to get creative with header naming to make it work. This library should make your life moderately easier by doing it for you.

Installation

This package is available on pypi. Install using pip:

pip install lambdacookie

Usage

This library is tested with a Serverless deployment, but it should work with any Lambda function behind an API Gateway. Simply call lambdacookie.headers with a list of cookies and a dict of headers will be returned. The returned dict can be output directly from the handler.

A basic multi-cookie serving handler looks something like this:

import lambdacookie

def cookies_handler(event, context):
    cookie = http.cookies.SimpleCookie("tracking_you=intently")
    cookie["tracking_you"]["expires"] = 3600

    headers = lambdacookie.headers([
        'session_cookie=1',
        cookie
    ])
    headers["content-type"] = "text/html"

    return {
        "statusCode": 200,
        "body": "I'm totally tracking you right now",
        "headers": headers
    }

We can fire off a request to the the endpoint to confirm it's working:

# curl https://asdasdasd.execute-api.eu-central-1.amazonaws.com/dev/cookies -v

> GET /dev/cookies HTTP/2
> Host: asdasdasd.execute-api.eu-central-1.amazonaws.com
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/2 200
< content-type: text/html
...
< set-cookie: session_cookie=1
< set-cookie: tracking_you=intently; expires=Tue, 05 Dec 2017 15:49:38 GMT
<
I'm totally tracking you right now

If you're making use of custom header mapping then you can specify a custom header name by passing it in the header kwarg to lambdacookie.headers.

Related Links

• The header generation method was largely inspired by the lamba-proxy-utils and binary-case packages for NodeJS.