feat(event_handler): Allow for cookies in response

[michaelbrewer]

Issue number:

• Feature request: Support cookies in Lambda function response for format 2.0 #1192

Summary

Currently there is no simple way to set cookies in the api gateway event handler.

And this is a gap for http api responses which supports a cookie field.

For documentation we may need to call out the following caveats:

• multiValueHeaders is assumed for rest and alb, but only supported by ALB when enabled: ALB - Enable multi-value headers
• cookies is assumed for http api but only supported by http api payload version 2

Changes

Please provide a summary of what's being changed

• Add cookies field in Response
• For http api gateway format 2.0 responses serialize to cookies
• For alb and rest api use multiValueHeaders for cookies

User experience

Please share what the user experience looks like before and after this change

For http api handler

from aws_lambda_powertools.event_handler.api_gateway import APIGatewayHttpResolver, Response

app = APIGatewayHttpResolver()


@app.get("/my/path")
def my_path() -> Response:
    return Response(200, content_types.TEXT_PLAIN, "Foo", cookies=["key=value"])


def handler(event, context):
    return app.resolve(event, context)

Will output a http api payload v2 response:

{
    "statusCode": 200,
    "headers": {
        "Content-Type": "text/plain"
    },
    "body": "Test",
    "isBase64Encoded": false,
    "cookies": [
        "key=value"
    ]
}

For rest api handler

from aws_lambda_powertools.event_handler.api_gateway import APIGatewayHttpResolver, Response

app = APIGatewayRestResolver()


@app.get("/my/path")
def my_path() -> Response:
    return Response(200, content_types.TEXT_PLAIN, "Foo", cookies=["key=value"])


def handler(event, context):
    return app.resolve(event, context)

Outputs the following for ALB and Rest responses

{
    "statusCode": 200,
    "headers": {
        "Content-Type": "text/plain"
    },
    "body": "Test",
    "isBase64Encoded": false,
    "multiValueHeaders": {
        "Set-Cookie": [
            "key=value"
        ]
    }
}

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• Meet tenets criteria
• I have performed a self-review of my this change
• Changes are tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[codecov-commenter]

Codecov Report

Merging #1196 (e2723c3) into develop (9d8dd1b) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #1196   +/-   ##
========================================
  Coverage    99.88%   99.88%           
========================================
  Files          119      119           
  Lines         5423     5429    +6     
  Branches       618      620    +2     
========================================
+ Hits          5417     5423    +6     
  Misses           2        2           
  Partials         4        4           

Impacted Files	Coverage Δ
aws_lambda_powertools/event_handler/api_gateway.py	100.00% <100.00%> (ø)

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[sthulb]

In an effort to prevent you from wasting time, you should wait for issues to prioritised, this won't be merged for a long time until we're ready to add new features.

[michaelbrewer]

More of a gap than a feature. There is no easy way for customers to set cookies