Bug: CORS support doe not add headers to response

[dave-dotnet-overall]

Expected Behaviour

After following the document to enable CORS when i execute my lambda via api gateway from postman there are no CORS headers been added to the response. I have tried every documented option but to no avail, so either there is documentation missing or this is a bug

Current Behaviour

After enabling CORS i would expect to see the CORS headers been added to the response before it is sent back to the client.

Code snippet

Just copy what is in the documentation and inspect the returned headers in postman.

Possible Solution

No response

Steps to Reproduce

Just copy what is in the documentation and inspect the returned headers in postman.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.12

Packaging format used

Lambda Layers

Debugging logs

[boring-cyborg]

Thanks for opening your first issue here! We'll come back to you as soon as we can.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[leandrodamascena]

Hi @dave-dotnet-overall! Thanks for opening this issue! Can you pls give me more details?

• What headers are you using in this request?
• What HTTP method?
• Do you have CORS enabled in APIGW or not?

Thanks

[dave-dotnet-overall]

hi @leandrodamascena

Nor sure what you mean what headers im using in this request, basically my React developer said they got an error saying "CORS error: "CORS header 'Access-Control-Allow-Origin' missing." when they tried to connect to the API and the reason was because i am not sending CORS headers back. Ive looked at the output from the APIGatewayResolver in the lambda handler and sure enough there are no CORS headers been injected by powertools even though i have set up them according to the documentation.

HTTP method is GET

According to the AWS docs for Lamba with proxy integration it is the responsibility of the lambda function to return the headers and not api gw

[dave-dotnet-overall]

Turns out the react developers were not sending an "Origin" header with their request and as a result the server does not send the CORS headers

[leandrodamascena]

Turns out the react developers were not sending an "Origin" header with their request and as a result the server does not send the CORS headers

Hi @dave-dotnet-overall, thanks for updating this issue! Yes, that's why I asked what headers you were using to make this request. CORs needs the Origin header to trigger the validation and Postman doesn't send the Origin header by default.

Please reopen this issue if you need any other help.

[github-actions]

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