Returning binary body and http headers from an AWS lambda through API gateway

Question

I have a lambda that needs to return a binary object and some http headers (e.g. content-type) through an api gateway (using lambda integration) OR redirect to another URL.

Answer 1

I've been struggling to do the same for days, but couldn't find any documentation to back up that it's possible, instead I found this https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-payload-encodings-workflow.html

When converting a text payload to a binary blob, API Gateway assumes that the > text data is a Base64-encoded string and outputs the binary data as a Base64-decoded blob. If the conversion fails, it returns a 500 response indicating an API configuration error. You do not provide a mapping template for such a conversion, although you must enable the passthrough behaviors on the API.

When converting a binary payload to a text string, API Gateway always applies > a Base64 encoding on the binary data. You can define a mapping template for such a payload, but can only access the Base64-encoded string in the mapping template through $input.body, as shown in the following excerpt of an example > mapping template.

which sounds to me that mapping like this is only possible the other way around; what I ended up doing is that just return Base64Encoded binary string and hard code the content-type and cache- control in header mapping; for the complete implementation see my blog post https://mesfinmoges.com/dynamic-image-resizing-using-amazon-s3-aws-lambda-mazon-api-gateway-amazon-cloudfront/