Add binary support

[tmaiaroto]

Add binary support

[tmaiaroto]

This is partially implemented. The media type wildcard */* will now be added to the API (and set on each update). So it's possible to return a file, render an image, etc. Cool!

But...I would still like to allow the value to be configured. While I can't see a problem with simply always keeping a wildcard of */* set (and maybe just do so when the API is first created) and be done with it...I imagine it could be useful to specify the types in the configuration.

Unfortunately, setting the array of media types did not seem to work with Swagger. Which would have made this all easier. So an update API call had to be made...And that call requires a path which is a little funky (and escaped): /binaryMediaTypes/*~1*

Anyway, this could be a bit nicer...And I haven't yet addressed binary coming in. It is possible to accept binary data through API Gateway too. It will then be converted to base64. In fact, on the Lambda side it's always going to be base64 because the Lambda event is of course in JSON.

For now, to return binary data, simply set res.IsBase64Encoded = true and then base64 encode some binary data: res.Body = base64.StdEncoding.EncodeToString(buf.Bytes()) ... I have had success in returning an image and making a simple image resize API with just a few lines of code.

Binary support with API Gateway and Lambda is really cool and convenient. However, for many situations I'd probably look at working with S3 and CloudFront. Specifically with an image resize API, you'd want to keep the results cached and stored somewhere like S3/CloudFront. Of course API Gateway can cache responses...But to scale (even if perhaps only your wallet), you're really looking at S3 anyway. At any rate, binary support is super convenient.

[tmaiaroto]

It may not be possible to accept images when using Lambda Proxy? https://aws.amazon.com/blogs/compute/binary-support-for-api-integrations-with-amazon-api-gateway/

...Or may be that specific routes need contentHandling settings:
http://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-payload-encodings.html

Which might not work so well with a wildcard path.

[tmaiaroto]

I followed this: http://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-payload-encodings-configure-with-control-service-api.html#api-gateway-payload-encodings-setup-with-api-set-integration-request-encoding

It doesn't seem to work just yet. I'm uncertain it will work for Lambda Proxy with ANY requests. In order to be sure, I'll need to change the API Gateway settings to use something else other than Lambda Proxy. Though this starts to remove a lot of convenience.

[tmaiaroto]

Not going to worry about this for now as it's not well suited for AWS Lambda and API Gateway. The preferred method of working with binary data is to upload with pre-signed S3 URLs and then respond with S3 URLs. Though we can also return binary data in responses from API Gateway. So I don't see the need for anything more extravagant. Not for now.