Aws-lambda-dotnet: Getting binary support working in blueprint ASP.NET Core Web App

[mbp]

I am having some problems getting binary support working with the ASP.NET Core 2 integration.

So I tried with the "ASP.NET Core Web App" blueprint, and it actually contains a favicon.ico file, which is not displayed when published.

I think the blueprint should work out of the box in the same way as running on your own machine. Or maybe you should just remove the favicon.ico.

I read the instructions with regards to Binary Response Content here: https://github.com/aws/aws-lambda-dotnet/blob/master/Libraries/src/Amazon.Lambda.AspNetCoreServer/README.md

So I added the following line to LambdaEntryPoint.Init(): RegisterResponseContentEncodingForContentType("image/x-icon", ResponseContentEncoding.Base64);

And I added the Binary Media Type in console:

Lambda log correctly shows that response is base64 encoded:

START RequestId: 11a7e691-22d3-11e8-9b13-ef274abd9c03 Version: $LATEST
Incoming GET requests to /favicon.ico
ASP.NET Core Request PathBase: /Prod, Path: /favicon.ico
[Information] Microsoft.AspNetCore.Hosting.Internal.WebHost: Request starting GET https://XXX.execute-api.eu-west-1.amazonaws.com/Prod/favicon.ico 
[Information] Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware: Sending file. Request path: '/favicon.ico'. Physical path: '/var/task/wwwroot/favicon.ico' 
[Information] Microsoft.AspNetCore.Hosting.Internal.WebHost: Request finished in 0.5675ms 200 image/x-icon 
Response Base 64 Encoded: True
END RequestId: 11a7e691-22d3-11e8-9b13-ef274abd9c03

API Gateway log:

Starting execution for request: 577e5bb3-22d4-11e8-b061-1775958b34a4
HTTP Method: GET, Resource Path: /favicon.ico
Successfully completed execution
Method completed with status: 200

What part am I missing?

I found quite many posts with people not making binary work with the lambda proxy integration. So I suspect there is a general issue.

[mbp]

I resolved this issue when talking to AWS Support.

The solution:
After changing "Binary Media Types", you must go and click "Deploy API":

[cjnoname]

Hey bro, I followed your steps but still could not get the image/icon.

Did you do anything more than what you said?

Thanks!

[mbp]

Yeah, actually you need to set BinaryMediaTypes to */* when trying to show the image in the browser.

BinaryMediaType image/x-icon will only work if client sends Accept header. Here is a way to test:

$ curl -sH "Accept: image/x-icon" https://XXX.execute-api.eu-west-1.amazonaws.com/Prod/favicon.ico -o /tmp/favicon.ico
$ file /tmp/favicon.ico
/tmp/favicon.ico: MS Windows icon resource - 3 icons, 16x16, 256-colors

[cjnoname]

ignore it :)

[badcommandorfilename]

I'm just going to leave this here so it hopefully saves someone else an hour...

The default "Accept" header in the request for .png files is "image/apng" not "image/png"! Everything worked once I added:

        protected override void Init(IWebHostBuilder builder)
        {
            //NB: Serverless WebAPI needs to have special config to serve binary file types: 
            RegisterResponseContentEncodingForContentType("image/png", ResponseContentEncoding.Base64);
            RegisterResponseContentEncodingForContentType("image/jpeg", ResponseContentEncoding.Base64);
            RegisterResponseContentEncodingForContentType("image/gif", ResponseContentEncoding.Base64);
            RegisterResponseContentEncodingForContentType("image/apng", ResponseContentEncoding.Base64);
            RegisterResponseContentEncodingForContentType("image/webp", ResponseContentEncoding.Base64);
            RegisterResponseContentEncodingForContentType("image/x-icon", ResponseContentEncoding.Base64);

            builder
                .UseStartup<Startup>();
        }

Edit: Accept headers for Chrome and IE11 seem to use image/apng as default but Firefox sends */* for <img> tags! You can add */* to the above list, and it _seems_ to work but YMMV.