Custom authorizer data with Amazon.Lambda.AspNetCoreServer

Question

Having worked extensively with Node.js in the past, we are currently investigating ASP.NET Core as an alternative Lambda platform.

In the past, our API Gateway-fronted s

Answer 1

We've in the exact same situation and I can by no means offer a nice and clean solution, but I have a workaround.

If you look at the request payload, the json is formatted like this:

{
    [...]
    "requestContext": {
        [...]
        "authorizer": {
            "claims": {
                "claim1": "value1",
                "claim2": "value2",
                "claim3": "value3",
            }
        },
        [...]

In APIGatewayProxyFunction.FunctionHandlerAsync they deserialize the requestStream into an APIGatewayProxyRequest. If you step into that class you'll find that the Authorizer part of the json gets deserialized into:

public class APIGatewayCustomAuthorizerContext
{
    public string PrincipalId { get; set; }
    public string StringKey { get; set; }
    public int? NumKey { get; set; }
    public bool? BoolKey { get; set; }
}

I.e all claims are lost in deserialization. I've posted this issue here: https://github.com/aws/aws-lambda-dotnet/issues/98

Now to the workaround, I've just put something that "works" together here (Code here):

Note that it's very untested. :-)

Usage:

public class LambdaEntryPoint : APIGatewayAuthorizerProxyFunction
{
    protected override void Init(IWebHostBuilder builder)
    {
        builder
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup()
            .UseApiGateway();
    }
}