README.md

Amazon.Lambda.AppSyncEvents

This package contains classes that can be used as input types for Lambda functions that process AppSync events.

Sample Function

The following is a sample class and Lambda function that receives AppSync event record data as an appSyncResolverEvent and logs some of the incoming event data. (Note that by default anything written to Console will be logged as CloudWatch Logs events.)

public void Handler(AppSyncResolverEvent<Dictionary<string, object>> appSyncResolverEvent, ILambdaContext context)
{
    foreach (var item in appSyncResolverEvent.Arguments)
    {
        Console.WriteLine($"AppSync request key - {item.Key}.");
    }

    if (appSyncResolverEvent.Identity != null)
    {
        // Create an instance of the serializer
        var lambdaSerializer = new DefaultLambdaJsonSerializer();

        using (var stream = new MemoryStream(Encoding.UTF8.GetBytes(appSyncResolverEvent.Identity.ToString()!)))
        {
            // When using AMAZON_COGNITO_USER_POOLS authorization
            var cognitoIdentity = lambdaSerializer.Deserialize<AppSyncCognitoIdentity>(stream);

            // When using AWS_IAM authorization
            var iamIdentity = lambdaSerializer.Deserialize<AppSyncIamIdentity>(stream);
        }
    }
}