AWS Lambdaにて、S3からPDFファイルを/tmpにダウンロード。そして、/tmpからS3へアップロード

AWSLambda20171015.cs

using System;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

using Amazon.Lambda.Core;
using Amazon.S3;
using Amazon.S3.Model;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.Json.JsonSerializer))]

namespace AWSLambda20171015
{
    public class Function
    {
        /// <summary>
        /// A simple function that takes a string and does a ToUpper
        /// </summary>
        /// <param name="input"></param>
        /// <param name="context"></param>
        /// <returns></returns>
        public async Task<string> FunctionHandler(string input, ILambdaContext context)
        {
            AmazonS3Client client = new AmazonS3Client(Amazon.RegionEndpoint.USWest2);

            //S3のPDFファイルを/tmpにコピー
            GetObjectRequest requestGet = new GetObjectRequest
            {
                BucketName = "example-bucket-name",
                Key = "input.pdf"
            };

            GetObjectResponse responseGet = await client.GetObjectAsync(requestGet);

            var filename = String.Format("{0}.{1}", DateTime.Now.ToString("yyyyMMddHHmmss"), "input.pdf");
            CancellationToken cancellationToken;
            await responseGet.WriteResponseStreamToFileAsync("/tmp/"+filename, false, cancellationToken).ConfigureAwait(false);

            string[] files = Directory.GetFiles("/tmp/");
            foreach (string s in files)
            {
                Console.WriteLine(s);
            }

            // /tmpのファイルをS3にコピー
            var stream = new FileStream("/tmp/" + filename, FileMode.Open, FileAccess.Read, FileShare.Read);
            PutObjectRequest request = new PutObjectRequest()
            {
                BucketName = "example-bucket-name",
                Key = filename,
                ContentType = "application/pdf",
                InputStream = stream,
                //FilePath = filename
            };

            try
            {
                await client.PutObjectAsync(request);
                Console.WriteLine( "OK");
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }

            return input?.ToUpper() + "/abc";

        }

    }

}