S3 Client Extensions (IAmazonS3) Adds fluent extensions to check if an object exists, and if an object is the same as one in S3.

AmazonS3Extensions.cs

	using System;
	using System.IO;
	using System.Net;
	using System.Security.Cryptography;
	using System.Text;
	using Amazon;
	using Amazon.S3;
	using Amazon.S3.Model;

  public static class AmazonS3Extensions
	{
		public static bool ObjectExists(this IAmazonS3 client, string bucket, string key)
		{
			var request = new GetObjectRequest {BucketName = bucket, Key = key};

			try
			{
				var response = client.GetObject(request);
				if (response.ResponseStream != null)
				{
					return true;
				}
			}
			catch (AmazonS3Exception)
			{
				return false;
			}
			catch (WebException)
			{
				return false;
			}
			catch (Exception)
			{
				return false;
			}
			return false;
		}

		public static bool ObjectExistsAndIsTheSame(this IAmazonS3 client, GetObjectMetadataRequest objectMetadataRequest, string metaDataFileHashKey, string fileMD5Hash)
		{
			try
			{
				var metadata = client.GetObjectMetadata(objectMetadataRequest);

				if (metadata != null)
				{					
					if (metadata.ETag != null && metadata.ETag == fileMD5Hash) return true;
				}
			}
			catch (AmazonS3Exception)
			{
				return false;
			}
			catch (WebException)
			{
				return false;
			}
			catch (Exception)
			{
				return false;
			}
			return false;
		}
	}