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  5. aws-sdk-net

Configure aws-sdk-net for R2

You must generate an Access Key before getting started. All examples will utilize access_key_id and access_key_secret variables which represent the Access Key ID and Secret Access Key values you generated.

This example uses version 3 of the aws-sdk-net package. You must pass in the R2 configuration credentials when instantiating your S3 service client:

​​ Client setup

In this example, you will pass credentials explicitly to the IAmazonS3 initialization. If you wish, use a shared AWS credentials file or the SDK store in-line with other AWS SDKs. Refer to Configure AWS credentials for more details.

private static IAmazonS3 s3Client;



public static void Main(string[] args)

{
	var accessKey = "<ACCESS_KEY>";
	var secretKey = "<SECRET_KEY>";
	var credentials = new BasicAWSCredentials(accessKey, secretKey);
	s3Client = new AmazonS3Client(credentials, new AmazonS3Config
		{
			ServiceURL = "https://<ACCOUNT_ID>.r2.cloudflarestorage.com",
		});

}

​​ List buckets and objects

The ListBucketsAsync and ListObjectsAsync methods can be used to list buckets under your account and the contents of those buckets respectively.

static async Task ListBuckets()

{
	var response = await s3Client.ListBucketsAsync();


	foreach (var s3Bucket in response.Buckets)
	{
		Console.WriteLine("{0}", s3Bucket.BucketName);
	}

}

// sdk-example

// my-bucket-name

static async Task ListObjectsV2()

{
	var request = new ListObjectsV2Request
	{
		BucketName = "sdk-example"
	};
            
	var response = await s3Client.ListObjectsV2Async(request);


	foreach (var s3Object in response.S3Objects)
	{
		Console.WriteLine("{0}", s3Object.Key);
	}

}

// dog.png

// cat.png

​​ Upload and retrieve objects

The PutObjectAsync and GetObjectAsync methods can be used to upload objects and download objects from an R2 bucket respectively.

static async Task PutObject()

{
	var request = new PutObjectRequest
	{
		FilePath = @"/path/file.txt",
		BucketName = "sdk-example",
		DisablePayloadSigning = true
	};
            
	var response = await s3Client.PutObjectAsync(request);
            
	Console.WriteLine("ETag: {0}", response.ETag);

}

// ETag: "186a71ee365d9686c3b98b6976e1f196"

static async Task GetObject()

{
  var bucket = "sdk-example";
  var key = "file.txt"
  
	var response = await s3Client.GetObjectAsync(bucket, key);


	Console.WriteLine("ETag: {0}", response.ETag);

}

// ETag: "186a71ee365d9686c3b98b6976e1f196"

​​ Generate presigned URLs

The GetPreSignedURL method allows you to sign ahead of time, giving temporary access to a specific operation. In this case, presigning a PutObject request for sdk-example/file.txt.

static string? GeneratePresignedUrl()

{
	AWSConfigsS3.UseSignatureVersion4 = true;
	var presign = new GetPreSignedUrlRequest
	{
		BucketName = "sdk-example",
		Key = "file.txt",
		Verb = HttpVerb.GET,
		Expires = DateTime.Now.AddDays(7),
	};
            
	var presignedUrl = s3Client.GetPreSignedURL(presign);
            
	Console.WriteLine(presignedUrl);
	
	return presignedUrl;

}

// URL: https://<accountid>.r2.cloudflarestorage.com/sdk-example/file.txt?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=<credential>&X-Amz-Date=<timestamp>&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=<signature>