IAmazonS3.PutObjectAsync (PutObjectRequest, CancellationToken)

Method

End of support notice: Beginning October 1, 2025, Amazon S3 will discontinue support for creating new Email Grantee Access Control Lists (ACL). Email Grantee ACLs created prior to this date will continue to work and remain accessible through the Amazon Web Services Management Console, Command Line Interface (CLI), SDKs, and REST API. However, you will no longer be able to create new Email Grantee ACLs.

This change affects the following Amazon Web Services Regions: US East (N. Virginia) Region, US West (N. California) Region, US West (Oregon) Region, Asia Pacific (Singapore) Region, Asia Pacific (Sydney) Region, Asia Pacific (Tokyo) Region, Europe (Ireland) Region, and South America (São Paulo) Region.

Adds an object to a bucket.

Amazon S3 is a distributed system. If it receives multiple write requests for the same object simultaneously, it overwrites all but the last object written. However, Amazon S3 provides features that can modify this behavior:

• S3 Object Lock - To prevent objects from being deleted or overwritten, you can use Amazon S3 Object Lock in the Amazon S3 User Guide.

  This functionality is not supported for directory buckets.

• If-None-Match - Uploads the object only if the object key name does not already exist in the specified bucket. Otherwise, Amazon S3 returns a 412 Precondition Failed error. If a conflicting operation occurs during the upload, S3 returns a 409 ConditionalRequestConflict response. On a 409 failure, retry the upload.

  Expects the * character (asterisk).

  For more information, see Add preconditions to S3 operations with conditional requests in the Amazon S3 User Guide or RFC 7232.

  This functionality is not supported for S3 on Outposts.

• S3 Versioning - When you enable versioning for a bucket, if Amazon S3 receives multiple write requests for the same object simultaneously, it stores all versions of the objects. For each write request that is made to the same object, Amazon S3 automatically generates a unique version ID of that object being stored in Amazon S3. You can retrieve, replace, or delete any version of the object. For more information about versioning, see Adding Objects to Versioning-Enabled Buckets in the Amazon S3 User Guide. For information about returning the versioning state of a bucket, see GetBucketVersioning.

  This functionality is not supported for directory buckets.

Permissions

• General purpose bucket permissions - The following permissions are required in your policies when your PutObject request includes specific headers.

  • s3:PutObject - To successfully complete the PutObject request, you must always have the s3:PutObject permission on a bucket to add an object to it.

  • s3:PutObjectAcl - To successfully change the objects ACL of your PutObject request, you must have the s3:PutObjectAcl.

  • s3:PutObjectTagging - To successfully set the tag-set with your PutObject request, you must have the s3:PutObjectTagging.

• Directory bucket permissions - To grant access to this API operation on a directory bucket, we recommend that you use the CreateSession API operation for session-based authorization. Specifically, you grant the s3express:CreateSession permission to the directory bucket in a bucket policy or an IAM identity-based policy. Then, you make the CreateSession API call on the bucket to obtain a session token. With the session token in your request header, you can make API requests to this operation. After the session token expires, you make another CreateSession API call to generate a new session token for use. Amazon Web Services CLI or SDKs create session and refresh the session token automatically to avoid service interruptions when a session expires. For more information about authorization, see CreateSession.

  If the object is encrypted with SSE-KMS, you must also have the kms:GenerateDataKey and kms:Decrypt permissions in IAM identity-based policies and KMS key policies for the KMS key.

Data integrity with Content-MD5

• General purpose bucket - To ensure that data is not corrupted traversing the network, use the Content-MD5 header. When you use this header, Amazon S3 checks the object against the provided MD5 value and, if they do not match, Amazon S3 returns an error. Alternatively, when the object's ETag is its MD5 digest, you can calculate the MD5 while putting the object to Amazon S3 and compare the returned ETag to the calculated MD5 value.

• Directory bucket - This functionality is not supported for directory buckets.

HTTP Host header syntax

Directory buckets - The HTTP Host header syntax is Bucket-name.s3express-zone-id.region-code.amazonaws.com.

For more information about related Amazon S3 APIs, see the following:

• CopyObject

• DeleteObject

Namespace: Amazon.S3
Assembly: AWSSDK.S3.dll
Version: 3.x.y.z