S3

Object storage emulation.

Partial Support

Supported Operations

Operation	Status	Notes
CreateBucket	Supported	Path-style; honours LocationConstraint and signing region
DeleteBucket	Supported	Must be empty
ListBuckets	Supported
HeadBucket	Supported	Returns x-amz-bucket-region header
PutObject	Supported	Basic put, no server-side encryption
GetObject	Supported
DeleteObject	Supported
ListObjects	Supported
CopyObject	Supported	Handles non-ASCII keys
HeadObject	Supported
CreateMultipartUpload	Supported	Multipart upload initiation
UploadPart	Supported	Upload individual parts
CompleteMultipartUpload	Supported	Assemble uploaded parts
AbortMultipartUpload	Supported	Discard an in-progress upload
PutBucketNotificationConfiguration	Supported	Lambda notifications only
GetBucketNotificationConfiguration	Supported	Lambda notifications only

Examples

Using AWS SDK

JavaScript

import { S3Client, CreateBucketCommand, PutObjectCommand, GetObjectCommand } from "@aws-sdk/client-s3";

const s3 = new S3Client({
  endpoint: "http://127.0.0.1:4566",
  region: "us-east-1",
  credentials: { accessKeyId: "test", secretAccessKey: "test" }
});

// Create bucket
await s3.send(new CreateBucketCommand({ Bucket: "my-bucket" }));

// Put object
await s3.send(new PutObjectCommand({
  Bucket: "my-bucket",
  Key: "file.txt",
  Body: "Hello World"
}));

// Get object
const obj = await s3.send(new GetObjectCommand({
  Bucket: "my-bucket",
  Key: "file.txt"
}));

console.log(await obj.Body?.transformToString());

Access URL Format

S3 objects in Tarn use path-style URLs:

http://127.0.0.1:4566/_s3/{bucket}/{key}

Example:

curl http://127.0.0.1:4566/_s3/my-bucket/file.txt

Additional Features

• Multipart uploads
• Bucket notification configuration for Lambda targets
• Prefix and suffix filters on Lambda bucket notifications
• CreateBucket parses LocationConstraint from the request body and rejects explicit us-east-1 (matching real AWS behaviour). When no body is sent, the signing region from the Authorization header is used.
• HeadBucket returns the stored region in the x-amz-bucket-region response header
• GetBucketLocation returns the region the bucket was created in

Known Limitations

• Path-style only (no virtual-hosted style: bucket.s3.amazonaws.com)
• No versioning
• No lifecycle policies
• No server-side encryption
• No bucket policies or ACLs
• Bucket notifications support Lambda targets only