feat: adds x-amz-object-size in PutObject response headers

Closes #1518

Adds the `x-amz-object-size` header to the `PutObject` response, indicating the size of the uploaded object. This change is applied to the POSIX, Azure, and S3 proxy backends.

backend/azure/azure.go

@@ -367,6 +367,7 @@ func (az *Azure) PutObject(ctx context.Context, po s3response.PutObjectInput) (s
 
 	return s3response.PutObjectOutput{
 		ETag: convertAzureEtag(uploadResp.ETag),
+		Size: po.ContentLength,
 	}, nil
 }
 

backend/posix/posix.go

@@ -2796,6 +2796,7 @@ func (p *Posix) PutObject(ctx context.Context, po s3response.PutObjectInput) (s3
 		// for directory object no version is created
 		return s3response.PutObjectOutput{
 			ETag: emptyMD5,
+			Size: &contentLength,
 		}, nil
 	}
 
@@ -2848,6 +2849,8 @@ func (p *Posix) PutObject(ctx context.Context, po s3response.PutObjectInput) (s3
 	}
 	defer f.cleanup()
 
+	objsize := f.size
+
 	hash := md5.New()
 	rdr := io.TeeReader(po.Body, hash)
 
@@ -2984,7 +2987,6 @@ func (p *Posix) PutObject(ctx context.Context, po s3response.PutObjectInput) (s3
 			return s3response.PutObjectOutput{}, fmt.Errorf("set versionId attr: %w", err)
 		}
 	}
-
 	err = f.link()
 	if errors.Is(err, syscall.EEXIST) {
 		return s3response.PutObjectOutput{
@@ -3042,6 +3044,7 @@ func (p *Posix) PutObject(ctx context.Context, po s3response.PutObjectInput) (s3
 		ChecksumSHA1:      checksum.SHA1,
 		ChecksumSHA256:    checksum.SHA256,
 		ChecksumCRC64NVME: checksum.CRC64NVME,
+		Size:              &objsize,
 		ChecksumType:      checksum.Type,
 	}, nil
 }

backend/s3proxy/s3.go

@@ -938,6 +938,7 @@ func (s *S3Proxy) PutObject(ctx context.Context, input s3response.PutObjectInput
 		ChecksumCRC64NVME: output.ChecksumCRC64NVME,
 		ChecksumSHA1:      output.ChecksumSHA1,
 		ChecksumSHA256:    output.ChecksumSHA256,
+		Size:              output.Size,
 	}, nil
 }
 

s3api/controllers/object-put.go

@@ -725,6 +725,7 @@ func (c S3ApiController) PutObject(ctx *fiber.Ctx) (*Response, error) {
 			"x-amz-checksum-sha256":    res.ChecksumSHA256,
 			"x-amz-checksum-type":      utils.ConvertToStringPtr(res.ChecksumType),
 			"x-amz-version-id":         &res.VersionID,
+			"x-amz-object-size":        utils.ConvertPtrToStringPtr(res.Size),
 		},
 		MetaOpts: &MetaOptions{
 			ContentLength: contentLength,

s3api/controllers/object-put_test.go

@@ -1036,6 +1036,7 @@ func TestS3ApiController_CopyObject(t *testing.T) {
 func TestS3ApiController_PutObject(t *testing.T) {
 	str := ""
 	emptyStringPtr := &str
+	objSize := int64(120)
 
 	tests := []struct {
 		name   string
@@ -1148,6 +1149,7 @@ func TestS3ApiController_PutObject(t *testing.T) {
 						"x-amz-checksum-sha256":    nil,
 						"x-amz-checksum-type":      nil,
 						"x-amz-version-id":         emptyStringPtr,
+						"x-amz-object-size":        nil,
 					},
 					MetaOpts: &MetaOptions{
 						BucketOwner:   "root",
@@ -1188,6 +1190,7 @@ func TestS3ApiController_PutObject(t *testing.T) {
 					ChecksumCRC64NVME: utils.GetStringPtr("crc64nvme"),
 					ChecksumType:      types.ChecksumTypeComposite,
 					VersionID:         "versionId",
+					Size:              &objSize,
 				},
 			},
 			output: testOutput{
@@ -1201,6 +1204,7 @@ func TestS3ApiController_PutObject(t *testing.T) {
 						"x-amz-checksum-sha256":    utils.GetStringPtr("sha256"),
 						"x-amz-checksum-type":      utils.GetStringPtr(string(types.ChecksumTypeComposite)),
 						"x-amz-version-id":         utils.GetStringPtr("versionId"),
+						"x-amz-object-size":        utils.ConvertToStringPtr(objSize),
 					},
 					MetaOpts: &MetaOptions{
 						BucketOwner:   "root",

s3response/s3response.go

@@ -37,6 +37,7 @@ type PutObjectOutput struct {
 	ChecksumSHA1      *string
 	ChecksumSHA256    *string
 	ChecksumCRC64NVME *string
+	Size              *int64
 	ChecksumType      types.ChecksumType
 }
 

tests/integration/tests.go

@@ -3418,10 +3418,33 @@ func PutObject_racey_success(s *S3Conf) error {
 func PutObject_success(s *S3Conf) error {
 	testName := "PutObject_success"
 	return actionHandler(s, testName, func(s3client *s3.Client, bucket string) error {
-		_, err := putObjects(s3client, []string{"my-obj"}, bucket)
+		lgth := int64(100)
+		res, err := putObjectWithData(lgth, &s3.PutObjectInput{
+			Bucket: &bucket,
+			Key:    getPtr("my-obj"),
+		}, s3client)
 		if err != nil {
 			return err
 		}
+
+		// skip the ETag check for azure tests
+		if !s.azureTests {
+			etag, err := calculateEtag(res.data)
+			if err != nil {
+				return err
+			}
+
+			if getString(res.res.ETag) != etag {
+				return fmt.Errorf("expected ETag to be %s, intead got %s", getString(res.res.ETag), etag)
+			}
+		}
+		if res.res.Size == nil {
+			return fmt.Errorf("unexpected nil object Size")
+		}
+		if *res.res.Size != lgth {
+			return fmt.Errorf("expected the object size to be %v, instead got %v", lgth, *res.res.Size)
+		}
+
 		return nil
 	})
 }

tests/integration/utils.go

@@ -17,6 +17,7 @@ package integration
 import (
 	"bytes"
 	"context"
+	"crypto/md5"
 	"crypto/rand"
 	"crypto/sha1"
 	"crypto/sha256"
@@ -1798,3 +1799,13 @@ func testOPTIONSEdnpoint(s *S3Conf, bucket, origin, method string, headers strin
 
 	return comparePreflightResult(expected, result)
 }
+
+func calculateEtag(data []byte) (string, error) {
+	h := md5.New()
+	_, err := h.Write(data)
+	if err != nil {
+		return "", err
+	}
+	dataSum := h.Sum(nil)
+	return fmt.Sprintf("\"%s\"", hex.EncodeToString(dataSum[:])), nil
+}