Esempio n. 1
0
// CompleteMultipartUpload - complete a multipart upload and persist the data
func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	// check bucket name valid
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// verify object path legal
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	if !fs.isValidUploadID(object, uploadID) {
		return ObjectMetadata{}, probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, err := os.Stat(bucketPath); err != nil {
		// check bucket exists
		if os.IsNotExist(err) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(InternalError{})
	}

	objectPath := filepath.Join(bucketPath, object)
	file, err := atomic.FileCreateWithPrefix(objectPath, "")
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	h := md5.New()
	mw := io.MultiWriter(file, h)

	partBytes, err := ioutil.ReadAll(data)
	if err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(err)
	}
	if signature != nil {
		sh := sha256.New()
		sh.Write(partBytes)
		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if perr != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	parts := &CompleteMultipartUpload{}
	if err := xml.Unmarshal(partBytes, parts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(MalformedXML{})
	}
	if !sort.IsSorted(completedParts(parts.Part)) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPartOrder{})
	}

	if err := fs.concatParts(parts, objectPath, mw); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace()
	}

	delete(fs.multiparts.ActiveSession, object)
	for _, part := range parts.Part {
		err = os.Remove(objectPath + fmt.Sprintf("$%d-$multiparts", part.PartNumber))
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	}
	if err := os.Remove(objectPath + "$multiparts"); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(err)
	}
	if err := saveMultipartsSession(fs.multiparts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace()
	}
	file.Close()

	st, err := os.Stat(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: "application/octet-stream",
		Md5:         hex.EncodeToString(h.Sum(nil)),
	}
	return newObject, nil
}
Esempio n. 2
0
// CreateObjectPart - create a part in a multipart session
func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum string, partID int, size int64, data io.Reader, signature *Signature) (string, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	di, err := disk.GetInfo(fs.path)
	if err != nil {
		return "", probe.NewError(err)
	}

	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return "", probe.NewError(RootPathFull{Path: fs.path})
	}

	if partID <= 0 {
		return "", probe.NewError(errors.New("invalid part id, cannot be zero or less than zero"))
	}
	// check bucket name valid
	if !IsValidBucketName(bucket) {
		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// verify object path legal
	if !IsValidObjectName(object) {
		return "", probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	if !fs.isValidUploadID(object, uploadID) {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, err = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return "", probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, err = os.Stat(bucketPath); err != nil {
		// check bucket exists
		if os.IsNotExist(err) {
			return "", probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return "", probe.NewError(err)
	}

	objectPath := filepath.Join(bucketPath, object)
	partPath := objectPath + fmt.Sprintf("$%d-$multiparts", partID)
	partFile, err := atomic.FileCreateWithPrefix(partPath, "$multiparts")
	if err != nil {
		return "", probe.NewError(err)
	}
	h := md5.New()
	sh := sha256.New()
	mw := io.MultiWriter(partFile, h, sh)
	_, err = io.CopyN(mw, data, size)
	if err != nil {
		partFile.CloseAndPurge()
		return "", probe.NewError(err)
	}
	md5sum := hex.EncodeToString(h.Sum(nil))
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum); err != nil {
			partFile.CloseAndPurge()
			return "", probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	if signature != nil {
		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if perr != nil {
			partFile.CloseAndPurge()
			return "", perr.Trace()
		}
		if !ok {
			partFile.CloseAndPurge()
			return "", probe.NewError(SignatureDoesNotMatch{})
		}
	}
	partFile.Close()

	fi, err := os.Stat(partPath)
	if err != nil {
		return "", probe.NewError(err)
	}
	partMetadata := PartMetadata{}
	partMetadata.ETag = md5sum
	partMetadata.PartNumber = partID
	partMetadata.Size = fi.Size()
	partMetadata.LastModified = fi.ModTime()

	multiPartfile, err := os.OpenFile(objectPath+"$multiparts", os.O_RDWR|os.O_APPEND, 0600)
	if err != nil {
		return "", probe.NewError(err)
	}
	defer multiPartfile.Close()

	var deserializedMultipartSession MultipartSession
	decoder := json.NewDecoder(multiPartfile)
	err = decoder.Decode(&deserializedMultipartSession)
	if err != nil {
		return "", probe.NewError(err)
	}
	deserializedMultipartSession.Parts = append(deserializedMultipartSession.Parts, &partMetadata)
	deserializedMultipartSession.TotalParts++
	fs.multiparts.ActiveSession[object] = &deserializedMultipartSession

	sort.Sort(partNumber(deserializedMultipartSession.Parts))
	encoder := json.NewEncoder(multiPartfile)
	err = encoder.Encode(&deserializedMultipartSession)
	if err != nil {
		return "", probe.NewError(err)
	}
	return partMetadata.ETag, nil
}
Esempio n. 3
0
// CompleteMultipartUpload - complete a multipart upload and persist the data
func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	// Check bucket name is valid.
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// Verify object path is legal.
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Verify if valid upload for incoming object.
	if !fs.isValidUploadID(object, uploadID) {
		return ObjectMetadata{}, probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, e := os.Stat(bucketPath); e != nil {
		// Check bucket exists.
		if os.IsNotExist(e) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(InternalError{})
	}

	objectPath := filepath.Join(bucketPath, object)
	file, e := atomic.FileCreateWithPrefix(objectPath, "$tmpobject")
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}
	md5Hasher := md5.New()
	objectWriter := io.MultiWriter(file, md5Hasher)

	partBytes, e := ioutil.ReadAll(data)
	if e != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(e)
	}
	if signature != nil {
		sh := sha256.New()
		sh.Write(partBytes)
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, err.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	completeMultipartUpload := &CompleteMultipartUpload{}
	if e := xml.Unmarshal(partBytes, completeMultipartUpload); e != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(MalformedXML{})
	}
	if !sort.IsSorted(completedParts(completeMultipartUpload.Part)) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPartOrder{})
	}

	// Save parts for verification.
	parts := completeMultipartUpload.Part

	// Critical region requiring read lock.
	fs.rwLock.RLock()
	savedParts := fs.multiparts.ActiveSession[uploadID].Parts
	fs.rwLock.RUnlock()

	if !doPartsMatch(parts, savedParts) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPart{})
	}

	// Parts successfully validated, save all the parts.
	partPathPrefix := objectPath + uploadID
	if err := saveParts(partPathPrefix, objectWriter, parts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace(partPathPrefix)
	}
	// Successfully saved, remove all parts.
	removeParts(partPathPrefix, savedParts)

	// Critical region requiring write lock.
	fs.rwLock.Lock()
	delete(fs.multiparts.ActiveSession, uploadID)
	if err := saveMultipartsSession(*fs.multiparts); err != nil {
		fs.rwLock.Unlock()
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace(partPathPrefix)
	}
	file.Close()
	fs.rwLock.Unlock()

	// Send stat again to get object metadata.
	st, e := os.Stat(objectPath)
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}
	contentType := "application/octet-stream"
	if objectExt := filepath.Ext(objectPath); objectExt != "" {
		content, ok := mimedb.DB[strings.ToLower(strings.TrimPrefix(objectExt, "."))]
		if ok {
			contentType = content.ContentType
		}
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: contentType,
		MD5:         hex.EncodeToString(md5Hasher.Sum(nil)),
	}
	return newObject, nil
}
Esempio n. 4
0
// CreateObjectPart - create a part in a multipart session
func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum string, partID int, size int64, data io.Reader, signature *Signature) (string, *probe.Error) {
	di, err := disk.GetInfo(fs.path)
	if err != nil {
		return "", probe.NewError(err)
	}

	// Remove 5% from total space for cumulative disk space used for
	// journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return "", probe.NewError(RootPathFull{Path: fs.path})
	}

	// Part id cannot be negative.
	if partID <= 0 {
		return "", probe.NewError(errors.New("invalid part id, cannot be zero or less than zero"))
	}

	// Check bucket name valid.
	if !IsValidBucketName(bucket) {
		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// Verify object path legal.
	if !IsValidObjectName(object) {
		return "", probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Verify upload is valid for the incoming object.
	if !fs.isValidUploadID(object, uploadID) {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, err = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// Pro-actively close the connection
			return "", probe.NewError(InvalidDigest{MD5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, err = os.Stat(bucketPath); err != nil {
		// Check bucket exists.
		if os.IsNotExist(err) {
			return "", probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return "", probe.NewError(err)
	}

	objectPath := filepath.Join(bucketPath, object)
	partPathPrefix := objectPath + uploadID
	partPath := partPathPrefix + expectedMD5Sum + fmt.Sprintf("$%d-$multiparts", partID)
	partFile, e := atomic.FileCreateWithPrefix(partPath, "$multiparts")
	if e != nil {
		return "", probe.NewError(e)
	}

	md5Hasher := md5.New()
	sha256Hasher := sha256.New()
	partWriter := io.MultiWriter(partFile, md5Hasher, sha256Hasher)
	if _, e = io.CopyN(partWriter, data, size); e != nil {
		partFile.CloseAndPurge()
		return "", probe.NewError(e)
	}

	md5sum := hex.EncodeToString(md5Hasher.Sum(nil))
	// Verify if the written object is equal to what is expected, only
	// if it is requested as such.
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum) {
			partFile.CloseAndPurge()
			return "", probe.NewError(BadDigest{MD5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sha256Hasher.Sum(nil)))
		if err != nil {
			partFile.CloseAndPurge()
			return "", err.Trace()
		}
		if !ok {
			partFile.CloseAndPurge()
			return "", probe.NewError(SignatureDoesNotMatch{})
		}
	}
	partFile.Close()

	fi, e := os.Stat(partPath)
	if e != nil {
		return "", probe.NewError(e)
	}
	partMetadata := PartMetadata{}
	partMetadata.ETag = md5sum
	partMetadata.PartNumber = partID
	partMetadata.Size = fi.Size()
	partMetadata.LastModified = fi.ModTime()

	// Critical region requiring read lock.
	fs.rwLock.RLock()
	deserializedMultipartSession, ok := fs.multiparts.ActiveSession[uploadID]
	fs.rwLock.RUnlock()
	if !ok {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	// Append any pre-existing partNumber with new metadata, otherwise
	// append to the list.
	if len(deserializedMultipartSession.Parts) < partID {
		deserializedMultipartSession.Parts = append(deserializedMultipartSession.Parts, partMetadata)
	} else {
		deserializedMultipartSession.Parts[partID-1] = partMetadata
	}
	deserializedMultipartSession.TotalParts = len(deserializedMultipartSession.Parts)
	// Sort by part number before saving.
	sort.Sort(partNumber(deserializedMultipartSession.Parts))

	// Critical region requiring write lock.
	fs.rwLock.Lock()
	fs.multiparts.ActiveSession[uploadID] = deserializedMultipartSession
	if err := saveMultipartsSession(*fs.multiparts); err != nil {
		fs.rwLock.Unlock()
		return "", err.Trace(partPathPrefix)
	}
	fs.rwLock.Unlock()

	// Return etag.
	return partMetadata.ETag, nil
}
Esempio n. 5
0
// CreateObject - PUT object
func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	di, err := disk.GetInfo(fs.path)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}

	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return ObjectMetadata{}, probe.NewError(RootPathFull{Path: fs.path})
	}

	// check bucket name valid
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, e := os.Stat(bucketPath); e != nil {
		if os.IsNotExist(e) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(e)
	}
	// verify object path legal
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// get object path
	objectPath := filepath.Join(bucketPath, object)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, err = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return ObjectMetadata{}, probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// write object
	file, err := atomic.FileCreateWithPrefix(objectPath, "")
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}

	h := md5.New()
	sh := sha256.New()
	mw := io.MultiWriter(file, h, sh)

	if size > 0 {
		_, err = io.CopyN(mw, data, size)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	} else {
		_, err = io.Copy(mw, data)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	}

	md5Sum := hex.EncodeToString(h.Sum(nil))
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	sha256Sum := hex.EncodeToString(sh.Sum(nil))
	if signature != nil {
		ok, perr := signature.DoesSignatureMatch(sha256Sum)
		if perr != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, perr.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	file.Close()

	st, err := os.Stat(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: "application/octet-stream",
		Md5:         md5Sum,
	}
	return newObject, nil
}
Esempio n. 6
0
// CreateObject - create an object.
func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	di, e := disk.GetInfo(fs.path)
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}

	// Remove 5% from total space for cumulative disk space used for
	// journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return ObjectMetadata{}, probe.NewError(RootPathFull{Path: fs.path})
	}

	// Check bucket name valid.
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, e = os.Stat(bucketPath); e != nil {
		if os.IsNotExist(e) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(e)
	}

	// Verify object path legal.
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Get object path.
	objectPath := filepath.Join(bucketPath, object)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, e = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if e != nil {
			// Pro-actively close the connection.
			return ObjectMetadata{}, probe.NewError(InvalidDigest{MD5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// Write object.
	file, e := atomic.FileCreateWithPrefix(objectPath, "$tmpobject")
	if e != nil {
		switch e := e.(type) {
		case *os.PathError:
			if e.Op == "mkdir" {
				if strings.Contains(e.Error(), "not a directory") {
					return ObjectMetadata{}, probe.NewError(ObjectExistsAsPrefix{Bucket: bucket, Prefix: object})
				}
			}
			return ObjectMetadata{}, probe.NewError(e)
		default:
			return ObjectMetadata{}, probe.NewError(e)
		}
	}

	// Instantiate checksum hashers and create a multiwriter.
	md5Hasher := md5.New()
	sha256Hasher := sha256.New()
	objectWriter := io.MultiWriter(file, md5Hasher, sha256Hasher)

	if size > 0 {
		if _, e = io.CopyN(objectWriter, data, size); e != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(e)
		}
	} else {
		if _, e = io.Copy(objectWriter, data); e != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(e)
		}
	}

	md5Sum := hex.EncodeToString(md5Hasher.Sum(nil))
	// Verify if the written object is equal to what is expected, only
	// if it is requested as such.
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum) {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(BadDigest{MD5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	sha256Sum := hex.EncodeToString(sha256Hasher.Sum(nil))
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(sha256Sum)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, err.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	file.Close()

	// Set stat again to get the latest metadata.

	st, e := os.Stat(objectPath)
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}
	e = fs.checksyncstatus(objectPath)
	if e != nil {
		fmt.Println(e)
		return ObjectMetadata{}, probe.NewError(e)
	}
	contentType := "application/octet-stream"
	if objectExt := filepath.Ext(objectPath); objectExt != "" {
		content, ok := mimedb.DB[strings.ToLower(strings.TrimPrefix(objectExt, "."))]
		if ok {
			contentType = content.ContentType
		}
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: contentType,
		MD5:         md5Sum,
	}
	return newObject, nil
}