Vendor dependencies for azure backend

vendor/github.com/Azure/azure-sdk-for-go/storage/blob.go

@@ -0,0 +1,629 @@
+package storage
+
+import (
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// A Blob is an entry in BlobListResponse.
+type Blob struct {
+	Container  *Container
+	Name       string         `xml:"Name"`
+	Snapshot   time.Time      `xml:"Snapshot"`
+	Properties BlobProperties `xml:"Properties"`
+	Metadata   BlobMetadata   `xml:"Metadata"`
+}
+
+// PutBlobOptions includes the options any put blob operation
+// (page, block, append)
+type PutBlobOptions struct {
+	Timeout           uint
+	LeaseID           string     `header:"x-ms-lease-id"`
+	Origin            string     `header:"Origin"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// BlobMetadata is a set of custom name/value pairs.
+//
+// See https://msdn.microsoft.com/en-us/library/azure/dd179404.aspx
+type BlobMetadata map[string]string
+
+type blobMetadataEntries struct {
+	Entries []blobMetadataEntry `xml:",any"`
+}
+type blobMetadataEntry struct {
+	XMLName xml.Name
+	Value   string `xml:",chardata"`
+}
+
+// UnmarshalXML converts the xml:Metadata into Metadata map
+func (bm *BlobMetadata) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	var entries blobMetadataEntries
+	if err := d.DecodeElement(&entries, &start); err != nil {
+		return err
+	}
+	for _, entry := range entries.Entries {
+		if *bm == nil {
+			*bm = make(BlobMetadata)
+		}
+		(*bm)[strings.ToLower(entry.XMLName.Local)] = entry.Value
+	}
+	return nil
+}
+
+// MarshalXML implements the xml.Marshaler interface. It encodes
+// metadata name/value pairs as they would appear in an Azure
+// ListBlobs response.
+func (bm BlobMetadata) MarshalXML(enc *xml.Encoder, start xml.StartElement) error {
+	entries := make([]blobMetadataEntry, 0, len(bm))
+	for k, v := range bm {
+		entries = append(entries, blobMetadataEntry{
+			XMLName: xml.Name{Local: http.CanonicalHeaderKey(k)},
+			Value:   v,
+		})
+	}
+	return enc.EncodeElement(blobMetadataEntries{
+		Entries: entries,
+	}, start)
+}
+
+// BlobProperties contains various properties of a blob
+// returned in various endpoints like ListBlobs or GetBlobProperties.
+type BlobProperties struct {
+	LastModified          TimeRFC1123 `xml:"Last-Modified"`
+	Etag                  string      `xml:"Etag"`
+	ContentMD5            string      `xml:"Content-MD5" header:"x-ms-blob-content-md5"`
+	ContentLength         int64       `xml:"Content-Length"`
+	ContentType           string      `xml:"Content-Type" header:"x-ms-blob-content-type"`
+	ContentEncoding       string      `xml:"Content-Encoding" header:"x-ms-blob-content-encoding"`
+	CacheControl          string      `xml:"Cache-Control" header:"x-ms-blob-cache-control"`
+	ContentLanguage       string      `xml:"Cache-Language" header:"x-ms-blob-content-language"`
+	ContentDisposition    string      `xml:"Content-Disposition" header:"x-ms-blob-content-disposition"`
+	BlobType              BlobType    `xml:"x-ms-blob-blob-type"`
+	SequenceNumber        int64       `xml:"x-ms-blob-sequence-number"`
+	CopyID                string      `xml:"CopyId"`
+	CopyStatus            string      `xml:"CopyStatus"`
+	CopySource            string      `xml:"CopySource"`
+	CopyProgress          string      `xml:"CopyProgress"`
+	CopyCompletionTime    TimeRFC1123 `xml:"CopyCompletionTime"`
+	CopyStatusDescription string      `xml:"CopyStatusDescription"`
+	LeaseStatus           string      `xml:"LeaseStatus"`
+	LeaseState            string      `xml:"LeaseState"`
+	LeaseDuration         string      `xml:"LeaseDuration"`
+	ServerEncrypted       bool        `xml:"ServerEncrypted"`
+	IncrementalCopy       bool        `xml:"IncrementalCopy"`
+}
+
+// BlobType defines the type of the Azure Blob.
+type BlobType string
+
+// Types of page blobs
+const (
+	BlobTypeBlock  BlobType = "BlockBlob"
+	BlobTypePage   BlobType = "PageBlob"
+	BlobTypeAppend BlobType = "AppendBlob"
+)
+
+func (b *Blob) buildPath() string {
+	return b.Container.buildPath() + "/" + b.Name
+}
+
+// Exists returns true if a blob with given name exists on the specified
+// container of the storage account.
+func (b *Blob) Exists() (bool, error) {
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), nil)
+	headers := b.Container.bsc.client.getStandardHeaders()
+	resp, err := b.Container.bsc.client.exec(http.MethodHead, uri, headers, nil, b.Container.bsc.auth)
+	if resp != nil {
+		defer readAndCloseBody(resp.body)
+		if resp.statusCode == http.StatusOK || resp.statusCode == http.StatusNotFound {
+			return resp.statusCode == http.StatusOK, nil
+		}
+	}
+	return false, err
+}
+
+// GetURL gets the canonical URL to the blob with the specified name in the
+// specified container. If name is not specified, the canonical URL for the entire
+// container is obtained.
+// This method does not create a publicly accessible URL if the blob or container
+// is private and this method does not check if the blob exists.
+func (b *Blob) GetURL() string {
+	container := b.Container.Name
+	if container == "" {
+		container = "$root"
+	}
+	return b.Container.bsc.client.getEndpoint(blobServiceName, pathForResource(container, b.Name), nil)
+}
+
+// GetBlobRangeOptions includes the options for a get blob range operation
+type GetBlobRangeOptions struct {
+	Range              *BlobRange
+	GetRangeContentMD5 bool
+	*GetBlobOptions
+}
+
+// GetBlobOptions includes the options for a get blob operation
+type GetBlobOptions struct {
+	Timeout           uint
+	Snapshot          *time.Time
+	LeaseID           string     `header:"x-ms-lease-id"`
+	Origin            string     `header:"Origin"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// BlobRange represents the bytes range to be get
+type BlobRange struct {
+	Start uint64
+	End   uint64
+}
+
+func (br BlobRange) String() string {
+	if br.End == 0 {
+		return fmt.Sprintf("bytes=%d-", br.Start)
+	}
+	return fmt.Sprintf("bytes=%d-%d", br.Start, br.End)
+}
+
+// Get returns a stream to read the blob. Caller must call both Read and Close()
+// to correctly close the underlying connection.
+//
+// See the GetRange method for use with a Range header.
+//
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Get-Blob
+func (b *Blob) Get(options *GetBlobOptions) (io.ReadCloser, error) {
+	rangeOptions := GetBlobRangeOptions{
+		GetBlobOptions: options,
+	}
+	resp, err := b.getRange(&rangeOptions)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := checkRespCode(resp.statusCode, []int{http.StatusOK}); err != nil {
+		return nil, err
+	}
+	if err := b.writeProperties(resp.headers, true); err != nil {
+		return resp.body, err
+	}
+	return resp.body, nil
+}
+
+// GetRange reads the specified range of a blob to a stream. The bytesRange
+// string must be in a format like "0-", "10-100" as defined in HTTP 1.1 spec.
+// Caller must call both Read and Close()// to correctly close the underlying
+// connection.
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Get-Blob
+func (b *Blob) GetRange(options *GetBlobRangeOptions) (io.ReadCloser, error) {
+	resp, err := b.getRange(options)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := checkRespCode(resp.statusCode, []int{http.StatusPartialContent}); err != nil {
+		return nil, err
+	}
+	// Content-Length header should not be updated, as the service returns the range length
+	// (which is not alwys the full blob length)
+	if err := b.writeProperties(resp.headers, false); err != nil {
+		return resp.body, err
+	}
+	return resp.body, nil
+}
+
+func (b *Blob) getRange(options *GetBlobRangeOptions) (*storageResponse, error) {
+	params := url.Values{}
+	headers := b.Container.bsc.client.getStandardHeaders()
+
+	if options != nil {
+		if options.Range != nil {
+			headers["Range"] = options.Range.String()
+			if options.GetRangeContentMD5 {
+				headers["x-ms-range-get-content-md5"] = "true"
+			}
+		}
+		if options.GetBlobOptions != nil {
+			headers = mergeHeaders(headers, headersFromStruct(*options.GetBlobOptions))
+			params = addTimeout(params, options.Timeout)
+			params = addSnapshot(params, options.Snapshot)
+		}
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	resp, err := b.Container.bsc.client.exec(http.MethodGet, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil {
+		return nil, err
+	}
+	return resp, err
+}
+
+// SnapshotOptions includes the options for a snapshot blob operation
+type SnapshotOptions struct {
+	Timeout           uint
+	LeaseID           string     `header:"x-ms-lease-id"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// CreateSnapshot creates a snapshot for a blob
+// See https://msdn.microsoft.com/en-us/library/azure/ee691971.aspx
+func (b *Blob) CreateSnapshot(options *SnapshotOptions) (snapshotTimestamp *time.Time, err error) {
+	params := url.Values{"comp": {"snapshot"}}
+	headers := b.Container.bsc.client.getStandardHeaders()
+	headers = b.Container.bsc.client.addMetadataToHeaders(headers, b.Metadata)
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	resp, err := b.Container.bsc.client.exec(http.MethodPut, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil || resp == nil {
+		return nil, err
+	}
+	defer readAndCloseBody(resp.body)
+
+	if err := checkRespCode(resp.statusCode, []int{http.StatusCreated}); err != nil {
+		return nil, err
+	}
+
+	snapshotResponse := resp.headers.Get(http.CanonicalHeaderKey("x-ms-snapshot"))
+	if snapshotResponse != "" {
+		snapshotTimestamp, err := time.Parse(time.RFC3339, snapshotResponse)
+		if err != nil {
+			return nil, err
+		}
+		return &snapshotTimestamp, nil
+	}
+
+	return nil, errors.New("Snapshot not created")
+}
+
+// GetBlobPropertiesOptions includes the options for a get blob properties operation
+type GetBlobPropertiesOptions struct {
+	Timeout           uint
+	Snapshot          *time.Time
+	LeaseID           string     `header:"x-ms-lease-id"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// GetProperties provides various information about the specified blob.
+// See https://msdn.microsoft.com/en-us/library/azure/dd179394.aspx
+func (b *Blob) GetProperties(options *GetBlobPropertiesOptions) error {
+	params := url.Values{}
+	headers := b.Container.bsc.client.getStandardHeaders()
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		params = addSnapshot(params, options.Snapshot)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	resp, err := b.Container.bsc.client.exec(http.MethodHead, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil {
+		return err
+	}
+	defer readAndCloseBody(resp.body)
+
+	if err = checkRespCode(resp.statusCode, []int{http.StatusOK}); err != nil {
+		return err
+	}
+	return b.writeProperties(resp.headers, true)
+}
+
+func (b *Blob) writeProperties(h http.Header, includeContentLen bool) error {
+	var err error
+
+	contentLength := b.Properties.ContentLength
+	if includeContentLen {
+		contentLengthStr := h.Get("Content-Length")
+		if contentLengthStr != "" {
+			contentLength, err = strconv.ParseInt(contentLengthStr, 0, 64)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	var sequenceNum int64
+	sequenceNumStr := h.Get("x-ms-blob-sequence-number")
+	if sequenceNumStr != "" {
+		sequenceNum, err = strconv.ParseInt(sequenceNumStr, 0, 64)
+		if err != nil {
+			return err
+		}
+	}
+
+	lastModified, err := getTimeFromHeaders(h, "Last-Modified")
+	if err != nil {
+		return err
+	}
+
+	copyCompletionTime, err := getTimeFromHeaders(h, "x-ms-copy-completion-time")
+	if err != nil {
+		return err
+	}
+
+	b.Properties = BlobProperties{
+		LastModified:          TimeRFC1123(*lastModified),
+		Etag:                  h.Get("Etag"),
+		ContentMD5:            h.Get("Content-MD5"),
+		ContentLength:         contentLength,
+		ContentEncoding:       h.Get("Content-Encoding"),
+		ContentType:           h.Get("Content-Type"),
+		ContentDisposition:    h.Get("Content-Disposition"),
+		CacheControl:          h.Get("Cache-Control"),
+		ContentLanguage:       h.Get("Content-Language"),
+		SequenceNumber:        sequenceNum,
+		CopyCompletionTime:    TimeRFC1123(*copyCompletionTime),
+		CopyStatusDescription: h.Get("x-ms-copy-status-description"),
+		CopyID:                h.Get("x-ms-copy-id"),
+		CopyProgress:          h.Get("x-ms-copy-progress"),
+		CopySource:            h.Get("x-ms-copy-source"),
+		CopyStatus:            h.Get("x-ms-copy-status"),
+		BlobType:              BlobType(h.Get("x-ms-blob-type")),
+		LeaseStatus:           h.Get("x-ms-lease-status"),
+		LeaseState:            h.Get("x-ms-lease-state"),
+	}
+	b.writeMetadata(h)
+	return nil
+}
+
+// SetBlobPropertiesOptions contains various properties of a blob and is an entry
+// in SetProperties
+type SetBlobPropertiesOptions struct {
+	Timeout              uint
+	LeaseID              string     `header:"x-ms-lease-id"`
+	Origin               string     `header:"Origin"`
+	IfModifiedSince      *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince    *time.Time `header:"If-Unmodified-Since"`
+	IfMatch              string     `header:"If-Match"`
+	IfNoneMatch          string     `header:"If-None-Match"`
+	SequenceNumberAction *SequenceNumberAction
+	RequestID            string `header:"x-ms-client-request-id"`
+}
+
+// SequenceNumberAction defines how the blob's sequence number should be modified
+type SequenceNumberAction string
+
+// Options for sequence number action
+const (
+	SequenceNumberActionMax       SequenceNumberAction = "max"
+	SequenceNumberActionUpdate    SequenceNumberAction = "update"
+	SequenceNumberActionIncrement SequenceNumberAction = "increment"
+)
+
+// SetProperties replaces the BlobHeaders for the specified blob.
+//
+// Some keys may be converted to Camel-Case before sending. All keys
+// are returned in lower case by GetBlobProperties. HTTP header names
+// are case-insensitive so case munging should not matter to other
+// applications either.
+//
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Set-Blob-Properties
+func (b *Blob) SetProperties(options *SetBlobPropertiesOptions) error {
+	params := url.Values{"comp": {"properties"}}
+	headers := b.Container.bsc.client.getStandardHeaders()
+	headers = mergeHeaders(headers, headersFromStruct(b.Properties))
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	if b.Properties.BlobType == BlobTypePage {
+		headers = addToHeaders(headers, "x-ms-blob-content-length", fmt.Sprintf("byte %v", b.Properties.ContentLength))
+		if options != nil || options.SequenceNumberAction != nil {
+			headers = addToHeaders(headers, "x-ms-sequence-number-action", string(*options.SequenceNumberAction))
+			if *options.SequenceNumberAction != SequenceNumberActionIncrement {
+				headers = addToHeaders(headers, "x-ms-blob-sequence-number", fmt.Sprintf("%v", b.Properties.SequenceNumber))
+			}
+		}
+	}
+
+	resp, err := b.Container.bsc.client.exec(http.MethodPut, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil {
+		return err
+	}
+	readAndCloseBody(resp.body)
+	return checkRespCode(resp.statusCode, []int{http.StatusOK})
+}
+
+// SetBlobMetadataOptions includes the options for a set blob metadata operation
+type SetBlobMetadataOptions struct {
+	Timeout           uint
+	LeaseID           string     `header:"x-ms-lease-id"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// SetMetadata replaces the metadata for the specified blob.
+//
+// Some keys may be converted to Camel-Case before sending. All keys
+// are returned in lower case by GetBlobMetadata. HTTP header names
+// are case-insensitive so case munging should not matter to other
+// applications either.
+//
+// See https://msdn.microsoft.com/en-us/library/azure/dd179414.aspx
+func (b *Blob) SetMetadata(options *SetBlobMetadataOptions) error {
+	params := url.Values{"comp": {"metadata"}}
+	headers := b.Container.bsc.client.getStandardHeaders()
+	headers = b.Container.bsc.client.addMetadataToHeaders(headers, b.Metadata)
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	resp, err := b.Container.bsc.client.exec(http.MethodPut, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil {
+		return err
+	}
+	readAndCloseBody(resp.body)
+	return checkRespCode(resp.statusCode, []int{http.StatusOK})
+}
+
+// GetBlobMetadataOptions includes the options for a get blob metadata operation
+type GetBlobMetadataOptions struct {
+	Timeout           uint
+	Snapshot          *time.Time
+	LeaseID           string     `header:"x-ms-lease-id"`
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// GetMetadata returns all user-defined metadata for the specified blob.
+//
+// All metadata keys will be returned in lower case. (HTTP header
+// names are case-insensitive.)
+//
+// See https://msdn.microsoft.com/en-us/library/azure/dd179414.aspx
+func (b *Blob) GetMetadata(options *GetBlobMetadataOptions) error {
+	params := url.Values{"comp": {"metadata"}}
+	headers := b.Container.bsc.client.getStandardHeaders()
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		params = addSnapshot(params, options.Snapshot)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+
+	resp, err := b.Container.bsc.client.exec(http.MethodGet, uri, headers, nil, b.Container.bsc.auth)
+	if err != nil {
+		return err
+	}
+	defer readAndCloseBody(resp.body)
+
+	if err := checkRespCode(resp.statusCode, []int{http.StatusOK}); err != nil {
+		return err
+	}
+
+	b.writeMetadata(resp.headers)
+	return nil
+}
+
+func (b *Blob) writeMetadata(h http.Header) {
+	metadata := make(map[string]string)
+	for k, v := range h {
+		// Can't trust CanonicalHeaderKey() to munge case
+		// reliably. "_" is allowed in identifiers:
+		// https://msdn.microsoft.com/en-us/library/azure/dd179414.aspx
+		// https://msdn.microsoft.com/library/aa664670(VS.71).aspx
+		// http://tools.ietf.org/html/rfc7230#section-3.2
+		// ...but "_" is considered invalid by
+		// CanonicalMIMEHeaderKey in
+		// https://golang.org/src/net/textproto/reader.go?s=14615:14659#L542
+		// so k can be "X-Ms-Meta-Lol" or "x-ms-meta-lol_rofl".
+		k = strings.ToLower(k)
+		if len(v) == 0 || !strings.HasPrefix(k, strings.ToLower(userDefinedMetadataHeaderPrefix)) {
+			continue
+		}
+		// metadata["lol"] = content of the last X-Ms-Meta-Lol header
+		k = k[len(userDefinedMetadataHeaderPrefix):]
+		metadata[k] = v[len(v)-1]
+	}
+
+	b.Metadata = BlobMetadata(metadata)
+}
+
+// DeleteBlobOptions includes the options for a delete blob operation
+type DeleteBlobOptions struct {
+	Timeout           uint
+	Snapshot          *time.Time
+	LeaseID           string `header:"x-ms-lease-id"`
+	DeleteSnapshots   *bool
+	IfModifiedSince   *time.Time `header:"If-Modified-Since"`
+	IfUnmodifiedSince *time.Time `header:"If-Unmodified-Since"`
+	IfMatch           string     `header:"If-Match"`
+	IfNoneMatch       string     `header:"If-None-Match"`
+	RequestID         string     `header:"x-ms-client-request-id"`
+}
+
+// Delete deletes the given blob from the specified container.
+// If the blob does not exists at the time of the Delete Blob operation, it
+// returns error.
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Delete-Blob
+func (b *Blob) Delete(options *DeleteBlobOptions) error {
+	resp, err := b.delete(options)
+	if err != nil {
+		return err
+	}
+	readAndCloseBody(resp.body)
+	return checkRespCode(resp.statusCode, []int{http.StatusAccepted})
+}
+
+// DeleteIfExists deletes the given blob from the specified container If the
+// blob is deleted with this call, returns true. Otherwise returns false.
+//
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Delete-Blob
+func (b *Blob) DeleteIfExists(options *DeleteBlobOptions) (bool, error) {
+	resp, err := b.delete(options)
+	if resp != nil {
+		defer readAndCloseBody(resp.body)
+		if resp.statusCode == http.StatusAccepted || resp.statusCode == http.StatusNotFound {
+			return resp.statusCode == http.StatusAccepted, nil
+		}
+	}
+	return false, err
+}
+
+func (b *Blob) delete(options *DeleteBlobOptions) (*storageResponse, error) {
+	params := url.Values{}
+	headers := b.Container.bsc.client.getStandardHeaders()
+
+	if options != nil {
+		params = addTimeout(params, options.Timeout)
+		params = addSnapshot(params, options.Snapshot)
+		headers = mergeHeaders(headers, headersFromStruct(*options))
+		if options.DeleteSnapshots != nil {
+			if *options.DeleteSnapshots {
+				headers["x-ms-delete-snapshots"] = "include"
+			} else {
+				headers["x-ms-delete-snapshots"] = "only"
+			}
+		}
+	}
+	uri := b.Container.bsc.client.getEndpoint(blobServiceName, b.buildPath(), params)
+	return b.Container.bsc.client.exec(http.MethodDelete, uri, headers, nil, b.Container.bsc.auth)
+}
+
+// helper method to construct the path to either a blob or container
+func pathForResource(container, name string) string {
+	if name != "" {
+		return fmt.Sprintf("/%s/%s", container, name)
+	}
+	return fmt.Sprintf("/%s", container)
+}