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storage.go
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storage.go
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// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package storage
import (
"bytes"
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/base64"
"encoding/pem"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"reflect"
"strconv"
"strings"
"time"
"unicode/utf8"
"google.golang.org/api/option"
"google.golang.org/api/transport"
"cloud.google.com/go/internal/optional"
"cloud.google.com/go/internal/version"
"golang.org/x/net/context"
"google.golang.org/api/googleapi"
raw "google.golang.org/api/storage/v1"
)
var (
ErrBucketNotExist = errors.New("storage: bucket doesn't exist")
ErrObjectNotExist = errors.New("storage: object doesn't exist")
)
const userAgent = "gcloud-golang-storage/20151204"
const (
// ScopeFullControl grants permissions to manage your
// data and permissions in Google Cloud Storage.
ScopeFullControl = raw.DevstorageFullControlScope
// ScopeReadOnly grants permissions to
// view your data in Google Cloud Storage.
ScopeReadOnly = raw.DevstorageReadOnlyScope
// ScopeReadWrite grants permissions to manage your
// data in Google Cloud Storage.
ScopeReadWrite = raw.DevstorageReadWriteScope
)
var xGoogHeader = fmt.Sprintf("gl-go/%s gccl/%s", version.Go(), version.Repo)
func setClientHeader(headers http.Header) {
headers.Set("x-goog-api-client", xGoogHeader)
}
// Client is a client for interacting with Google Cloud Storage.
//
// Clients should be reused instead of created as needed.
// The methods of Client are safe for concurrent use by multiple goroutines.
type Client struct {
hc *http.Client
raw *raw.Service
}
// NewClient creates a new Google Cloud Storage client.
// The default scope is ScopeFullControl. To use a different scope, like ScopeReadOnly, use option.WithScopes.
func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error) {
o := []option.ClientOption{
option.WithScopes(ScopeFullControl),
option.WithUserAgent(userAgent),
}
opts = append(o, opts...)
hc, ep, err := transport.NewHTTPClient(ctx, opts...)
if err != nil {
return nil, fmt.Errorf("dialing: %v", err)
}
rawService, err := raw.New(hc)
if err != nil {
return nil, fmt.Errorf("storage client: %v", err)
}
if ep != "" {
rawService.BasePath = ep
}
return &Client{
hc: hc,
raw: rawService,
}, nil
}
// Close closes the Client.
//
// Close need not be called at program exit.
func (c *Client) Close() error {
c.hc = nil
return nil
}
// SignedURLOptions allows you to restrict the access to the signed URL.
type SignedURLOptions struct {
// GoogleAccessID represents the authorizer of the signed URL generation.
// It is typically the Google service account client email address from
// the Google Developers Console in the form of "xxx@developer.gserviceaccount.com".
// Required.
GoogleAccessID string
// PrivateKey is the Google service account private key. It is obtainable
// from the Google Developers Console.
// At https://console.developers.google.com/project/<your-project-id>/apiui/credential,
// create a service account client ID or reuse one of your existing service account
// credentials. Click on the "Generate new P12 key" to generate and download
// a new private key. Once you download the P12 file, use the following command
// to convert it into a PEM file.
//
// $ openssl pkcs12 -in key.p12 -passin pass:notasecret -out key.pem -nodes
//
// Provide the contents of the PEM file as a byte slice.
// Exactly one of PrivateKey or SignBytes must be non-nil.
PrivateKey []byte
// SignBytes is a function for implementing custom signing.
// If your application is running on Google App Engine, you can use appengine's internal signing function:
// ctx := appengine.NewContext(request)
// acc, _ := appengine.ServiceAccount(ctx)
// url, err := SignedURL("bucket", "object", &SignedURLOptions{
// GoogleAccessID: acc,
// SignBytes: func(b []byte) ([]byte, error) {
// _, signedBytes, err := appengine.SignBytes(ctx, b)
// return signedBytes, err
// },
// // etc.
// })
//
// Exactly one of PrivateKey or SignBytes must be non-nil.
SignBytes func([]byte) ([]byte, error)
// Method is the HTTP method to be used with the signed URL.
// Signed URLs can be used with GET, HEAD, PUT, and DELETE requests.
// Required.
Method string
// Expires is the expiration time on the signed URL. It must be
// a datetime in the future.
// Required.
Expires time.Time
// ContentType is the content type header the client must provide
// to use the generated signed URL.
// Optional.
ContentType string
// Headers is a list of extention headers the client must provide
// in order to use the generated signed URL.
// Optional.
Headers []string
// MD5 is the base64 encoded MD5 checksum of the file.
// If provided, the client should provide the exact value on the request
// header in order to use the signed URL.
// Optional.
MD5 string
}
// SignedURL returns a URL for the specified object. Signed URLs allow
// the users access to a restricted resource for a limited time without having a
// Google account or signing in. For more information about the signed
// URLs, see https://cloud.google.com/storage/docs/accesscontrol#Signed-URLs.
func SignedURL(bucket, name string, opts *SignedURLOptions) (string, error) {
if opts == nil {
return "", errors.New("storage: missing required SignedURLOptions")
}
if opts.GoogleAccessID == "" {
return "", errors.New("storage: missing required GoogleAccessID")
}
if (opts.PrivateKey == nil) == (opts.SignBytes == nil) {
return "", errors.New("storage: exactly one of PrivateKey or SignedBytes must be set")
}
if opts.Method == "" {
return "", errors.New("storage: missing required method option")
}
if opts.Expires.IsZero() {
return "", errors.New("storage: missing required expires option")
}
if opts.MD5 != "" {
md5, err := base64.StdEncoding.DecodeString(opts.MD5)
if err != nil || len(md5) != 16 {
return "", errors.New("storage: invalid MD5 checksum")
}
}
signBytes := opts.SignBytes
if opts.PrivateKey != nil {
key, err := parseKey(opts.PrivateKey)
if err != nil {
return "", err
}
signBytes = func(b []byte) ([]byte, error) {
sum := sha256.Sum256(b)
return rsa.SignPKCS1v15(
rand.Reader,
key,
crypto.SHA256,
sum[:],
)
}
}
u := &url.URL{
Path: fmt.Sprintf("/%s/%s", bucket, name),
}
buf := &bytes.Buffer{}
fmt.Fprintf(buf, "%s\n", opts.Method)
fmt.Fprintf(buf, "%s\n", opts.MD5)
fmt.Fprintf(buf, "%s\n", opts.ContentType)
fmt.Fprintf(buf, "%d\n", opts.Expires.Unix())
if len(opts.Headers) > 0 {
fmt.Fprintf(buf, "%s\n", strings.Join(opts.Headers, "\n"))
}
fmt.Fprintf(buf, "%s", u.String())
b, err := signBytes(buf.Bytes())
if err != nil {
return "", err
}
encoded := base64.StdEncoding.EncodeToString(b)
u.Scheme = "https"
u.Host = "storage.googleapis.com"
q := u.Query()
q.Set("GoogleAccessId", opts.GoogleAccessID)
q.Set("Expires", fmt.Sprintf("%d", opts.Expires.Unix()))
q.Set("Signature", string(encoded))
u.RawQuery = q.Encode()
return u.String(), nil
}
// ObjectHandle provides operations on an object in a Google Cloud Storage bucket.
// Use BucketHandle.Object to get a handle.
type ObjectHandle struct {
c *Client
bucket string
object string
acl ACLHandle
gen int64 // a negative value indicates latest
conds *Conditions
encryptionKey []byte // AES-256 key
}
// ACL provides access to the object's access control list.
// This controls who can read and write this object.
// This call does not perform any network operations.
func (o *ObjectHandle) ACL() *ACLHandle {
return &o.acl
}
// Generation returns a new ObjectHandle that operates on a specific generation
// of the object.
// By default, the handle operates on the latest generation. Not
// all operations work when given a specific generation; check the API
// endpoints at https://cloud.google.com/storage/docs/json_api/ for details.
func (o *ObjectHandle) Generation(gen int64) *ObjectHandle {
o2 := *o
o2.gen = gen
return &o2
}
// If returns a new ObjectHandle that applies a set of preconditions.
// Preconditions already set on the ObjectHandle are ignored.
// Operations on the new handle will only occur if the preconditions are
// satisfied. See https://cloud.google.com/storage/docs/generations-preconditions
// for more details.
func (o *ObjectHandle) If(conds Conditions) *ObjectHandle {
o2 := *o
o2.conds = &conds
return &o2
}
// Key returns a new ObjectHandle that uses the supplied encryption
// key to encrypt and decrypt the object's contents.
//
// Encryption key must be a 32-byte AES-256 key.
// See https://cloud.google.com/storage/docs/encryption for details.
func (o *ObjectHandle) Key(encryptionKey []byte) *ObjectHandle {
o2 := *o
o2.encryptionKey = encryptionKey
return &o2
}
// Attrs returns meta information about the object.
// ErrObjectNotExist will be returned if the object is not found.
func (o *ObjectHandle) Attrs(ctx context.Context) (*ObjectAttrs, error) {
if err := o.validate(); err != nil {
return nil, err
}
call := o.c.raw.Objects.Get(o.bucket, o.object).Projection("full").Context(ctx)
if err := applyConds("Attrs", o.gen, o.conds, call); err != nil {
return nil, err
}
if err := setEncryptionHeaders(call.Header(), o.encryptionKey, false); err != nil {
return nil, err
}
var obj *raw.Object
var err error
setClientHeader(call.Header())
err = runWithRetry(ctx, func() error { obj, err = call.Do(); return err })
if e, ok := err.(*googleapi.Error); ok && e.Code == http.StatusNotFound {
return nil, ErrObjectNotExist
}
if err != nil {
return nil, err
}
return newObject(obj), nil
}
// Update updates an object with the provided attributes.
// All zero-value attributes are ignored.
// ErrObjectNotExist will be returned if the object is not found.
func (o *ObjectHandle) Update(ctx context.Context, uattrs ObjectAttrsToUpdate) (*ObjectAttrs, error) {
if err := o.validate(); err != nil {
return nil, err
}
var attrs ObjectAttrs
// Lists of fields to send, and set to null, in the JSON.
var forceSendFields, nullFields []string
if uattrs.ContentType != nil {
attrs.ContentType = optional.ToString(uattrs.ContentType)
forceSendFields = append(forceSendFields, "ContentType")
}
if uattrs.ContentLanguage != nil {
attrs.ContentLanguage = optional.ToString(uattrs.ContentLanguage)
// For ContentLanguage It's an error to send the empty string.
// Instead we send a null.
if attrs.ContentLanguage == "" {
nullFields = append(nullFields, "ContentLanguage")
} else {
forceSendFields = append(forceSendFields, "ContentLanguage")
}
}
if uattrs.ContentEncoding != nil {
attrs.ContentEncoding = optional.ToString(uattrs.ContentEncoding)
forceSendFields = append(forceSendFields, "ContentType")
}
if uattrs.ContentDisposition != nil {
attrs.ContentDisposition = optional.ToString(uattrs.ContentDisposition)
forceSendFields = append(forceSendFields, "ContentDisposition")
}
if uattrs.CacheControl != nil {
attrs.CacheControl = optional.ToString(uattrs.CacheControl)
forceSendFields = append(forceSendFields, "CacheControl")
}
if uattrs.Metadata != nil {
attrs.Metadata = uattrs.Metadata
if len(attrs.Metadata) == 0 {
// Sending the empty map is a no-op. We send null instead.
nullFields = append(nullFields, "Metadata")
} else {
forceSendFields = append(forceSendFields, "Metadata")
}
}
if uattrs.ACL != nil {
attrs.ACL = uattrs.ACL
// It's an error to attempt to delete the ACL, so
// we don't append to nullFields here.
forceSendFields = append(forceSendFields, "Acl")
}
rawObj := attrs.toRawObject(o.bucket)
rawObj.ForceSendFields = forceSendFields
rawObj.NullFields = nullFields
call := o.c.raw.Objects.Patch(o.bucket, o.object, rawObj).Projection("full").Context(ctx)
if err := applyConds("Update", o.gen, o.conds, call); err != nil {
return nil, err
}
if err := setEncryptionHeaders(call.Header(), o.encryptionKey, false); err != nil {
return nil, err
}
var obj *raw.Object
var err error
setClientHeader(call.Header())
err = runWithRetry(ctx, func() error { obj, err = call.Do(); return err })
if e, ok := err.(*googleapi.Error); ok && e.Code == http.StatusNotFound {
return nil, ErrObjectNotExist
}
if err != nil {
return nil, err
}
return newObject(obj), nil
}
// ObjectAttrsToUpdate is used to update the attributes of an object.
// Only fields set to non-nil values will be updated.
// Set a field to its zero value to delete it.
//
// For example, to change ContentType and delete ContentEncoding and
// Metadata, use
// ObjectAttrsToUpdate{
// ContentType: "text/html",
// ContentEncoding: "",
// Metadata: map[string]string{},
// }
type ObjectAttrsToUpdate struct {
ContentType optional.String
ContentLanguage optional.String
ContentEncoding optional.String
ContentDisposition optional.String
CacheControl optional.String
Metadata map[string]string // set to map[string]string{} to delete
ACL []ACLRule
}
// Delete deletes the single specified object.
func (o *ObjectHandle) Delete(ctx context.Context) error {
if err := o.validate(); err != nil {
return err
}
call := o.c.raw.Objects.Delete(o.bucket, o.object).Context(ctx)
if err := applyConds("Delete", o.gen, o.conds, call); err != nil {
return err
}
setClientHeader(call.Header())
err := runWithRetry(ctx, func() error { return call.Do() })
switch e := err.(type) {
case nil:
return nil
case *googleapi.Error:
if e.Code == http.StatusNotFound {
return ErrObjectNotExist
}
}
return err
}
// NewReader creates a new Reader to read the contents of the
// object.
// ErrObjectNotExist will be returned if the object is not found.
//
// The caller must call Close on the returned Reader when done reading.
func (o *ObjectHandle) NewReader(ctx context.Context) (*Reader, error) {
return o.NewRangeReader(ctx, 0, -1)
}
// NewRangeReader reads part of an object, reading at most length bytes
// starting at the given offset. If length is negative, the object is read
// until the end.
func (o *ObjectHandle) NewRangeReader(ctx context.Context, offset, length int64) (*Reader, error) {
if err := o.validate(); err != nil {
return nil, err
}
if offset < 0 {
return nil, fmt.Errorf("storage: invalid offset %d < 0", offset)
}
if o.conds != nil {
if err := o.conds.validate("NewRangeReader"); err != nil {
return nil, err
}
}
u := &url.URL{
Scheme: "https",
Host: "storage.googleapis.com",
Path: fmt.Sprintf("/%s/%s", o.bucket, o.object),
RawQuery: conditionsQuery(o.gen, o.conds),
}
verb := "GET"
if length == 0 {
verb = "HEAD"
}
req, err := http.NewRequest(verb, u.String(), nil)
if err != nil {
return nil, err
}
req = withContext(req, ctx)
if length < 0 && offset > 0 {
req.Header.Set("Range", fmt.Sprintf("bytes=%d-", offset))
} else if length > 0 {
req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", offset, offset+length-1))
}
if err := setEncryptionHeaders(req.Header, o.encryptionKey, false); err != nil {
return nil, err
}
var res *http.Response
err = runWithRetry(ctx, func() error {
res, err = o.c.hc.Do(req)
if err != nil {
return err
}
if res.StatusCode == http.StatusNotFound {
res.Body.Close()
return ErrObjectNotExist
}
if res.StatusCode < 200 || res.StatusCode > 299 {
body, _ := ioutil.ReadAll(res.Body)
res.Body.Close()
return &googleapi.Error{
Code: res.StatusCode,
Header: res.Header,
Body: string(body),
}
}
if offset > 0 && length != 0 && res.StatusCode != http.StatusPartialContent {
res.Body.Close()
return errors.New("storage: partial request not satisfied")
}
return nil
})
if err != nil {
return nil, err
}
var size int64 // total size of object, even if a range was requested.
if res.StatusCode == http.StatusPartialContent {
cr := strings.TrimSpace(res.Header.Get("Content-Range"))
if !strings.HasPrefix(cr, "bytes ") || !strings.Contains(cr, "/") {
return nil, fmt.Errorf("storage: invalid Content-Range %q", cr)
}
size, err = strconv.ParseInt(cr[strings.LastIndex(cr, "/")+1:], 10, 64)
if err != nil {
return nil, fmt.Errorf("storage: invalid Content-Range %q", cr)
}
} else {
size = res.ContentLength
}
remain := res.ContentLength
body := res.Body
if length == 0 {
remain = 0
body.Close()
body = emptyBody
}
var (
checkCRC bool
crc uint32
)
// Even if there is a CRC header, we can't compute the hash on partial data.
if remain == size {
crc, checkCRC = parseCRC32c(res)
}
return &Reader{
body: body,
size: size,
remain: remain,
contentType: res.Header.Get("Content-Type"),
wantCRC: crc,
checkCRC: checkCRC,
}, nil
}
func parseCRC32c(res *http.Response) (uint32, bool) {
const prefix = "crc32c="
for _, spec := range res.Header["X-Goog-Hash"] {
if strings.HasPrefix(spec, prefix) {
c, err := decodeUint32(spec[len(prefix):])
if err == nil {
return c, true
}
}
}
return 0, false
}
var emptyBody = ioutil.NopCloser(strings.NewReader(""))
// NewWriter returns a storage Writer that writes to the GCS object
// associated with this ObjectHandle.
//
// A new object will be created unless an object with this name already exists.
// Otherwise any previous object with the same name will be replaced.
// The object will not be available (and any previous object will remain)
// until Close has been called.
//
// Attributes can be set on the object by modifying the returned Writer's
// ObjectAttrs field before the first call to Write. If no ContentType
// attribute is specified, the content type will be automatically sniffed
// using net/http.DetectContentType.
//
// It is the caller's responsibility to call Close when writing is done.
func (o *ObjectHandle) NewWriter(ctx context.Context) *Writer {
return &Writer{
ctx: ctx,
o: o,
donec: make(chan struct{}),
ObjectAttrs: ObjectAttrs{Name: o.object},
ChunkSize: googleapi.DefaultUploadChunkSize,
}
}
func (o *ObjectHandle) validate() error {
if o.bucket == "" {
return errors.New("storage: bucket name is empty")
}
if o.object == "" {
return errors.New("storage: object name is empty")
}
if !utf8.ValidString(o.object) {
return fmt.Errorf("storage: object name %q is not valid UTF-8", o.object)
}
return nil
}
// parseKey converts the binary contents of a private key file
// to an *rsa.PrivateKey. It detects whether the private key is in a
// PEM container or not. If so, it extracts the the private key
// from PEM container before conversion. It only supports PEM
// containers with no passphrase.
func parseKey(key []byte) (*rsa.PrivateKey, error) {
if block, _ := pem.Decode(key); block != nil {
key = block.Bytes
}
parsedKey, err := x509.ParsePKCS8PrivateKey(key)
if err != nil {
parsedKey, err = x509.ParsePKCS1PrivateKey(key)
if err != nil {
return nil, err
}
}
parsed, ok := parsedKey.(*rsa.PrivateKey)
if !ok {
return nil, errors.New("oauth2: private key is invalid")
}
return parsed, nil
}
func toRawObjectACL(oldACL []ACLRule) []*raw.ObjectAccessControl {
var acl []*raw.ObjectAccessControl
if len(oldACL) > 0 {
acl = make([]*raw.ObjectAccessControl, len(oldACL))
for i, rule := range oldACL {
acl[i] = &raw.ObjectAccessControl{
Entity: string(rule.Entity),
Role: string(rule.Role),
}
}
}
return acl
}
// toRawObject copies the editable attributes from o to the raw library's Object type.
func (o *ObjectAttrs) toRawObject(bucket string) *raw.Object {
acl := toRawObjectACL(o.ACL)
return &raw.Object{
Bucket: bucket,
Name: o.Name,
ContentType: o.ContentType,
ContentEncoding: o.ContentEncoding,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
ContentDisposition: o.ContentDisposition,
StorageClass: o.StorageClass,
Acl: acl,
Metadata: o.Metadata,
}
}
// ObjectAttrs represents the metadata for a Google Cloud Storage (GCS) object.
type ObjectAttrs struct {
// Bucket is the name of the bucket containing this GCS object.
// This field is read-only.
Bucket string
// Name is the name of the object within the bucket.
// This field is read-only.
Name string
// ContentType is the MIME type of the object's content.
ContentType string
// ContentLanguage is the content language of the object's content.
ContentLanguage string
// CacheControl is the Cache-Control header to be sent in the response
// headers when serving the object data.
CacheControl string
// ACL is the list of access control rules for the object.
ACL []ACLRule
// Owner is the owner of the object. This field is read-only.
//
// If non-zero, it is in the form of "user-<userId>".
Owner string
// Size is the length of the object's content. This field is read-only.
Size int64
// ContentEncoding is the encoding of the object's content.
ContentEncoding string
// ContentDisposition is the optional Content-Disposition header of the object
// sent in the response headers.
ContentDisposition string
// MD5 is the MD5 hash of the object's content. This field is read-only.
MD5 []byte
// CRC32C is the CRC32 checksum of the object's content using
// the Castagnoli93 polynomial. This field is read-only.
CRC32C uint32
// MediaLink is an URL to the object's content. This field is read-only.
MediaLink string
// Metadata represents user-provided metadata, in key/value pairs.
// It can be nil if no metadata is provided.
Metadata map[string]string
// Generation is the generation number of the object's content.
// This field is read-only.
Generation int64
// Metageneration is the version of the metadata for this
// object at this generation. This field is used for preconditions
// and for detecting changes in metadata. A metageneration number
// is only meaningful in the context of a particular generation
// of a particular object. This field is read-only.
Metageneration int64
// StorageClass is the storage class of the object.
// This value defines how objects in the bucket are stored and
// determines the SLA and the cost of storage. Typical values are
// "MULTI_REGIONAL", "REGIONAL", "NEARLINE", "COLDLINE", "STANDARD"
// and "DURABLE_REDUCED_AVAILABILITY".
// It defaults to "STANDARD", which is equivalent to "MULTI_REGIONAL"
// or "REGIONAL" depending on the bucket's location settings.
StorageClass string
// Created is the time the object was created. This field is read-only.
Created time.Time
// Deleted is the time the object was deleted.
// If not deleted, it is the zero value. This field is read-only.
Deleted time.Time
// Updated is the creation or modification time of the object.
// For buckets with versioning enabled, changing an object's
// metadata does not change this property. This field is read-only.
Updated time.Time
// CustomerKeySHA256 is the base64-encoded SHA-256 hash of the
// customer-supplied encryption key for the object. It is empty if there is
// no customer-supplied encryption key.
// See // https://cloud.google.com/storage/docs/encryption for more about
// encryption in Google Cloud Storage.
CustomerKeySHA256 string
// Prefix is set only for ObjectAttrs which represent synthetic "directory
// entries" when iterating over buckets using Query.Delimiter. See
// ObjectIterator.Next. When set, no other fields in ObjectAttrs will be
// populated.
Prefix string
}
// convertTime converts a time in RFC3339 format to time.Time.
// If any error occurs in parsing, the zero-value time.Time is silently returned.
func convertTime(t string) time.Time {
var r time.Time
if t != "" {
r, _ = time.Parse(time.RFC3339, t)
}
return r
}
func newObject(o *raw.Object) *ObjectAttrs {
if o == nil {
return nil
}
acl := make([]ACLRule, len(o.Acl))
for i, rule := range o.Acl {
acl[i] = ACLRule{
Entity: ACLEntity(rule.Entity),
Role: ACLRole(rule.Role),
}
}
owner := ""
if o.Owner != nil {
owner = o.Owner.Entity
}
md5, _ := base64.StdEncoding.DecodeString(o.Md5Hash)
crc32c, _ := decodeUint32(o.Crc32c)
var sha256 string
if o.CustomerEncryption != nil {
sha256 = o.CustomerEncryption.KeySha256
}
return &ObjectAttrs{
Bucket: o.Bucket,
Name: o.Name,
ContentType: o.ContentType,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
ACL: acl,
Owner: owner,
ContentEncoding: o.ContentEncoding,
Size: int64(o.Size),
MD5: md5,
CRC32C: crc32c,
MediaLink: o.MediaLink,
Metadata: o.Metadata,
Generation: o.Generation,
Metageneration: o.Metageneration,
StorageClass: o.StorageClass,
CustomerKeySHA256: sha256,
Created: convertTime(o.TimeCreated),
Deleted: convertTime(o.TimeDeleted),
Updated: convertTime(o.Updated),
}
}
// Decode a uint32 encoded in Base64 in big-endian byte order.
func decodeUint32(b64 string) (uint32, error) {
d, err := base64.StdEncoding.DecodeString(b64)
if err != nil {
return 0, err
}
if len(d) != 4 {
return 0, fmt.Errorf("storage: %q does not encode a 32-bit value", d)
}
return uint32(d[0])<<24 + uint32(d[1])<<16 + uint32(d[2])<<8 + uint32(d[3]), nil
}
// Encode a uint32 as Base64 in big-endian byte order.
func encodeUint32(u uint32) string {
b := []byte{byte(u >> 24), byte(u >> 16), byte(u >> 8), byte(u)}
return base64.StdEncoding.EncodeToString(b)
}
// Query represents a query to filter objects from a bucket.
type Query struct {
// Delimiter returns results in a directory-like fashion.
// Results will contain only objects whose names, aside from the
// prefix, do not contain delimiter. Objects whose names,
// aside from the prefix, contain delimiter will have their name,
// truncated after the delimiter, returned in prefixes.
// Duplicate prefixes are omitted.
// Optional.
Delimiter string
// Prefix is the prefix filter to query objects
// whose names begin with this prefix.
// Optional.
Prefix string
// Versions indicates whether multiple versions of the same
// object will be included in the results.
Versions bool
}
// contentTyper implements ContentTyper to enable an
// io.ReadCloser to specify its MIME type.
type contentTyper struct {
io.Reader
t string
}
func (c *contentTyper) ContentType() string {
return c.t
}
// Conditions constrain methods to act on specific generations of
// objects.
//
// The zero value is an empty set of constraints. Not all conditions or
// combinations of conditions are applicable to all methods.
// See https://cloud.google.com/storage/docs/generations-preconditions
// for details on how these operate.
type Conditions struct {
// Generation constraints.
// At most one of the following can be set to a non-zero value.
// GenerationMatch specifies that the object must have the given generation
// for the operation to occur.
// If GenerationMatch is zero, it has no effect.
// Use DoesNotExist to specify that the object does not exist in the bucket.
GenerationMatch int64
// GenerationNotMatch specifies that the object must not have the given
// generation for the operation to occur.
// If GenerationNotMatch is zero, it has no effect.
GenerationNotMatch int64
// DoesNotExist specifies that the object must not exist in the bucket for
// the operation to occur.
// If DoesNotExist is false, it has no effect.
DoesNotExist bool
// Metadata generation constraints.
// At most one of the following can be set to a non-zero value.
// MetagenerationMatch specifies that the object must have the given
// metageneration for the operation to occur.
// If MetagenerationMatch is zero, it has no effect.
MetagenerationMatch int64
// MetagenerationNotMatch specifies that the object must not have the given
// metageneration for the operation to occur.
// If MetagenerationNotMatch is zero, it has no effect.
MetagenerationNotMatch int64
}
func (c *Conditions) validate(method string) error {
if *c == (Conditions{}) {
return fmt.Errorf("storage: %s: empty conditions", method)
}
if !c.isGenerationValid() {
return fmt.Errorf("storage: %s: multiple conditions specified for generation", method)
}
if !c.isMetagenerationValid() {
return fmt.Errorf("storage: %s: multiple conditions specified for metageneration", method)
}
return nil
}
func (c *Conditions) isGenerationValid() bool {
n := 0
if c.GenerationMatch != 0 {
n++
}
if c.GenerationNotMatch != 0 {
n++
}
if c.DoesNotExist {
n++
}
return n <= 1
}
func (c *Conditions) isMetagenerationValid() bool {
return c.MetagenerationMatch == 0 || c.MetagenerationNotMatch == 0
}
// applyConds modifies the provided call using the conditions in conds.
// call is something that quacks like a *raw.WhateverCall.
func applyConds(method string, gen int64, conds *Conditions, call interface{}) error {
cval := reflect.ValueOf(call)
if gen >= 0 {
if !setConditionField(cval, "Generation", gen) {
return fmt.Errorf("storage: %s: generation not supported", method)
}
}
if conds == nil {
return nil
}
if err := conds.validate(method); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
if !setConditionField(cval, "IfGenerationMatch", conds.GenerationMatch) {
return fmt.Errorf("storage: %s: ifGenerationMatch not supported", method)
}
case conds.GenerationNotMatch != 0:
if !setConditionField(cval, "IfGenerationNotMatch", conds.GenerationNotMatch) {
return fmt.Errorf("storage: %s: ifGenerationNotMatch not supported", method)
}
case conds.DoesNotExist:
if !setConditionField(cval, "IfGenerationMatch", int64(0)) {
return fmt.Errorf("storage: %s: DoesNotExist not supported", method)
}
}
switch {
case conds.MetagenerationMatch != 0:
if !setConditionField(cval, "IfMetagenerationMatch", conds.MetagenerationMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationMatch not supported", method)
}
case conds.MetagenerationNotMatch != 0:
if !setConditionField(cval, "IfMetagenerationNotMatch", conds.MetagenerationNotMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationNotMatch not supported", method)
}
}
return nil
}
func applySourceConds(gen int64, conds *Conditions, call *raw.ObjectsRewriteCall) error {
if gen >= 0 {
call.SourceGeneration(gen)
}
if conds == nil {
return nil
}
if err := conds.validate("CopyTo source"); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
call.IfSourceGenerationMatch(conds.GenerationMatch)