rclone/webdav/webdav.go
Nick Craig-Wood e612673ea0 webdav: fix Copy, Move and DirMove to be more compatible
The fix was to use an absolute URL in the Destination: as per RFC2518

This makes it compatible with the golang.org/x/net/webdav server
2017-10-25 22:59:22 +01:00

929 lines
24 KiB
Go

// Package webdav provides an interface to the Webdav
// object storage system.
package webdav
// Owncloud: Getting Oc-Checksum:
// SHA1:f572d396fae9206628714fb2ce00f72e94f2258f on HEAD but not on
// nextcloud?
// docs for file webdav
// https://docs.nextcloud.com/server/12/developer_manual/client_apis/WebDAV/index.html
// indicates checksums can be set as metadata here
// https://github.com/nextcloud/server/issues/6129
// owncloud seems to have checksums as metadata though - can read them
// SetModTime might be possible
// https://stackoverflow.com/questions/3579608/webdav-can-a-client-modify-the-mtime-of-a-file
// ...support for a PROPSET to lastmodified (mind the missing get) which does the utime() call might be an option.
// For example the ownCloud WebDAV server does it that way.
import (
"fmt"
"io"
"net/http"
"net/url"
"path"
"regexp"
"strings"
"time"
"github.com/ncw/rclone/fs"
"github.com/ncw/rclone/pacer"
"github.com/ncw/rclone/rest"
"github.com/ncw/rclone/webdav/api"
"github.com/pkg/errors"
)
const (
minSleep = 10 * time.Millisecond
maxSleep = 2 * time.Second
decayConstant = 2 // bigger for slower decay, exponential
)
// Register with Fs
func init() {
fs.Register(&fs.RegInfo{
Name: "webdav",
Description: "Webdav",
NewFs: NewFs,
Options: []fs.Option{{
Name: "url",
Help: "URL of http host to connect to",
Optional: false,
Examples: []fs.OptionExample{{
Value: "https://example.com",
Help: "Connect to example.com",
}},
}, {
Name: "vendor",
Help: "Name of the Webdav site/service/software you are using",
Optional: false,
Examples: []fs.OptionExample{{
Value: "nextcloud",
Help: "Nextcloud",
}, {
Value: "owncloud",
Help: "Owncloud",
}, {
Value: "other",
Help: "Other site/service or software",
}},
}, {
Name: "user",
Help: "User name",
Optional: true,
}, {
Name: "pass",
Help: "Password.",
Optional: true,
IsPassword: true,
}},
})
}
// Fs represents a remote webdav
type Fs struct {
name string // name of this remote
root string // the path we are working on
features *fs.Features // optional features
endpoint *url.URL // URL of the host
endpointURL string // endpoint as a string
srv *rest.Client // the connection to the one drive server
pacer *pacer.Pacer // pacer for API calls
user string // username
pass string // password
vendor string // name of the vendor
precision time.Duration // mod time precision
canStream bool // set if can stream
useOCMtime bool // set if can use X-OC-Mtime
}
// Object describes a webdav object
//
// Will definitely have info but maybe not meta
type Object struct {
fs *Fs // what this object is part of
remote string // The remote path
hasMetaData bool // whether info below has been set
size int64 // size of the object
modTime time.Time // modification time of the object
id string // ID of the object
sha1 string // SHA-1 of the object content
}
// ------------------------------------------------------------
// Name of the remote (as passed into NewFs)
func (f *Fs) Name() string {
return f.name
}
// Root of the remote (as passed into NewFs)
func (f *Fs) Root() string {
return f.root
}
// String converts this Fs to a string
func (f *Fs) String() string {
return fmt.Sprintf("webdav root '%s'", f.root)
}
// Features returns the optional features of this Fs
func (f *Fs) Features() *fs.Features {
return f.features
}
// Pattern to match a webdav path
var matcher = regexp.MustCompile(`^([^/]*)(.*)$`)
// parsePath parses an webdav 'url'
func parsePath(path string) (root string) {
root = strings.Trim(path, "/")
return
}
// retryErrorCodes is a slice of error codes that we will retry
var retryErrorCodes = []int{
429, // Too Many Requests.
500, // Internal Server Error
502, // Bad Gateway
503, // Service Unavailable
504, // Gateway Timeout
509, // Bandwidth Limit Exceeded
}
// shouldRetry returns a boolean as to whether this resp and err
// deserve to be retried. It returns the err as a convenience
func shouldRetry(resp *http.Response, err error) (bool, error) {
return fs.ShouldRetry(err) || fs.ShouldRetryHTTP(resp, retryErrorCodes), err
}
// itemIsDir returns true if the item is a directory
//
// When a client sees a resourcetype it doesn't recognize it should
// assume it is a regular non-collection resource. [WebDav book by
// Lisa Dusseault ch 7.5.8 p170]
func itemIsDir(item *api.Response) bool {
if t := item.Props.Type; t != nil {
if t.Space == "DAV:" && t.Local == "collection" {
return true
}
fs.Debugf(nil, "Unknown resource type %q/%q on %q", t.Space, t.Local, item.Props.Name)
}
return false
}
// readMetaDataForPath reads the metadata from the path
func (f *Fs) readMetaDataForPath(path string) (info *api.Prop, err error) {
// FIXME how do we read back additional properties?
opts := rest.Opts{
Method: "PROPFIND",
Path: f.filePath(path),
}
var result api.Multistatus
var resp *http.Response
err = f.pacer.Call(func() (bool, error) {
resp, err = f.srv.CallXML(&opts, nil, &result)
return shouldRetry(resp, err)
})
if apiErr, ok := err.(*api.Error); ok {
// does not exist
if apiErr.StatusCode == http.StatusNotFound {
return nil, fs.ErrorObjectNotFound
}
}
if err != nil {
return nil, errors.Wrap(err, "read metadata failed")
}
if len(result.Responses) < 1 {
return nil, fs.ErrorObjectNotFound
}
item := result.Responses[0]
if !item.Props.StatusOK() {
return nil, fs.ErrorObjectNotFound
}
if itemIsDir(&item) {
return nil, fs.ErrorNotAFile
}
return &item.Props, nil
}
// errorHandler parses a non 2xx error response into an error
func errorHandler(resp *http.Response) error {
// Decode error response
errResponse := new(api.Error)
err := rest.DecodeXML(resp, &errResponse)
if err != nil {
fs.Debugf(nil, "Couldn't decode error response: %v", err)
}
errResponse.Status = resp.Status
errResponse.StatusCode = resp.StatusCode
return errResponse
}
// addShlash makes sure s is terminated with a / if non empty
func addSlash(s string) string {
if s != "" && !strings.HasSuffix(s, "/") {
s += "/"
}
return s
}
// filePath returns a file path (f.root, file)
func (f *Fs) filePath(file string) string {
return rest.URLEscape(path.Join(f.root, file))
}
// dirPath returns a directory path (f.root, dir)
func (f *Fs) dirPath(dir string) string {
return addSlash(f.filePath(dir))
}
// filePath returns a file path (f.root, remote)
func (o *Object) filePath() string {
return o.fs.filePath(o.remote)
}
// NewFs constructs an Fs from the path, container:path
func NewFs(name, root string) (fs.Fs, error) {
endpoint := fs.ConfigFileGet(name, "url")
if !strings.HasSuffix(endpoint, "/") {
endpoint += "/"
}
user := fs.ConfigFileGet(name, "user")
pass := fs.ConfigFileGet(name, "pass")
if pass != "" {
var err error
pass, err = fs.Reveal(pass)
if err != nil {
return nil, errors.Wrap(err, "couldn't decrypt password")
}
}
vendor := fs.ConfigFileGet(name, "vendor")
// Parse the endpoint
u, err := url.Parse(endpoint)
if err != nil {
return nil, err
}
f := &Fs{
name: name,
root: root,
endpoint: u,
endpointURL: u.String(),
srv: rest.NewClient(fs.Config.Client()).SetRoot(u.String()).SetUserPass(user, pass),
pacer: pacer.New().SetMinSleep(minSleep).SetMaxSleep(maxSleep).SetDecayConstant(decayConstant),
user: user,
pass: pass,
precision: fs.ModTimeNotSupported,
}
f.features = (&fs.Features{
CanHaveEmptyDirectories: true,
}).Fill(f)
f.srv.SetErrorHandler(errorHandler)
f.setQuirks(vendor)
if root != "" {
// Check to see if the root actually an existing file
remote := path.Base(root)
f.root = path.Dir(root)
if f.root == "." {
f.root = ""
}
_, err := f.NewObject(remote)
if err != nil {
if errors.Cause(err) == fs.ErrorObjectNotFound || errors.Cause(err) == fs.ErrorNotAFile {
// File doesn't exist so return old f
f.root = root
return f, nil
}
return nil, err
}
// return an error with an fs which points to the parent
return f, fs.ErrorIsFile
}
return f, nil
}
// setQuirks adjusts the Fs for the vendor passed in
func (f *Fs) setQuirks(vendor string) {
if vendor == "" {
vendor = "other"
}
f.vendor = vendor
switch vendor {
case "owncloud":
f.canStream = true
f.precision = time.Second
f.useOCMtime = true
case "nextcloud":
f.precision = time.Second
f.useOCMtime = true
case "other":
default:
fs.Debugf(f, "Unknown vendor %q", vendor)
}
// Remove PutStream from optional features
if !f.canStream {
f.features.PutStream = nil
}
}
// Return an Object from a path
//
// If it can't be found it returns the error fs.ErrorObjectNotFound.
func (f *Fs) newObjectWithInfo(remote string, info *api.Prop) (fs.Object, error) {
o := &Object{
fs: f,
remote: remote,
}
var err error
if info != nil {
// Set info
err = o.setMetaData(info)
} else {
err = o.readMetaData() // reads info and meta, returning an error
}
if err != nil {
return nil, err
}
return o, nil
}
// NewObject finds the Object at remote. If it can't be found
// it returns the error fs.ErrorObjectNotFound.
func (f *Fs) NewObject(remote string) (fs.Object, error) {
return f.newObjectWithInfo(remote, nil)
}
// list the objects into the function supplied
//
// If directories is set it only sends directories
// User function to process a File item from listAll
//
// Should return true to finish processing
type listAllFn func(string, bool, *api.Prop) bool
// Lists the directory required calling the user function on each item found
//
// If the user fn ever returns true then it early exits with found = true
func (f *Fs) listAll(dir string, directoriesOnly bool, filesOnly bool, fn listAllFn) (found bool, err error) {
opts := rest.Opts{
Method: "PROPFIND",
Path: f.dirPath(dir), // FIXME Should not start with /
ExtraHeaders: map[string]string{
"Depth": "1",
},
}
var result api.Multistatus
var resp *http.Response
err = f.pacer.Call(func() (bool, error) {
resp, err = f.srv.CallXML(&opts, nil, &result)
return shouldRetry(resp, err)
})
if err != nil {
if apiErr, ok := err.(*api.Error); ok {
// does not exist
if apiErr.StatusCode == http.StatusNotFound {
return found, fs.ErrorDirNotFound
}
}
return found, errors.Wrap(err, "couldn't list files")
}
//fmt.Printf("result = %#v", &result)
baseURL, err := rest.URLJoin(f.endpoint, opts.Path)
if err != nil {
return false, errors.Wrap(err, "couldn't join URL")
}
for i := range result.Responses {
item := &result.Responses[i]
isDir := itemIsDir(item)
// Find name
u, err := rest.URLJoin(baseURL, item.Href)
if err != nil {
fs.Errorf(nil, "URL Join failed for %q and %q: %v", baseURL, item.Href, err)
continue
}
// Make sure directories end with a /
if isDir {
u.Path = addSlash(u.Path)
}
if !strings.HasPrefix(u.Path, baseURL.Path) {
fs.Debugf(nil, "Item with unknown path received: %q, %q", u.Path, baseURL.Path)
continue
}
remote := path.Join(dir, u.Path[len(baseURL.Path):])
if strings.HasSuffix(remote, "/") {
remote = remote[:len(remote)-1]
}
// the listing contains info about itself which we ignore
if remote == dir {
continue
}
// Check OK
if !item.Props.StatusOK() {
fs.Debugf(remote, "Ignoring item with bad status %q", item.Props.Status)
continue
}
if isDir {
if filesOnly {
continue
}
} else {
if directoriesOnly {
continue
}
}
// item.Name = restoreReservedChars(item.Name)
if fn(remote, isDir, &item.Props) {
found = true
break
}
}
return
}
// List the objects and directories in dir into entries. The
// entries can be returned in any order but should be for a
// complete directory.
//
// dir should be "" to list the root, and should not have
// trailing slashes.
//
// This should return ErrDirNotFound if the directory isn't
// found.
func (f *Fs) List(dir string) (entries fs.DirEntries, err error) {
var iErr error
_, err = f.listAll(dir, false, false, func(remote string, isDir bool, info *api.Prop) bool {
if isDir {
d := fs.NewDir(remote, time.Time(info.Modified))
// .SetID(info.ID)
// FIXME more info from dir? can set size, items?
entries = append(entries, d)
} else {
o, err := f.newObjectWithInfo(remote, info)
if err != nil {
iErr = err
return true
}
entries = append(entries, o)
}
return false
})
if err != nil {
return nil, err
}
if iErr != nil {
return nil, iErr
}
return entries, nil
}
// Creates from the parameters passed in a half finished Object which
// must have setMetaData called on it
//
// Used to create new objects
func (f *Fs) createObject(remote string, modTime time.Time, size int64) (o *Object) {
// Temporary Object under construction
o = &Object{
fs: f,
remote: remote,
size: size,
modTime: modTime,
}
return o
}
// Put the object
//
// Copy the reader in to the new object which is returned
//
// The new object may have been created if an error is returned
func (f *Fs) Put(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
o := f.createObject(src.Remote(), src.ModTime(), src.Size())
return o, o.Update(in, src, options...)
}
// PutStream uploads to the remote path with the modTime given of indeterminate size
func (f *Fs) PutStream(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
return f.Put(in, src, options...)
}
// mkParentDir makes the parent of the native path dirPath if
// necessary and any directories above that
func (f *Fs) mkParentDir(dirPath string) error {
parent := path.Dir(dirPath)
if parent == "." {
parent = ""
}
return f.mkdir(parent)
}
// mkdir makes the directory and parents using native paths
func (f *Fs) mkdir(dirPath string) error {
// We assume the root is already ceated
if dirPath == "" {
return nil
}
opts := rest.Opts{
Method: "MKCOL",
Path: dirPath,
NoResponse: true,
}
err := f.pacer.Call(func() (bool, error) {
resp, err := f.srv.Call(&opts)
return shouldRetry(resp, err)
})
if apiErr, ok := err.(*api.Error); ok {
// already exists
if apiErr.StatusCode == http.StatusMethodNotAllowed {
return nil
}
// parent does not exists
if apiErr.StatusCode == http.StatusConflict {
err = f.mkParentDir(dirPath)
if err == nil {
err = f.mkdir(dirPath)
}
}
}
return err
}
// Mkdir creates the directory if it doesn't exist
func (f *Fs) Mkdir(dir string) error {
dirPath := f.dirPath(dir)
return f.mkdir(dirPath)
}
// dirNotEmpty returns true if the directory exists and is not Empty
//
// if the directory does not exist then err will be ErrorDirNotFound
func (f *Fs) dirNotEmpty(dir string) (found bool, err error) {
return f.listAll(dir, false, false, func(remote string, isDir bool, info *api.Prop) bool {
return true
})
}
// purgeCheck removes the root directory, if check is set then it
// refuses to do so if it has anything in
func (f *Fs) purgeCheck(dir string, check bool) error {
if check {
notEmpty, err := f.dirNotEmpty(dir)
if err != nil {
return err
}
if notEmpty {
return fs.ErrorDirectoryNotEmpty
}
}
opts := rest.Opts{
Method: "DELETE",
Path: f.dirPath(dir),
NoResponse: true,
}
var resp *http.Response
var err error
err = f.pacer.Call(func() (bool, error) {
resp, err = f.srv.CallXML(&opts, nil, nil)
return shouldRetry(resp, err)
})
if err != nil {
return errors.Wrap(err, "rmdir failed")
}
// FIXME parse Multistatus response
return nil
}
// Rmdir deletes the root folder
//
// Returns an error if it isn't empty
func (f *Fs) Rmdir(dir string) error {
return f.purgeCheck(dir, true)
}
// Precision return the precision of this Fs
func (f *Fs) Precision() time.Duration {
return f.precision
}
// Copy or Move src to this remote using server side copy operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantCopy/fs.ErrorCantMove
func (f *Fs) copyOrMove(src fs.Object, remote string, method string) (fs.Object, error) {
srcObj, ok := src.(*Object)
if !ok {
fs.Debugf(src, "Can't copy - not same remote type")
if method == "COPY" {
return nil, fs.ErrorCantCopy
}
return nil, fs.ErrorCantMove
}
dstPath := f.filePath(remote)
err := f.mkParentDir(dstPath)
if err != nil {
return nil, errors.Wrap(err, "Copy mkParentDir failed")
}
destinationURL, err := rest.URLJoin(f.endpoint, dstPath)
if err != nil {
return nil, errors.Wrap(err, "copyOrMove couldn't join URL")
}
var resp *http.Response
opts := rest.Opts{
Method: method,
Path: srcObj.filePath(),
NoResponse: true,
ExtraHeaders: map[string]string{
"Destination": destinationURL.String(),
"Overwrite": "F",
},
}
if f.useOCMtime {
opts.ExtraHeaders["X-OC-Mtime"] = fmt.Sprintf("%f", float64(src.ModTime().UnixNano())/1E9)
}
err = f.pacer.Call(func() (bool, error) {
resp, err = f.srv.Call(&opts)
return shouldRetry(resp, err)
})
if err != nil {
return nil, errors.Wrap(err, "Copy call failed")
}
dstObj, err := f.NewObject(remote)
if err != nil {
return nil, errors.Wrap(err, "Copy NewObject failed")
}
return dstObj, nil
}
// Copy src to this remote using server side copy operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantCopy
func (f *Fs) Copy(src fs.Object, remote string) (fs.Object, error) {
return f.copyOrMove(src, remote, "COPY")
}
// Purge deletes all the files and the container
//
// Optional interface: Only implement this if you have a way of
// deleting all the files quicker than just running Remove() on the
// result of List()
func (f *Fs) Purge() error {
return f.purgeCheck("", false)
}
// Move src to this remote using server side move operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantMove
func (f *Fs) Move(src fs.Object, remote string) (fs.Object, error) {
return f.copyOrMove(src, remote, "MOVE")
}
// DirMove moves src, srcRemote to this remote at dstRemote
// using server side move operations.
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantDirMove
//
// If destination exists then return fs.ErrorDirExists
func (f *Fs) DirMove(src fs.Fs, srcRemote, dstRemote string) error {
srcFs, ok := src.(*Fs)
if !ok {
fs.Debugf(srcFs, "Can't move directory - not same remote type")
return fs.ErrorCantDirMove
}
srcPath := srcFs.filePath(srcRemote)
dstPath := f.filePath(dstRemote)
// Check if destination exists
_, err := f.dirNotEmpty(dstRemote)
if err == nil {
return fs.ErrorDirExists
}
if err != fs.ErrorDirNotFound {
return errors.Wrap(err, "DirMove dirExists dst failed")
}
// Make sure the parent directory exists
err = f.mkParentDir(dstPath)
if err != nil {
return errors.Wrap(err, "DirMove mkParentDir dst failed")
}
destinationURL, err := rest.URLJoin(f.endpoint, dstPath)
if err != nil {
return errors.Wrap(err, "DirMove couldn't join URL")
}
var resp *http.Response
opts := rest.Opts{
Method: "MOVE",
Path: addSlash(srcPath),
NoResponse: true,
ExtraHeaders: map[string]string{
"Destination": addSlash(destinationURL.String()),
"Overwrite": "F",
},
}
err = f.pacer.Call(func() (bool, error) {
resp, err = f.srv.Call(&opts)
return shouldRetry(resp, err)
})
if err != nil {
return errors.Wrap(err, "DirMove MOVE call failed")
}
return nil
}
// Hashes returns the supported hash sets.
func (f *Fs) Hashes() fs.HashSet {
return fs.HashSet(fs.HashNone)
}
// ------------------------------------------------------------
// Fs returns the parent Fs
func (o *Object) Fs() fs.Info {
return o.fs
}
// Return a string version
func (o *Object) String() string {
if o == nil {
return "<nil>"
}
return o.remote
}
// Remote returns the remote path
func (o *Object) Remote() string {
return o.remote
}
// Hash returns the SHA-1 of an object returning a lowercase hex string
func (o *Object) Hash(t fs.HashType) (string, error) {
if t != fs.HashSHA1 {
return "", fs.ErrHashUnsupported
}
return o.sha1, nil
}
// Size returns the size of an object in bytes
func (o *Object) Size() int64 {
err := o.readMetaData()
if err != nil {
fs.Logf(o, "Failed to read metadata: %v", err)
return 0
}
return o.size
}
// setMetaData sets the metadata from info
func (o *Object) setMetaData(info *api.Prop) (err error) {
o.hasMetaData = true
o.size = info.Size
o.modTime = time.Time(info.Modified)
return nil
}
// readMetaData gets the metadata if it hasn't already been fetched
//
// it also sets the info
func (o *Object) readMetaData() (err error) {
if o.hasMetaData {
return nil
}
info, err := o.fs.readMetaDataForPath(o.remote)
if err != nil {
return err
}
return o.setMetaData(info)
}
// ModTime returns the modification time of the object
//
// It attempts to read the objects mtime and if that isn't present the
// LastModified returned in the http headers
func (o *Object) ModTime() time.Time {
err := o.readMetaData()
if err != nil {
fs.Logf(o, "Failed to read metadata: %v", err)
return time.Now()
}
return o.modTime
}
// SetModTime sets the modification time of the local fs object
func (o *Object) SetModTime(modTime time.Time) error {
return fs.ErrorCantSetModTime
}
// Storable returns a boolean showing whether this object storable
func (o *Object) Storable() bool {
return true
}
// Open an object for read
func (o *Object) Open(options ...fs.OpenOption) (in io.ReadCloser, err error) {
var resp *http.Response
opts := rest.Opts{
Method: "GET",
Path: o.filePath(),
Options: options,
}
err = o.fs.pacer.Call(func() (bool, error) {
resp, err = o.fs.srv.Call(&opts)
return shouldRetry(resp, err)
})
if err != nil {
return nil, err
}
return resp.Body, err
}
// Update the object with the contents of the io.Reader, modTime and size
//
// If existing is set then it updates the object rather than creating a new one
//
// The new object may have been created if an error is returned
func (o *Object) Update(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (err error) {
err = o.fs.mkParentDir(o.filePath())
if err != nil {
return errors.Wrap(err, "Update mkParentDir failed")
}
size := src.Size()
var resp *http.Response
opts := rest.Opts{
Method: "PUT",
Path: o.filePath(),
Body: in,
NoResponse: true,
ContentLength: &size, // FIXME this isn't necessary with owncloud - See https://github.com/nextcloud/nextcloud-snap/issues/365
}
if o.fs.useOCMtime {
opts.ExtraHeaders = map[string]string{
"X-OC-Mtime": fmt.Sprintf("%f", float64(src.ModTime().UnixNano())/1E9),
}
}
err = o.fs.pacer.CallNoRetry(func() (bool, error) {
resp, err = o.fs.srv.Call(&opts)
return shouldRetry(resp, err)
})
if err != nil {
return err
}
// read metadata from remote
o.hasMetaData = false
return o.readMetaData()
}
// Remove an object
func (o *Object) Remove() error {
opts := rest.Opts{
Method: "DELETE",
Path: o.filePath(),
NoResponse: true,
}
return o.fs.pacer.Call(func() (bool, error) {
resp, err := o.fs.srv.Call(&opts)
return shouldRetry(resp, err)
})
}
// Check the interfaces are satisfied
var (
_ fs.Fs = (*Fs)(nil)
_ fs.Purger = (*Fs)(nil)
_ fs.PutStreamer = (*Fs)(nil)
_ fs.Copier = (*Fs)(nil)
_ fs.Mover = (*Fs)(nil)
_ fs.DirMover = (*Fs)(nil)
_ fs.Object = (*Object)(nil)
)