forked from graymeta/stow
/
item.go
101 lines (83 loc) · 2.09 KB
/
item.go
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package b2
import (
"io"
"net/url"
"sync"
"time"
"gomodules.xyz/stow"
"github.com/pkg/errors"
"gopkg.in/kothar/go-backblaze.v0"
)
type item struct {
id string
name string
size int64
lastModified time.Time
bucket *backblaze.Bucket
metadata map[string]interface{}
infoOnce sync.Once
infoErr error
}
var _ stow.Item = (*item)(nil)
// ID returns this item's ID
func (i *item) ID() string {
return i.id
}
// Name returns this item's name
func (i *item) Name() string {
return i.name
}
// URL returns the stow url for this item
func (i *item) URL() *url.URL {
str, err := i.bucket.FileURL(i.name)
if err != nil {
return nil
}
url, _ := url.Parse(str)
url.Scheme = Kind
return url
}
// Metadata returns additional item metadata fields that were set when the file was uploaded
func (i *item) Metadata() (map[string]interface{}, error) {
if err := i.ensureInfo(); err != nil {
return nil, errors.Wrap(err, "retrieving item metadata")
}
return i.metadata, nil
}
// size returns the file's size, in bytes
func (i *item) Size() (int64, error) {
return i.size, nil
}
// Open downloads the item
func (i *item) Open() (io.ReadCloser, error) {
_, r, err := i.bucket.DownloadFileByName(i.name)
return r, err
}
// ETag returns an etag for an item. In this implementation we use the file's last modified timestamp
func (i *item) ETag() (string, error) {
if err := i.ensureInfo(); err != nil {
return "", errors.Wrap(err, "retreiving etag")
}
return i.lastModified.String(), nil
}
// LastMod returns the file's last modified timestamp
func (i *item) LastMod() (time.Time, error) {
if err := i.ensureInfo(); err != nil {
return time.Time{}, errors.Wrap(err, "retrieving Last Modified information of Item")
}
return i.lastModified, nil
}
func (i *item) ensureInfo() error {
if i.metadata == nil || i.lastModified.IsZero() {
i.infoOnce.Do(func() {
f, err := i.bucket.GetFileInfo(i.id)
if err != nil {
i.infoErr = err
return
}
i.lastModified = time.Unix(f.UploadTimestamp/1000, 0)
i.metadata = parseMetadata(f.FileInfo)
})
}
return i.infoErr
}