96 lines
2.0 KiB
Go
96 lines
2.0 KiB
Go
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package media
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import (
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"context"
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"errors"
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"io"
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"os"
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"path/filepath"
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)
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// Local stores objects as files under a base directory.
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type Local struct {
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dir string
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}
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// NewLocal creates a Local store rooted at dir, creating it if needed.
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func NewLocal(dir string) (*Local, error) {
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if err := os.MkdirAll(dir, 0o750); err != nil {
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return nil, err
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}
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return &Local{dir: dir}, nil
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}
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func (l *Local) resolve(key string) (string, error) {
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clean := filepath.Clean(filepath.Join(l.dir, key))
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if !hasPrefix(clean, l.dir) {
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return "", errors.New("media: invalid storage key")
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}
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return clean, nil
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}
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// Save writes the stream to disk atomically under the base directory.
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func (l *Local) Save(_ context.Context, key string, r io.Reader) error {
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path, err := l.resolve(key)
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if err != nil {
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return err
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}
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if err := os.MkdirAll(filepath.Dir(path), 0o750); err != nil {
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return err
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}
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tmp, err := os.CreateTemp(filepath.Dir(path), ".upload-*")
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if err != nil {
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return err
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}
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defer os.Remove(tmp.Name())
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if _, err := io.Copy(tmp, r); err != nil {
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tmp.Close()
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return err
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}
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if err := tmp.Close(); err != nil {
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return err
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}
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return os.Rename(tmp.Name(), path)
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}
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// Open returns a reader for the object or ErrNotFound.
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func (l *Local) Open(_ context.Context, key string) (io.ReadCloser, error) {
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path, err := l.resolve(key)
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if err != nil {
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return nil, err
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}
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f, err := os.Open(path)
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if err != nil {
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if os.IsNotExist(err) {
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return nil, ErrNotFound
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}
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return nil, err
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}
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return f, nil
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}
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// Delete removes the object; missing objects are not an error.
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func (l *Local) Delete(_ context.Context, key string) error {
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path, err := l.resolve(key)
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if err != nil {
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return err
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}
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if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
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return err
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}
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return nil
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}
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func hasPrefix(p, dir string) bool {
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rel, err := filepath.Rel(dir, p)
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if err != nil {
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return false
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}
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return rel != ".." && !startsWithDotDot(rel)
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}
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func startsWithDotDot(rel string) bool {
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return len(rel) >= 3 && rel[0] == '.' && rel[1] == '.' && (rel[2] == '/' || rel[2] == '\\')
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}
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