func (p *PostgresFilesystem) Open(name string) (File, error) {
tx, err := p.db.Begin()
if err != nil {
return nil, err
}
var f pgFile
err = tx.QueryRow("SELECT file_id, size, type, digest, created_at FROM files WHERE name = $1",
name).Scan(&f.id, &f.size, &f.typ, &f.etag, &f.mtime)
if err != nil {
tx.Rollback()
if err == sql.ErrNoRows {
err = ErrNotFound
}
return nil, err
}
lo, err := pq.NewLargeObjects(tx)
if err != nil {
tx.Rollback()
return nil, err
}
f.LargeObject, err = lo.Open(f.id, pq.LargeObjectModeRead)
if err != nil {
tx.Rollback()
return nil, err
}
f.tx = tx
return &f, nil
}
func (p *PostgresFilesystem) Put(name string, r io.Reader, typ string) error {
tx, err := p.db.Begin()
if err != nil {
return err
}
var id oid.Oid
create:
err = tx.QueryRow("INSERT INTO files (name, type) VALUES ($1, $2) RETURNING file_id", name, typ).Scan(&id)
if e, ok := err.(*pq.Error); ok && e.Code.Name() == "unique_violation" {
tx.Rollback()
tx, err = p.db.Begin()
if err != nil {
return err
}
// file exists, delete it first
_, err = tx.Exec("DELETE FROM files WHERE name = $1", name)
if err != nil {
tx.Rollback()
return err
}
goto create
}
if err != nil {
tx.Rollback()
return err
}
lo, err := pq.NewLargeObjects(tx)
if err != nil {
tx.Rollback()
return err
}
obj, err := lo.Open(id, pq.LargeObjectModeWrite)
if err != nil {
tx.Rollback()
return err
}
h := sha512.New()
size, err := io.Copy(obj, io.TeeReader(r, h))
if err != nil {
tx.Rollback()
return err
}
digest := hex.EncodeToString(h.Sum(nil))
_, err = tx.Exec("UPDATE files SET size = $2, digest = $3 WHERE file_id = $1", id, size, digest)
if err != nil {
tx.Rollback()
return err
}
return tx.Commit()
}