Implement streaming methods for sftp backend

This commit is contained in:
Alexander Neumann 2015-02-11 19:55:11 +01:00
parent 0a45ec1d3a
commit fdbe2f0c2d
1 changed files with 65 additions and 0 deletions

View File

@ -332,6 +332,54 @@ func (r *SFTP) Create(t Type, data []byte) (ID, error) {
return id, nil
}
// CreateFrom reads content from rd and stores it as type t. Returned is the
// storage ID. If the blob is already present, returns ErrAlreadyPresent and
// the blob's ID.
func (r *SFTP) CreateFrom(t Type, rd io.Reader) (ID, error) {
// TODO: make sure that tempfile is removed upon error
// check hash while writing
hr := NewHashingReader(rd, newHash())
// create tempfile in backend
filename, file, err := r.tempFile()
if err != nil {
return nil, err
}
// write data to tempfile
_, err = io.Copy(file, hr)
if err != nil {
return nil, err
}
err = file.Close()
if err != nil {
return nil, err
}
// get ID
id := ID(hr.Sum(nil))
// check for duplicate ID
res, err := r.Test(t, id)
if err != nil {
return nil, arrar.Annotate(err, "test for presence")
}
if res {
return id, ErrAlreadyPresent
}
// rename file
err = r.renameFile(filename, t, id)
if err != nil {
return nil, err
}
return id, nil
}
// Construct path for given Type and ID.
func (r *SFTP) filename(t Type, id ID) string {
return filepath.Join(r.dirname(t, id), id.String())
@ -365,6 +413,23 @@ func (r *SFTP) Get(t Type, id ID) ([]byte, error) {
return buf, nil
}
// GetReader returns a reader that yields the content stored under the given
// ID. The content is not verified. The reader should be closed after draining
// it.
func (r *SFTP) GetReader(t Type, id ID) (io.ReadCloser, error) {
if id == nil {
return nil, errors.New("unable to load nil ID")
}
// try to open file
file, err := r.c.Open(r.filename(t, id))
if err != nil {
return nil, err
}
return file, nil
}
// Test returns true if a blob of the given type and ID exists in the backend.
func (r *SFTP) Test(t Type, id ID) (bool, error) {
file, err := r.c.Open(r.filename(t, id))