Report sftp_error when write fails (#216)

* Report sftp_error when write fails

* sftp_get: write bytes directly, don't expect them to be unicode

* Change _get_sftp_error_str to actually return strs

docs/changelog-fragments/216.bugfix.rst

@@ -0,0 +1 @@
+Changed ``sftp.sftp_get`` to write files as bytes rather than assuming files are valid UTF8 -- by :user:`Qalthos`

docs/changelog-fragments/216.misc.rst

@@ -0,0 +1 @@
+Added additional details when SFTP write errors are raised -- by :user:`Qalthos`

src/pylibsshext/sftp.pyx

@@ -62,15 +62,20 @@ cdef class SFTP:
 
  rf = sftp.sftp_open(self._libssh_sftp_session, remote_file_b, O_WRONLY | O_CREAT | O_TRUNC, sftp.S_IRWXU)
  if rf is NULL:
- raise LibsshSFTPException("Opening remote file [%s] for write failed with error [%s]" % (remote_file, MSG_MAP.get(self._get_sftp_error_str())))
+ raise LibsshSFTPException("Opening remote file [%s] for write failed with error [%s]" % (remote_file, self._get_sftp_error_str()))
  buffer = f.read(1024)
 
  while buffer != b"":
  length = len(buffer)
  written = sftp.sftp_write(rf, PyBytes_AS_STRING(buffer), length)
  if written != length:
  sftp.sftp_close(rf)
- raise LibsshSFTPException("Writing to remote file [%s] failed" % remote_file)
+ raise LibsshSFTPException(
+ "Writing to remote file [%s] failed with error [%s]" % (
+ remote_file,
+ self._get_sftp_error_str(),
+ )
+ )
  buffer = f.read(1024)
  sftp.sftp_close(rf)
 
@@ -84,7 +89,7 @@ cdef class SFTP:
 
  rf = sftp.sftp_open(self._libssh_sftp_session, remote_file_b, O_RDONLY, sftp.S_IRWXU)
  if rf is NULL:
- raise LibsshSFTPException("Opening remote file [%s] for read failed with error [%s]" % (remote_file, MSG_MAP.get(self._get_sftp_error_str())))
+ raise LibsshSFTPException("Opening remote file [%s] for read failed with error [%s]" % (remote_file, self._get_sftp_error_str()))
 
  while True:
  file_data = sftp.sftp_read(rf, <void *>read_buffer, sizeof(char) * 1024)
@@ -93,16 +98,16 @@ cdef class SFTP:
  elif file_data < 0:
  sftp.sftp_close(rf)
  raise LibsshSFTPException("Reading data from remote file [%s] failed with error [%s]"
- % (remote_file, MSG_MAP.get(self._get_sftp_error_str())))
+ % (remote_file, self._get_sftp_error_str()))
 
- with open(local_file, 'w+') as f:
- bytes_wrote = f.write(read_buffer[:file_data].decode('utf-8'))
- if bytes_wrote and file_data != bytes_wrote:
+ with open(local_file, 'wb+') as f:
+ bytes_written = f.write(read_buffer[:file_data])
+ if bytes_written and file_data != bytes_written:
  sftp.sftp_close(rf)
  raise LibsshSFTPException("Number of bytes [%s] read from remote file [%s]"
  " does not match number of bytes [%s] written to local file [%s]"
  " due to error [%s]"
- % (file_data, remote_file, bytes_wrote, local_file, MSG_MAP.get(self._get_sftp_error_str())))
+ % (file_data, remote_file, bytes_written, local_file, self._get_sftp_error_str()))
  sftp.sftp_close(rf)
 
  def close(self):
@@ -111,4 +116,7 @@ cdef class SFTP:
  self._libssh_sftp_session = NULL
 
  def _get_sftp_error_str(self):
- return sftp.sftp_get_error(self._libssh_sftp_session)
+ error = sftp.sftp_get_error(self._libssh_sftp_session)
+ if error in MSG_MAP and error != sftp.SSH_FX_FAILURE:
+ return MSG_MAP[error]
+ return "Generic failure: %s" % self.session._get_session_error_str()