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# Copyright (C) 2003-2015, Stefan Schwarzer <sschwarzer@sschwarzer.net>
# and ftputil contributors (see `doc/contributors.txt`)
# See the file LICENSE for licensing terms.
"""
ftputil.file - support for file-like objects on FTP servers
"""
from __future__ import print_function
from __future__ import unicode_literals
import io
import ftputil.compat
import ftputil.error
import ftputil.socket_file_adapter
# This module shouldn't be used by clients of the ftputil library.
__all__ = []
class FTPFile(object):
"""
Represents a file-like object associated with an FTP host. File
and socket are closed appropriately if the `close` method is
called.
"""
# Set timeout in seconds when closing file connections (see ticket #51).
_close_timeout = 5
def __init__(self, host):
"""Construct the file(-like) object."""
self._host = host
# pylint: disable=protected-access
self._session = host._session
# The file is still closed.
self.closed = True
self._conn = None
self._fobj = None
def _open(self, path, mode, buffering=None, encoding=None, errors=None,
newline=None, rest=None):
"""
Open the remote file with given path name and mode.
Contrary to the `open` builtin, this method returns `None`,
instead this file object is modified in-place.
"""
# We use the same arguments as in `io.open`.
# pylint: disable=too-many-arguments
#
# `buffering` argument isn't used at this time.
# pylint: disable=unused-argument
#
# Python 3's `socket.makefile` supports the same interface as
# the new `open` builtin, but Python 2 supports only a mode,
# but doesn't return an object with the proper interface to
# wrap it in `io.TextIOWrapper`.
#
# Therefore, to make the code work on Python 2 _and_ 3, use
# `socket.makefile` to always create a binary file and under
# Python 2 wrap it in an adapter class.
#
# Check mode.
if "a" in mode:
raise ftputil.error.FTPIOError("append mode not supported")
if mode not in ("r", "rb", "rt", "w", "wb", "wt"):
raise ftputil.error.FTPIOError("invalid mode '{0}'".format(mode))
if "b" in mode and "t" in mode:
# Raise a `ValueError` like Python would.
raise ValueError("can't have text and binary mode at once")
# Convenience variables
is_binary_mode = "b" in mode
is_read_mode = "r" in mode
# `rest` is only allowed for binary mode.
if (not is_binary_mode) and (rest is not None):
raise ftputil.error.CommandNotImplementedError(
"`rest` argument can't be used for text files")
# Always use binary mode (see comments above).
transfer_type = "I"
command = "TYPE {0}".format(transfer_type)
with ftputil.error.ftplib_error_to_ftp_io_error:
self._session.voidcmd(command)
# Make transfer command.
command_type = "RETR" if is_read_mode else "STOR"
command = "{0} {1}".format(command_type, path)
# Force to binary regardless of transfer type (see above).
makefile_mode = mode
makefile_mode = makefile_mode.replace("t", "")
if not "b" in makefile_mode:
makefile_mode += "b"
# Get connection and file object.
with ftputil.error.ftplib_error_to_ftp_io_error:
self._conn = self._session.transfercmd(command, rest)
# The file object. Under Python 3, this will already be a
# `BufferedReader` or `BufferedWriter` object.
fobj = self._conn.makefile(makefile_mode)
if ftputil.compat.python_version == 2:
BufferedIOAdapter = ftputil.socket_file_adapter.BufferedIOAdapter
if is_read_mode:
fobj = BufferedIOAdapter(fobj, is_readable=True)
else:
fobj = BufferedIOAdapter(fobj, is_writable=True)
if not is_binary_mode:
fobj = io.TextIOWrapper(fobj, encoding=encoding,
errors=errors, newline=newline)
self._fobj = fobj
# This comes last so that `close` won't try to close `FTPFile`
# objects without `_conn` and `_fobj` attributes in case of an
# error.
self.closed = False
def __iter__(self):
"""Return a file iterator."""
return self
def __next__(self):
"""
Return the next line or raise `StopIteration`, if there are
no more.
"""
# Apply implicit line ending conversion for text files.
line = self.readline()
if line:
return line
else:
raise StopIteration
# Although Python 2.6+ has the `next` builtin function already, it
# still requires iterators to have a `next` method.
next = __next__
#
# Context manager methods
#
def __enter__(self):
# Return `self`, so it can be accessed as the variable
# component of the `with` statement.
return self
def __exit__(self, exc_type, exc_val, exc_tb):
# We don't need the `exc_*` arguments here
# pylint: disable=unused-argument
self.close()
# Be explicit
return False
#
# Other attributes
#
def __getattr__(self, attr_name):
"""
Handle requests for attributes unknown to `FTPFile` objects:
delegate the requests to the contained file object.
"""
if attr_name in ("encoding flush isatty fileno read readline "
"readlines seek tell truncate name softspace "
"write writelines".split()):
return getattr(self._fobj, attr_name)
raise AttributeError(
"'FTPFile' object has no attribute '{0}'".format(attr_name))
# TODO: Implement `__dir__`? (See
# http://docs.python.org/whatsnew/2.6.html#other-language-changes )
def close(self):
"""Close the `FTPFile`."""
if self.closed:
return
# Timeout value to restore, see below.
# Statement works only before the try/finally statement,
# otherwise Python raises an `UnboundLocalError`.
old_timeout = self._session.sock.gettimeout()
try:
self._fobj.close()
self._fobj = None
with ftputil.error.ftplib_error_to_ftp_io_error:
self._conn.close()
# Set a timeout to prevent waiting until server timeout
# if we have a server blocking here like in ticket #51.
self._session.sock.settimeout(self._close_timeout)
try:
with ftputil.error.ftplib_error_to_ftp_io_error:
self._session.voidresp()
except ftputil.error.FTPIOError as exc:
# Ignore some errors, see tickets #51 and #17 at
# http://ftputil.sschwarzer.net/trac/ticket/51 and
# http://ftputil.sschwarzer.net/trac/ticket/17,
# respectively.
exc = str(exc)
error_code = exc[:3]
if exc.splitlines()[0] != "timed out" and \
error_code not in ("150", "426", "450", "451"):
raise
finally:
# Restore timeout for socket of `FTPFile`'s `ftplib.FTP`
# object in case the connection is reused later.
self._session.sock.settimeout(old_timeout)
# If something went wrong before, the file is probably
# defunct and subsequent calls to `close` won't help
# either, so we consider the file closed for practical
# purposes.
self.closed = True
def __getstate__(self):
raise TypeError("cannot serialize FTPFile object")
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