Current File : //lib/python3/dist-packages/duplicity/backends/megav3backend.py
# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4; encoding:utf-8 -*-
#
# Copyright 2020 Jose L. Domingo Lopez <github@24x7linux.com>
#
# This file is part of duplicity.
#
# Duplicity is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# Duplicity is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with duplicity; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
import os
import re
import subprocess
import duplicity.backend
from duplicity.errors import BackendException
class Megav3Backend(duplicity.backend.Backend):
"""Backend for MEGA.nz cloud storage, only one that works for accounts created since Nov. 2018
See https://github.com/megous/megatools/issues/411 for more details
This MEGA backend resorts to official tools (MEGAcmd) as available at https://mega.nz/cmd
MEGAcmd works through a single binary called "mega-cmd", which keeps state (for example,
persisting a session). Multiple "mega-*" shell wrappers (ie. "mega-ls") exist as the user
interface to "mega-cmd" and MEGA API
The full MEGAcmd User Guide can be found in the software's GitHub page below :
https://github.com/meganz/MEGAcmd/blob/master/UserGuide.md"""
def __init__(self, parsed_url):
duplicity.backend.Backend.__init__(self, parsed_url)
# Sanity check : ensure all the necessary "MEGAcmd" binaries exist
self._check_binary_exists("mega-cmd")
self._check_binary_exists("mega-exec")
self._check_binary_exists("mega-help")
self._check_binary_exists("mega-get")
self._check_binary_exists("mega-login")
self._check_binary_exists("mega-logout")
self._check_binary_exists("mega-ls")
self._check_binary_exists("mega-mkdir")
self._check_binary_exists("mega-put")
self._check_binary_exists("mega-rm")
self._check_binary_exists("mega-whoami")
# "MEGAcmd" does not use a config file, however it is handy to keep one (with the old ".megarc" format) to
# securely store the username and password
self._hostname = parsed_url.hostname
if parsed_url.username is None:
self._megarc = f"{os.getenv('HOME')}/.megav3rc"
try:
conf_file = open(self._megarc, "r")
except Exception as e:
raise BackendException(
f"No password provided in URL and MEGA configuration file for "
f"duplicity does not exist as '{self._megarc}'"
)
myvars = {}
for line in conf_file:
name, var = line.partition("=")[::2]
myvars[name.strip()] = str(var.strip())
conf_file.close()
self._username = myvars["Username"]
self._password = myvars["Password"]
else:
self._username = parsed_url.username
self._password = parsed_url.password
no_logout_option = parsed_url.query_args.get("no_logout", [])
self._no_logout = (len(no_logout_option) > 0) and (no_logout_option[0].lower() in ["1", "yes", "true"])
self.ensure_mega_cmd_running()
# Remote folder ("MEGAcmd" no longer shows "Root/" at the top of the hierarchy)
self._folder = f"/{parsed_url.path[1:]}"
# Only create the remote folder if it doesn't exist yet
self.mega_login()
cmd = ["mega-ls", self._folder]
try:
self.subprocess_popen(cmd)
except Exception as e:
self._makedir(self._folder)
def _check_binary_exists(self, cmd):
"""Checks that a specified command exists in the running user command path"""
try:
# Ignore the output, as we only need the return code
subprocess.check_output(["which", cmd])
except Exception as e:
raise BackendException(
f"Command '{cmd}' not found, make sure 'MEGAcmd' tools (https://mega.nz/cmd) is properly installed "
f"and in the running user command path"
)
def ensure_mega_cmd_running(self):
"""Trigger any mega command to ensure mega-cmd server is running"""
try:
subprocess.run(
"mega-help",
stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL,
).check_returncode()
except Exception:
raise BackendException("Cannot execute mega command")
def _makedir(self, path):
"""Creates a remote directory (recursively if necessary)"""
self.mega_login()
cmd = ["mega-mkdir", "-p", path]
try:
self.subprocess_popen(cmd)
except Exception as e:
error_str = str(e)
if "Folder already exists" in error_str:
raise BackendException(
f"Folder '{path}' could not be created on MEGA because it already exists. "
f"Use another path or remove the folder in MEGA manually"
)
else:
raise BackendException(f"Folder '{path}' could not be created, reason : '{e}'")
def _put(self, source_path, remote_filename):
"""Uploads file to the specified remote folder (tries to delete it first to make
sure the new one can be uploaded)"""
try:
self.delete(remote_filename.decode())
except Exception:
pass
self.upload(
local_file=source_path.get_canonical().decode(),
remote_file=remote_filename.decode(),
)
def _get(self, remote_filename, local_path):
"""Downloads file from the specified remote path"""
self.download(
remote_file=remote_filename.decode(),
local_file=local_path.name.decode(),
)
def _list(self):
"""Lists files in the specified remote path"""
return self.folder_contents(files_only=True)
def _delete(self, filename):
"""Deletes file from the specified remote path"""
self.delete(remote_file=filename.decode())
def _close(self):
"""Function called when backend is done being used"""
if not self._no_logout:
cmd = ["mega-logout"]
self.subprocess_popen(cmd)
cmd = ["mega-exec", "exit"]
self.subprocess_popen(cmd)
def mega_login(self):
"""Helper function to check existing session exists"""
# Abort if command doesn't return in a reasonable time (somehow "mega-session" sometimes
# doesn't return), and create session if one doesn't exist yet
try:
result = subprocess.run(
"mega-whoami",
timeout=30,
capture_output=True,
)
result.check_returncode()
current_username = result.stdout.decode().split(":")[-1].strip()
if current_username != self._username:
raise Exception("Username is not match")
except subprocess.TimeoutExpired:
self._close()
raise BackendException("Timed out while trying to determine if a MEGA session exists")
except Exception as e:
if self._password is None:
self._password = self.get_password()
cmd = ["mega-login", self._username, self._password]
try:
subprocess.run(
cmd,
stderr=subprocess.DEVNULL,
).check_returncode()
except Exception as e:
self._close()
raise BackendException(f"Could not log in to MEGA, error : '{e}'")
def folder_contents(self, files_only=False):
"""Lists contents of a remote MEGA path, optionally ignoring subdirectories"""
cmd = ["mega-ls", "-l", self._folder]
self.mega_login()
files = subprocess.check_output(cmd)
files = files.decode().split("\n")
# Optionally ignore directories
if files_only:
files = [f.split()[5] for f in files if re.search("^-", f)]
return files
def download(self, remote_file, local_file):
"""Downloads a file from a remote MEGA path"""
cmd = ["mega-get", f"{self._folder}/{remote_file}", local_file]
self.mega_login()
self.subprocess_popen(cmd)
def upload(self, local_file, remote_file):
"""Uploads a file to a remote MEGA path"""
cmd = ["mega-put", local_file, f"{self._folder}/{remote_file}"]
self.mega_login()
try:
self.subprocess_popen(cmd)
except Exception as e:
error_str = str(e)
if "Reached storage quota" in error_str:
raise BackendException(
f"MEGA account over quota, could not write file : '{remote_file}' . "
f"Upgrade your storage at https://mega.nz/pro or remove some data."
)
else:
raise BackendException(f"Failed writing file '{remote_file}' to MEGA, reason : '{e}'")
def delete(self, remote_file):
"""Deletes a file from a remote MEGA path"""
cmd = ["mega-rm", "-f", f"{self._folder}/{remote_file}"]
self.mega_login()
self.subprocess_popen(cmd)
duplicity.backend.register_backend("megav3", Megav3Backend)
duplicity.backend.uses_netloc.extend(["megav3"])
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