Source code for b2sdk.scan.folder

######################################################################
#
# File: b2sdk/scan/folder.py
#
# Copyright 2019 Backblaze Inc. All Rights Reserved.
#
# License https://www.backblaze.com/using_b2_code.html
#
######################################################################
from __future__ import annotations

import logging
import os
import platform
import re
import sys
from abc import ABCMeta, abstractmethod
from pathlib import Path
from typing import Iterator

from ..utils import fix_windows_path_limit, get_file_mtime, is_file_readable
from .exception import (
    EmptyDirectory,
    EnvironmentEncodingError,
    NotADirectory,
    UnableToCreateDirectory,
    UnsupportedFilename,
)
from .path import AbstractPath, B2Path, LocalPath
from .policies import DEFAULT_SCAN_MANAGER, ScanPoliciesManager
from .report import ProgressReport

DRIVE_MATCHER = re.compile(r"^([A-Za-z]):([/\\])")
ABSOLUTE_PATH_MATCHER = re.compile(r"^(/)|^(\\)")
RELATIVE_PATH_MATCHER = re.compile(
                           # "abc" and "xyz" represent anything, including "nothing"
    r"^(\.\.[/\\])|" +     # ../abc or ..\abc
    r"^(\.[/\\])|" +       # ./abc or .\abc
    r"([/\\]\.\.[/\\])|" + # abc/../xyz or abc\..\xyz or abc\../xyz or abc/..\xyz
    r"([/\\]\.[/\\])|" +   # abc/./xyz or abc\.\xyz or abc\./xyz or abc/.\xyz
    r"([/\\]\.\.)$|" +     # abc/.. or abc\..
    r"([/\\]\.)$|" +       # abc/. or abc\.
    r"^(\.\.)$|" +         # just ".."
    r"([/\\][/\\])|" +     # abc\/xyz or abc/\xyz or abc//xyz or abc\\xyz
    r"^(\.)$"              # just "."
)  # yapf: disable

logger = logging.getLogger(__name__)


[docs]class AbstractFolder(metaclass=ABCMeta): """ Interface to a folder full of files, which might be a B2 bucket, a virtual folder in a B2 bucket, or a directory on a local file system. Files in B2 may have multiple versions, while files in local folders have just one. """
[docs] @abstractmethod def all_files(self, reporter: ProgressReport | None, policies_manager=DEFAULT_SCAN_MANAGER) -> Iterator[AbstractPath]: """ Return an iterator over all of the files in the folder, in the order that B2 uses. It also performs filtering using policies manager. No matter what the folder separator on the local file system is, "/" is used in the returned file names. If a file is found, but does not exist (for example due to a broken symlink or a race), reporter will be informed about each such problem. :param reporter: a place to report errors :param policies_manager: a policies manager object """
[docs] @abstractmethod def folder_type(self): """ Return one of: 'b2', 'local'. :rtype: str """
[docs] @abstractmethod def make_full_path(self, file_name): """ Return the full path to the file. :param file_name: a file name :type file_name: str :rtype: str """
[docs]def join_b2_path(relative_dir_path: str | Path, file_name: str): """ Like os.path.join, but for B2 file names where the root directory is called ''. """ relative_dir_path = str(relative_dir_path) if relative_dir_path in ('', '.'): return file_name else: return relative_dir_path + '/' + file_name
[docs]class LocalFolder(AbstractFolder): """ Folder interface to a directory on the local machine. """
[docs] def __init__(self, root: str | Path): """ Initialize a new folder. :param root: path to the root of the local folder. Must be unicode. """ if isinstance(root, Path): root = str(root) if not isinstance(root, str): raise ValueError('folder path should be str or pathlib.Path: %s' % repr(root)) self.root = fix_windows_path_limit(os.path.abspath(root))
[docs] def folder_type(self): """ Return folder type. :rtype: str """ return 'local'
[docs] def all_files(self, reporter: ProgressReport | None, policies_manager=DEFAULT_SCAN_MANAGER) -> Iterator[LocalPath]: """ Yield all files. :param reporter: a place to report errors :param policies_manager: a policy manager object, default is DEFAULT_SCAN_MANAGER """ root_path = Path(self.root) yield from self._walk_relative_paths(root_path, Path(''), reporter, policies_manager)
[docs] def make_full_path(self, file_name): """ Convert a file name into an absolute path, ensure it is not outside self.root :param file_name: a file name :type file_name: str """ # Fix OS path separators file_name = file_name.replace('/', os.path.sep) # Generate the full path to the file full_path = os.path.normpath(os.path.join(self.root, file_name)) # Get the common prefix between the new full_path and self.root common_prefix = os.path.commonprefix([full_path, self.root]) # Ensure the new full_path is inside the self.root directory if common_prefix != self.root: raise UnsupportedFilename("illegal file name", full_path) return full_path
[docs] def ensure_present(self): """ Make sure that the directory exists. """ if not os.path.exists(self.root): try: os.mkdir(self.root) except OSError: raise UnableToCreateDirectory(self.root) elif not os.path.isdir(self.root): raise NotADirectory(self.root)
[docs] def ensure_non_empty(self): """ Make sure that the directory exists and is non-empty. """ self.ensure_present() if not os.listdir(self.root): raise EmptyDirectory(self.root)
def _walk_relative_paths( self, local_dir: Path, relative_dir_path: Path, reporter: ProgressReport, policies_manager: ScanPoliciesManager, visited_symlinks: set[int] | None = None, ): """ Yield a File object for each of the files anywhere under this folder, in the order they would appear in B2, unless the path is excluded by policies manager. :param local_dir: the path to the local directory that we are currently inspecting :param relative_dir_path: the path of this dir relative to the scan point, or Path('') if at scan point :param reporter: a reporter object to report errors and warnings :param policies_manager: a policies manager object :param visited_symlinks: a set of paths to symlinks that have already been visited. Using inode numbers to reduce memory usage """ # Collect the names. We do this before returning any results, because # directories need to sort as if their names end in '/'. # # With a directory containing 'a', 'a.txt', and 'a0.txt', with 'a' being # a directory containing 'b.txt', and 'c.txt', the results returned # should be: # # a.txt # a/b.txt # a/c.txt # a0.txt # # This is because in Unicode '.' comes before '/', which comes before '0'. names = [] # list of (name, local_path, relative_file_path) visited_symlinks = visited_symlinks or set() if local_dir.is_symlink(): real_path = local_dir.resolve() inode_number = real_path.stat().st_ino visited_symlinks_count = len(visited_symlinks) # Add symlink to visited_symlinks to prevent infinite symlink loops visited_symlinks.add(inode_number) # Check if set size has changed, if not, symlink has already been visited if len(visited_symlinks) == visited_symlinks_count: # Infinite symlink loop detected, report warning and skip symlink if reporter is not None: reporter.circular_symlink_skipped(str(local_dir)) return visited_symlinks.add(inode_number) for name in (x.name for x in local_dir.iterdir()): if '/' in name: raise UnsupportedFilename( "scan does not support file names that include '/'", f"{name} in dir {local_dir}" ) local_path = local_dir / name relative_file_path = join_b2_path(relative_dir_path, name) # Skip broken symlinks or other inaccessible files if not is_file_readable(str(local_path), reporter): continue if policies_manager.exclude_all_symlinks and local_path.is_symlink(): if reporter is not None: reporter.symlink_skipped(str(local_path)) continue if local_path.is_dir(): name += '/' if policies_manager.should_exclude_local_directory(str(relative_file_path)): continue # remove the leading './' from the relative path to ensure backward compatibility relative_file_path_str = str(relative_file_path) if relative_file_path_str.startswith("./"): relative_file_path_str = relative_file_path_str[2:] names.append((name, local_path, relative_file_path_str)) # Yield all of the answers. # # Sorting the list of triples puts them in the right order because 'name', # the sort key, is the first thing in the triple. for (name, local_path, relative_file_path) in sorted(names): if name.endswith('/'): yield from self._walk_relative_paths( local_path, relative_file_path, reporter, policies_manager, visited_symlinks, ) else: # Check that the file still exists and is accessible, since it can take a long time # to iterate through large folders if is_file_readable(str(local_path), reporter): file_mod_time = get_file_mtime(str(local_path)) file_size = local_path.stat().st_size local_scan_path = LocalPath( absolute_path=self.make_full_path(str(relative_file_path)), relative_path=str(relative_file_path), mod_time=file_mod_time, size=file_size, ) if policies_manager.should_exclude_local_path(local_scan_path): continue yield local_scan_path @classmethod def _handle_non_unicode_file_name(cls, name): """ Decide what to do with a name returned from os.listdir() that isn't unicode. We think that this only happens when the file name can't be decoded using the file system encoding. Just in case that's not true, we'll allow all-ascii names. """ # if it's all ascii, allow it if all(b <= 127 for b in name): return name raise EnvironmentEncodingError(repr(name), sys.getfilesystemencoding()) def __repr__(self): return f'LocalFolder({self.root})'
[docs]def b2_parent_dir(file_name): # Various Parent dir getting method have been tested, and this one seems to be the faste # After dropping python 3.9 support: refactor this use the "match" syntax try: dir_name, _ = file_name.rsplit('/', 1) except ValueError: return '' return dir_name
[docs]class B2Folder(AbstractFolder): """ Folder interface to b2. """
[docs] def __init__(self, bucket_name, folder_name, api): """ :param bucket_name: a name of the bucket :type bucket_name: str :param folder_name: a folder name :type folder_name: str :param api: an API object :type api: b2sdk.api.B2Api """ self.bucket_name = bucket_name self.folder_name = folder_name self.bucket = api.get_bucket_by_name(bucket_name) self.api = api self.prefix = self.folder_name if self.prefix and self.prefix[-1] != '/': self.prefix += '/'
[docs] def all_files( self, reporter: ProgressReport | None, policies_manager: ScanPoliciesManager = DEFAULT_SCAN_MANAGER ) -> Iterator[B2Path]: """ Yield all files. """ current_name = None last_ignored_dir = None current_versions = [] current_file_version = None for file_version in self.get_file_versions(): if current_file_version is None: current_file_version = file_version assert file_version.file_name.startswith(self.prefix) if file_version.action == 'start': continue file_name = file_version.file_name[len(self.prefix):] if last_ignored_dir is not None and file_name.startswith(last_ignored_dir): continue dir_name = b2_parent_dir(file_name) if policies_manager.should_exclude_b2_directory(dir_name): last_ignored_dir = dir_name + '/' continue else: last_ignored_dir = None if policies_manager.should_exclude_b2_file_version(file_version, file_name): continue self._validate_file_name(file_name) if current_name != file_name and current_name is not None and current_versions: yield B2Path( relative_path=current_name, selected_version=current_versions[0], all_versions=current_versions ) current_versions = [] current_name = file_name current_versions.append(file_version) if current_name is not None and current_versions: yield B2Path( relative_path=current_name, selected_version=current_versions[0], all_versions=current_versions )
[docs] def get_file_versions(self): for file_version, _ in self.bucket.ls( self.folder_name, latest_only=False, recursive=True, ): yield file_version
def _validate_file_name(self, file_name): # Do not allow relative paths in file names if RELATIVE_PATH_MATCHER.search(file_name): raise UnsupportedFilename( "scan does not support file names that include relative paths", file_name ) # Do not allow absolute paths in file names if ABSOLUTE_PATH_MATCHER.search(file_name): raise UnsupportedFilename( "scan does not support file names with absolute paths", file_name ) # On Windows, do not allow drive letters in file names if platform.system() == "Windows" and DRIVE_MATCHER.search(file_name): raise UnsupportedFilename( "scan does not support file names with drive letters", file_name )
[docs] def folder_type(self): """ Return folder type. :rtype: str """ return 'b2'
[docs] def make_full_path(self, file_name): """ Make an absolute path from a file name. :param file_name: a file name :type file_name: str """ if self.folder_name == '': return file_name else: return self.folder_name + '/' + file_name
def __str__(self): return f'B2Folder({self.bucket_name}, {self.folder_name})'