# -*- coding: utf-8 -*- # # Copyright (C) 2019 Radim Rehurek # # This code is distributed under the terms and conditions # from the MIT License (MIT). # """Implements the majority of smart_open's top-level API. The main functions are: * ``parse_uri()`` * ``open()`` """ import collections import io import locale import logging import os import os.path as P import pathlib import urllib.parse import warnings # # This module defines a function called smart_open so we cannot use # smart_open.submodule to reference to the submodules. # import smart_open.local_file as so_file import smart_open.compression as so_compression from smart_open import doctools from smart_open import transport # # For backwards compatibility and keeping old unit tests happy. # from smart_open.compression import register_compressor # noqa: F401 from smart_open.utils import check_kwargs as _check_kwargs # noqa: F401 from smart_open.utils import inspect_kwargs as _inspect_kwargs # noqa: F401 logger = logging.getLogger(__name__) DEFAULT_ENCODING = locale.getpreferredencoding(do_setlocale=False) def _sniff_scheme(uri_as_string): """Returns the scheme of the URL only, as a string.""" # # urlsplit doesn't work on Windows -- it parses the drive as the scheme... # no protocol given => assume a local file # if os.name == 'nt' and '://' not in uri_as_string: uri_as_string = 'file://' + uri_as_string return urllib.parse.urlsplit(uri_as_string).scheme def parse_uri(uri_as_string): """ Parse the given URI from a string. Parameters ---------- uri_as_string: str The URI to parse. Returns ------- collections.namedtuple The parsed URI. Notes ----- smart_open/doctools.py magic goes here """ scheme = _sniff_scheme(uri_as_string) submodule = transport.get_transport(scheme) as_dict = submodule.parse_uri(uri_as_string) # # The conversion to a namedtuple is just to keep the old tests happy while # I'm still refactoring. # Uri = collections.namedtuple('Uri', sorted(as_dict.keys())) return Uri(**as_dict) # # To keep old unit tests happy while I'm refactoring. # _parse_uri = parse_uri _builtin_open = open def open( uri, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None, ignore_ext=False, compression=None, transport_params=None, ): r"""Open the URI object, returning a file-like object. The URI is usually a string in a variety of formats. For a full list of examples, see the :func:`parse_uri` function. The URI may also be one of: - an instance of the pathlib.Path class - a stream (anything that implements io.IOBase-like functionality) Parameters ---------- uri: str or object The object to open. mode: str, optional Mimicks built-in open parameter of the same name. buffering: int, optional Mimicks built-in open parameter of the same name. encoding: str, optional Mimicks built-in open parameter of the same name. errors: str, optional Mimicks built-in open parameter of the same name. newline: str, optional Mimicks built-in open parameter of the same name. closefd: boolean, optional Mimicks built-in open parameter of the same name. Ignored. opener: object, optional Mimicks built-in open parameter of the same name. Ignored. ignore_ext: boolean, optional Disable transparent compression/decompression based on the file extension. compression: str, optional (see smart_open.compression.get_supported_compression_types) Explicitly specify the compression/decompression behavior. If you specify this parameter, then ignore_ext must not be specified. transport_params: dict, optional Additional parameters for the transport layer (see notes below). Returns ------- A file-like object. Notes ----- smart_open has several implementations for its transport layer (e.g. S3, HTTP). Each transport layer has a different set of keyword arguments for overriding default behavior. If you specify a keyword argument that is *not* supported by the transport layer being used, smart_open will ignore that argument and log a warning message. smart_open/doctools.py magic goes here See Also -------- - `Standard library reference `__ - `smart_open README.rst `__ """ logger.debug('%r', locals()) if not isinstance(mode, str): raise TypeError('mode should be a string') if compression and ignore_ext: raise ValueError('ignore_ext and compression parameters are mutually exclusive') elif compression and compression not in so_compression.get_supported_compression_types(): raise ValueError(f'invalid compression type: {compression}') elif ignore_ext: compression = so_compression.NO_COMPRESSION warnings.warn("'ignore_ext' will be deprecated in a future release", PendingDeprecationWarning) elif compression is None: compression = so_compression.INFER_FROM_EXTENSION if transport_params is None: transport_params = {} fobj = _shortcut_open( uri, mode, compression=compression, buffering=buffering, encoding=encoding, errors=errors, newline=newline, ) if fobj is not None: return fobj # # This is a work-around for the problem described in Issue #144. # If the user has explicitly specified an encoding, then assume they want # us to open the destination in text mode, instead of the default binary. # # If we change the default mode to be text, and match the normal behavior # of Py2 and 3, then the above assumption will be unnecessary. # if encoding is not None and 'b' in mode: mode = mode.replace('b', '') if isinstance(uri, pathlib.Path): uri = str(uri) explicit_encoding = encoding encoding = explicit_encoding if explicit_encoding else DEFAULT_ENCODING # # This is how we get from the filename to the end result. Decompression is # optional, but it always accepts bytes and returns bytes. # # Decoding is also optional, accepts bytes and returns text. The diagram # below is for reading, for writing, the flow is from right to left, but # the code is identical. # # open as binary decompress? decode? # filename ---------------> bytes -------------> bytes ---------> text # binary decompressed decode # try: binary_mode = _get_binary_mode(mode) except ValueError as ve: raise NotImplementedError(ve.args[0]) binary = _open_binary_stream(uri, binary_mode, transport_params) decompressed = so_compression.compression_wrapper(binary, binary_mode, compression) if 'b' not in mode or explicit_encoding is not None: decoded = _encoding_wrapper( decompressed, mode, encoding=encoding, errors=errors, newline=newline, ) else: decoded = decompressed return decoded def _get_binary_mode(mode_str): # # https://docs.python.org/3/library/functions.html#open # # The order of characters in the mode parameter appears to be unspecified. # The implementation follows the examples, just to be safe. # mode = list(mode_str) binmode = [] if 't' in mode and 'b' in mode: raise ValueError("can't have text and binary mode at once") counts = [mode.count(x) for x in 'rwa'] if sum(counts) > 1: raise ValueError("must have exactly one of create/read/write/append mode") def transfer(char): binmode.append(mode.pop(mode.index(char))) if 'a' in mode: transfer('a') elif 'w' in mode: transfer('w') elif 'r' in mode: transfer('r') else: raise ValueError( "Must have exactly one of create/read/write/append " "mode and at most one plus" ) if 'b' in mode: transfer('b') elif 't' in mode: mode.pop(mode.index('t')) binmode.append('b') else: binmode.append('b') if '+' in mode: transfer('+') # # There shouldn't be anything left in the mode list at this stage. # If there is, then either we've missed something and the implementation # of this function is broken, or the original input mode is invalid. # if mode: raise ValueError('invalid mode: %r' % mode_str) return ''.join(binmode) def _shortcut_open( uri, mode, compression, buffering=-1, encoding=None, errors=None, newline=None, ): """Try to open the URI using the standard library io.open function. This can be much faster than the alternative of opening in binary mode and then decoding. This is only possible under the following conditions: 1. Opening a local file; and 2. Compression is disabled If it is not possible to use the built-in open for the specified URI, returns None. :param str uri: A string indicating what to open. :param str mode: The mode to pass to the open function. :param str compression: The compression type selected. :returns: The opened file :rtype: file """ if not isinstance(uri, str): return None scheme = _sniff_scheme(uri) if scheme not in (transport.NO_SCHEME, so_file.SCHEME): return None local_path = so_file.extract_local_path(uri) if compression == so_compression.INFER_FROM_EXTENSION: _, extension = P.splitext(local_path) if extension in so_compression.get_supported_extensions(): return None elif compression != so_compression.NO_COMPRESSION: return None open_kwargs = {} if encoding is not None: open_kwargs['encoding'] = encoding mode = mode.replace('b', '') if newline is not None: open_kwargs['newline'] = newline # # binary mode of the builtin/stdlib open function doesn't take an errors argument # if errors and 'b' not in mode: open_kwargs['errors'] = errors return _builtin_open(local_path, mode, buffering=buffering, **open_kwargs) def _open_binary_stream(uri, mode, transport_params): """Open an arbitrary URI in the specified binary mode. Not all modes are supported for all protocols. :arg uri: The URI to open. May be a string, or something else. :arg str mode: The mode to open with. Must be rb, wb or ab. :arg transport_params: Keyword argumens for the transport layer. :returns: A named file object :rtype: file-like object with a .name attribute """ if mode not in ('rb', 'rb+', 'wb', 'wb+', 'ab', 'ab+'): # # This should really be a ValueError, but for the sake of compatibility # with older versions, which raise NotImplementedError, we do the same. # raise NotImplementedError('unsupported mode: %r' % mode) if hasattr(uri, 'read'): # simply pass-through if already a file-like # we need to return something as the file name, but we don't know what # so we probe for uri.name (e.g., this works with open() or tempfile.NamedTemporaryFile) # if the value ends with COMPRESSED_EXT, we will note it in compression_wrapper() # if there is no such an attribute, we return "unknown" - this # effectively disables any compression if not hasattr(uri, 'name'): uri.name = getattr(uri, 'name', 'unknown') return uri if not isinstance(uri, str): raise TypeError("don't know how to handle uri %s" % repr(uri)) scheme = _sniff_scheme(uri) submodule = transport.get_transport(scheme) fobj = submodule.open_uri(uri, mode, transport_params) if not hasattr(fobj, 'name'): fobj.name = uri return fobj def _encoding_wrapper(fileobj, mode, encoding=None, errors=None, newline=None): """Decode bytes into text, if necessary. If mode specifies binary access, does nothing, unless the encoding is specified. A non-null encoding implies text mode. :arg fileobj: must quack like a filehandle object. :arg str mode: is the mode which was originally requested by the user. :arg str encoding: The text encoding to use. If mode is binary, overrides mode. :arg str errors: The method to use when handling encoding/decoding errors. :returns: a file object """ logger.debug('encoding_wrapper: %r', locals()) # # If the mode is binary, but the user specified an encoding, assume they # want text. If we don't make this assumption, ignore the encoding and # return bytes, smart_open behavior will diverge from the built-in open: # # open(filename, encoding='utf-8') returns a text stream in Py3 # smart_open(filename, encoding='utf-8') would return a byte stream # without our assumption, because the default mode is rb. # if 'b' in mode and encoding is None: return fileobj if encoding is None: encoding = DEFAULT_ENCODING fileobj = io.TextIOWrapper( fileobj, encoding=encoding, errors=errors, newline=newline, write_through=True, ) return fileobj class patch_pathlib(object): """Replace `Path.open` with `smart_open.open`""" def __init__(self): self.old_impl = _patch_pathlib(open) def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): _patch_pathlib(self.old_impl) def _patch_pathlib(func): """Replace `Path.open` with `func`""" old_impl = pathlib.Path.open pathlib.Path.open = func return old_impl def smart_open( uri, mode='rb', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None, ignore_extension=False, **kwargs ): # # This is a thin wrapper of smart_open.open. It's here for backward # compatibility. It works exactly like smart_open.open when the passed # parameters are identical. Otherwise, it raises a DeprecationWarning. # # For completeness, the main differences of the old smart_open function: # # 1. Default mode was read binary (mode='rb') # 2. ignore_ext parameter was called ignore_extension # 3. Transport parameters were passed directly as kwargs # url = 'https://github.com/RaRe-Technologies/smart_open/blob/develop/MIGRATING_FROM_OLDER_VERSIONS.rst' if kwargs: raise DeprecationWarning( 'The following keyword parameters are not supported: %r. ' 'See %s for more information.' % (sorted(kwargs), url) ) message = 'This function is deprecated. See %s for more information' % url warnings.warn(message, category=DeprecationWarning) ignore_ext = ignore_extension del kwargs, url, message, ignore_extension return open(**locals()) # # Prevent failures with doctools from messing up the entire library. We don't # expect such failures, but contributed modules (e.g. new transport mechanisms) # may not be as polished. # try: doctools.tweak_open_docstring(open) doctools.tweak_parse_uri_docstring(parse_uri) except Exception as ex: logger.error( 'Encountered a non-fatal error while building docstrings (see below). ' 'help(smart_open) will provide incomplete information as a result. ' 'For full help text, see ' '.' ) logger.exception(ex)