Source code for

# -*- coding: utf-8 -*-
from __future__ import absolute_import, print_function, division

import logging
import sys
from contextlib import contextmanager

from petl.compat import PY3
from import register_reader, register_writer, get_reader, get_writer

logger = logging.getLogger(__name__)

# region RemoteSource

[docs]class RemoteSource(object): """Read or write directly from files in remote filesystems. This source handles many filesystems that are selected based on the protocol passed in the `url` argument. The url should be specified in `to..()` and `from...()` functions. E.g.:: >>> import petl as etl >>> >>> def example_s3(): ... url = 's3://mybucket/prefix/to/myfilename.csv' ... data = b'foo,bar\\na,1\\nb,2\\nc,2\\n' ... ... etl.tocsv(data, url) ... tbl = etl.fromcsv(url) ... >>> example_s3() # doctest: +SKIP +-----+-----+ | foo | bar | +=====+=====+ | 'a' | '1' | +-----+-----+ | 'b' | '2' | +-----+-----+ | 'c' | '2' | +-----+-----+ This source uses `fsspec`_ to provide the data transfer with the remote filesystem. Check the `Built-in Implementations <fs_builtin>`_ for available remote implementations. Some filesystem can use `URL chaining <fs_chain>`_ for compound I/O. .. note:: For working this source require `fsspec`_ to be installed, e.g.:: $ pip install fsspec Some remote filesystems require aditional packages to be installed. Check `Known Implementations <fs_known>`_ for checking what packages need to be installed, e.g.:: $ pip install s3fs # AWS S3 $ pip install gcsfs # Google Cloud Storage $ pip install adlfs # Azure Blob service $ pip install paramiko # SFTP $ pip install requests # HTTP, github .. versionadded:: 1.6.0 .. _fsspec: .. _fs_builtin: .. _fs_known: .. _fs_chain: """ def __init__(self, url, **kwargs): self.url = url self.kwargs = kwargs def open_file(self, mode="rb"): import fsspec # auto_mkdir=True can fail in some filesystems or without permission for full path # E.g: s3fs tries to create a bucket when writing into a folder does not exists fs =, mode=mode, compression='infer', auto_mkdir=False, **self.kwargs) return fs @contextmanager def open(self, mode="rb"): mode2 = mode[:1] + r"b" # python2 fs = self.open_file(mode=mode2) with fs as source: yield source
# registering filesystems with packages installed def _register_filesystems(only_available=False): """Search for python packages supporting remote filesystems.""" from fsspec.registry import known_implementations impls = known_implementations.items() r = w = 0 for protocol, spec in impls: missing_deps = "err" in spec if missing_deps: emsg = "# WARN: fsspec {} unavailable: {}".format(protocol, spec["err"]) logger.debug(emsg) if only_available: # otherwise foward the exception on first use when the # handler can show what package is missing continue # when missing a package for fsspec use the available source in petl # E.g: fsspec requires `requests` package installed for handling http and https reader = get_reader(protocol) if not missing_deps or reader is None: register_reader(protocol, RemoteSource) r += 1 writer = get_writer(protocol) if not missing_deps or writer is None: register_writer(protocol, RemoteSource) w += 1 dlog = "# fsspec: registered %s remote readers and %s remote writers" logger.debug(dlog, r, w) def _try_register_filesystems(): try: import fsspec except ImportError: logger.debug("# Missing fsspec package. Install with: pip install fsspec") else: try: _register_filesystems() except Exception as ex: raise Exception("# ERROR: failed to register fsspec filesystems", ex) if PY3: _try_register_filesystems() # endregion # region SMBSource
[docs]class SMBSource(object): """Downloads or uploads to Windows and Samba network drives. E.g.:: >>> def example_smb(): ... import petl as etl ... url = 'smb://user:password@server/share/folder/file.csv' ... data = b'foo,bar\\na,1\\nb,2\\nc,2\\n' ... etl.tocsv(data, url) ... tbl = etl.fromcsv(url) ... >>> example_smb() # doctest: +SKIP +-----+-----+ | foo | bar | +=====+=====+ | 'a' | '1' | +-----+-----+ | 'b' | '2' | +-----+-----+ | 'c' | '2' | +-----+-----+ The argument `url` (str) must have a URI with format: `smb://workgroup;user:password@server:port/share/folder/file.csv`. Note that you need to pass in a valid hostname or IP address for the host component of the URL. Do not use the Windows/NetBIOS machine name for the host component. The first component of the path in the URL points to the name of the shared folder. Subsequent path components will point to the directory/folder/file. .. note:: For working this source require `smbprotocol`_ to be installed, e.g.:: $ pip install smbprotocol[kerberos] .. versionadded:: 1.5.0 .. _smbprotocol: """ def __init__(self, url, **kwargs): self.url = url self.kwargs = kwargs @contextmanager def open(self, mode="rb"): mode2 = mode[:1] + r"b" # python2 source = _open_file_smbprotocol(self.url, mode=mode2, **self.kwargs) try: yield source finally: source.close()
def _open_file_smbprotocol(url, mode="rb", **kwargs): _domain, host, port, user, passwd, server_path = _parse_smb_url(url) import smbclient try: # register the server with explicit credentials if user: smbclient.register_session( host, username=user, password=passwd, port=port ) # Read an existing file as bytes mode2 = mode[:1] + r"b" filehandle = smbclient.open_file(server_path, mode=mode2, **kwargs) return filehandle except Exception as ex: raise ConnectionError("SMB error: %s" % ex).with_traceback(sys.exc_info()[2]) def _parse_smb_url(url): e = "SMB url must be smb://workgroup;user:password@server:port/share/folder/file.txt: " if not url: raise ValueError("SMB error: no host given") if not url.startswith("smb://"): raise ValueError(e + url) if PY3: from urllib.parse import urlparse else: from urlparse import urlparse parsed = urlparse(url) if not parsed.path: raise ValueError(e + url) unc_path = parsed.path.replace("/", "\\") server_path = "\\\\{}{}".format(parsed.hostname, unc_path) if not parsed.username: domain = None username = None elif ";" in parsed.username: domain, username = parsed.username.split(";") else: domain, username = None, parsed.username port = 445 if not parsed.port else int(parsed.port) return domain, parsed.hostname, port, username, parsed.password, server_path register_reader("smb", SMBSource) register_writer("smb", SMBSource) # endregion