# Copyright (c) 2018 The Pooch Developers.
# Distributed under the terms of the BSD 3-Clause License.
# SPDX-License-Identifier: BSD-3-Clause
#
# This code is part of the Fatiando a Terra project (https://www.fatiando.org)
#
"""
The classes that actually handle the downloads.
"""
import sys
import ftplib
import requests
from .utils import parse_url
try:
from tqdm import tqdm
except ImportError:
tqdm = None
try:
import paramiko
except ImportError:
paramiko = None
def choose_downloader(url):
"""
Choose the appropriate downloader for the given URL based on the protocol.
Parameters
----------
url : str
A URL (including protocol).
Returns
-------
downloader
A downloader class (either :class:`pooch.HTTPDownloader`,
:class:`pooch.FTPDownloader`, or :class: `pooch.SFTPDownloader`).
Examples
--------
>>> downloader = choose_downloader("http://something.com")
>>> print(downloader.__class__.__name__)
HTTPDownloader
>>> downloader = choose_downloader("https://something.com")
>>> print(downloader.__class__.__name__)
HTTPDownloader
>>> downloader = choose_downloader("ftp://something.com")
>>> print(downloader.__class__.__name__)
FTPDownloader
"""
known_downloaders = {
"ftp": FTPDownloader,
"https": HTTPDownloader,
"http": HTTPDownloader,
"sftp": SFTPDownloader,
}
parsed_url = parse_url(url)
if parsed_url["protocol"] not in known_downloaders:
raise ValueError(
f"Unrecognized URL protocol '{parsed_url['protocol']}' in '{url}'. "
f"Must be one of {known_downloaders.keys()}."
)
downloader = known_downloaders[parsed_url["protocol"]]()
return downloader
[docs]class HTTPDownloader: # pylint: disable=too-few-public-methods
"""
Download manager for fetching files over HTTP/HTTPS.
When called, downloads the given file URL into the specified local file.
Uses the :mod:`requests` library to manage downloads.
Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to customize
the download of files (for example, to use authentication or print a
progress bar).
Parameters
----------
progressbar : bool or an arbitrary progress bar object
If True, will print a progress bar of the download to standard error
(stderr). Requires `tqdm <https://github.com/tqdm/tqdm>`__ to be
installed. Alternatively, an arbitrary progress bar object can be
passed. See :ref:`custom-progressbar` for details.
chunk_size : int
Files are streamed *chunk_size* bytes at a time instead of loading
everything into memory at one. Usually doesn't need to be changed.
**kwargs
All keyword arguments given when creating an instance of this class
will be passed to :func:`requests.get`.
Examples
--------
Download one of the data files from the Pooch repository:
>>> import os
>>> from pooch import __version__, check_version
>>> url = "https://github.com/fatiando/pooch/raw/{}/data/tiny-data.txt"
>>> url = url.format(check_version(__version__))
>>> downloader = HTTPDownloader()
>>> # Not using with Pooch.fetch so no need to pass an instance of Pooch
>>> downloader(url=url, output_file="tiny-data.txt", pooch=None)
>>> os.path.exists("tiny-data.txt")
True
>>> with open("tiny-data.txt") as f:
... print(f.read().strip())
# A tiny data file for test purposes only
1 2 3 4 5 6
>>> os.remove("tiny-data.txt")
Authentication can be handled by passing a user name and password to
:func:`requests.get`. All arguments provided when creating an instance of
the class are forwarded to :func:`requests.get`. We'll use
``auth=(username, password)`` to use basic HTTPS authentication. The
https://httpbin.org website allows us to make a fake a login request using
whatever username and password we provide to it:
>>> user = "doggo"
>>> password = "goodboy"
>>> # httpbin will ask for the user and password we provide in the URL
>>> url = f"https://httpbin.org/basic-auth/{user}/{password}"
>>> # Trying without the login credentials causes an error
>>> downloader = HTTPDownloader()
>>> try:
... downloader(url=url, output_file="tiny-data.txt", pooch=None)
... except Exception:
... print("There was an error!")
There was an error!
>>> # Pass in the credentials to HTTPDownloader
>>> downloader = HTTPDownloader(auth=(user, password))
>>> downloader(url=url, output_file="tiny-data.txt", pooch=None)
>>> with open("tiny-data.txt") as f:
... for line in f:
... print(line.rstrip())
{
"authenticated": true,
"user": "doggo"
}
>>> os.remove("tiny-data.txt")
"""
def __init__(self, progressbar=False, chunk_size=1024, **kwargs):
self.kwargs = kwargs
self.progressbar = progressbar
self.chunk_size = chunk_size
if self.progressbar is True and tqdm is None:
raise ValueError("Missing package 'tqdm' required for progress bars.")
[docs] def __call__(self, url, output_file, pooch):
"""
Download the given URL over HTTP to the given output file.
Uses :func:`requests.get`.
Parameters
----------
url : str
The URL to the file you want to download.
output_file : str or file-like object
Path (and file name) to which the file will be downloaded.
pooch : :class:`~pooch.Pooch`
The instance of :class:`~pooch.Pooch` that is calling this method.
"""
kwargs = self.kwargs.copy()
kwargs.setdefault("stream", True)
ispath = not hasattr(output_file, "write")
if ispath:
output_file = open(output_file, "w+b")
try:
response = requests.get(url, **kwargs)
response.raise_for_status()
content = response.iter_content(chunk_size=self.chunk_size)
total = int(response.headers.get("content-length", 0))
if self.progressbar is True:
# Need to use ascii characters on Windows because there isn't
# always full unicode support
# (see https://github.com/tqdm/tqdm/issues/454)
use_ascii = bool(sys.platform == "win32")
progress = tqdm(
total=total,
ncols=79,
ascii=use_ascii,
unit="B",
unit_scale=True,
leave=True,
)
elif self.progressbar:
progress = self.progressbar
progress.total = total
for chunk in content:
if chunk:
output_file.write(chunk)
output_file.flush()
if self.progressbar:
# Use the chunk size here because chunk may be much
# larger if the data are decompressed by requests after
# reading (happens with text files).
progress.update(self.chunk_size)
# Make sure the progress bar gets filled even if the actual number
# is chunks is smaller than expected. This happens when streaming
# text files that are compressed by the server when sending (gzip).
# Binary files don't experience this.
if self.progressbar:
progress.reset()
progress.update(total)
progress.close()
finally:
if ispath:
output_file.close()
[docs]class FTPDownloader: # pylint: disable=too-few-public-methods
"""
Download manager for fetching files over FTP.
When called, downloads the given file URL into the specified local file.
Uses the :mod:`ftplib` module to manage downloads.
Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to customize
the download of files (for example, to use authentication or print a
progress bar).
Parameters
----------
port : int
Port used for the FTP connection.
username : str
User name used to login to the server. Only needed if the server
requires authentication (i.e., no anonymous FTP).
password : str
Password used to login to the server. Only needed if the server
requires authentication (i.e., no anonymous FTP). Use the empty string
to indicate no password is required.
account : str
Some servers also require an "account" name for authentication.
timeout : int
Timeout in seconds for ftp socket operations, use None to mean no
timeout.
progressbar : bool
If True, will print a progress bar of the download to standard error
(stderr). Requires `tqdm <https://github.com/tqdm/tqdm>`__ to be
installed. **Custom progress bars are not yet supported.**
chunk_size : int
Files are streamed *chunk_size* bytes at a time instead of loading
everything into memory at one. Usually doesn't need to be changed.
"""
def __init__(
self,
port=21,
username="anonymous",
password="",
account="",
timeout=None,
progressbar=False,
chunk_size=1024,
):
self.port = port
self.username = username
self.password = password
self.account = account
self.timeout = timeout
self.progressbar = progressbar
self.chunk_size = chunk_size
if self.progressbar is True and tqdm is None:
raise ValueError("Missing package 'tqdm' required for progress bars.")
[docs] def __call__(self, url, output_file, pooch):
"""
Download the given URL over FTP to the given output file.
Parameters
----------
url : str
The URL to the file you want to download.
output_file : str or file-like object
Path (and file name) to which the file will be downloaded.
pooch : :class:`~pooch.Pooch`
The instance of :class:`~pooch.Pooch` that is calling this method.
"""
parsed_url = parse_url(url)
ftp = ftplib.FTP(timeout=self.timeout)
ftp.connect(host=parsed_url["netloc"], port=self.port)
ispath = not hasattr(output_file, "write")
if ispath:
output_file = open(output_file, "w+b")
try:
ftp.login(user=self.username, passwd=self.password, acct=self.account)
command = f"RETR {parsed_url['path']}"
if self.progressbar:
# Make sure the file is set to binary mode, otherwise we can't
# get the file size. See: https://stackoverflow.com/a/22093848
ftp.voidcmd("TYPE I")
size = int(ftp.size(parsed_url["path"]))
use_ascii = bool(sys.platform == "win32")
progress = tqdm(
total=size,
ncols=79,
ascii=use_ascii,
unit="B",
unit_scale=True,
leave=True,
)
with progress:
def callback(data):
"Update the progress bar and write to output"
progress.update(len(data))
output_file.write(data)
ftp.retrbinary(command, callback, blocksize=self.chunk_size)
else:
ftp.retrbinary(command, output_file.write, blocksize=self.chunk_size)
finally:
ftp.quit()
if ispath:
output_file.close()
[docs]class SFTPDownloader: # pylint: disable=too-few-public-methods
"""
Download manager for fetching files over SFTP.
When called, downloads the given file URL into the specified local file.
Requires `paramiko <https://github.com/paramiko/paramiko>`__ to be
installed.
Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to customize
the download of files (for example, to use authentication or print a
progress bar).
Parameters
----------
port : int
Port used for the SFTP connection.
username : str
User name used to login to the server. Only needed if the server
requires authentication (i.e., no anonymous SFTP).
password : str
Password used to login to the server. Only needed if the server
requires authentication (i.e., no anonymous SFTP). Use the empty
string to indicate no password is required.
timeout : int
Timeout in seconds for sftp socket operations, use None to mean no
timeout.
progressbar : bool or an arbitrary progress bar object
If True, will print a progress bar of the download to standard
error (stderr). Requires `tqdm <https://github.com/tqdm/tqdm>`__ to
be installed.
"""
def __init__(
self,
port=22,
username="anonymous",
password="",
account="",
timeout=None,
progressbar=False,
):
self.port = port
self.username = username
self.password = password
self.account = account
self.timeout = timeout
self.progressbar = progressbar
# Collect errors and raise only once so that both missing packages are
# captured. Otherwise, the user is only warned of one of them at a
# time (and we can't test properly when they are both missing).
errors = []
if self.progressbar and tqdm is None:
errors.append("Missing package 'tqdm' required for progress bars.")
if paramiko is None:
errors.append("Missing package 'paramiko' required for SFTP downloads.")
if errors:
raise ValueError(" ".join(errors))
[docs] def __call__(self, url, output_file, pooch):
"""
Download the given URL over SFTP to the given output file.
The output file must be given as a string (file name/path) and not an
open file object! Otherwise, paramiko cannot save to that file.
Parameters
----------
url : str
The URL to the file you want to download.
output_file : str
Path (and file name) to which the file will be downloaded. **Cannot
be a file object**.
pooch : :class:`~pooch.Pooch`
The instance of :class:`~pooch.Pooch` that is calling this method.
"""
parsed_url = parse_url(url)
connection = paramiko.Transport(sock=(parsed_url["netloc"], self.port))
sftp = None
try:
connection.connect(username=self.username, password=self.password)
sftp = paramiko.SFTPClient.from_transport(connection)
sftp.get_channel().settimeout = self.timeout
if self.progressbar:
size = int(sftp.stat(parsed_url["path"]).st_size)
use_ascii = bool(sys.platform == "win32")
progress = tqdm(
total=size,
ncols=79,
ascii=use_ascii,
unit="B",
unit_scale=True,
leave=True,
)
if self.progressbar:
with progress:
def callback(current, total):
"Update the progress bar and write to output"
progress.total = int(total)
progress.update(int(current - progress.n))
sftp.get(parsed_url["path"], output_file, callback=callback)
else:
sftp.get(parsed_url["path"], output_file)
finally:
connection.close()
if sftp is not None:
sftp.close()
