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# Copyright (c) Alibaba, Inc. and its affiliates.
import contextlib
import os
import tempfile
from abc import ABCMeta, abstractmethod
from pathlib import Path
from typing import Generator, Union
import requests
from urllib.parse import urlparse
def download_from_url(url):
result = urlparse(url)
file_path = None
if result.scheme is not None and len(result.scheme) > 0:
storage = HTTPStorage()
# bytes
data = storage.read(url)
work_dir = tempfile.TemporaryDirectory().name
if not os.path.exists(work_dir):
os.makedirs(work_dir)
file_path = os.path.join(work_dir, os.path.basename(url))
with open(file_path, "wb") as fb:
fb.write(data)
assert file_path is not None, f"failed to download: {url}"
return file_path
class Storage(metaclass=ABCMeta):
"""Abstract class of storage.
All backends need to implement two apis: ``read()`` and ``read_text()``.
``read()`` reads the file as a byte stream and ``read_text()`` reads
the file as texts.
"""
@abstractmethod
def read(self, filepath: str):
pass
@abstractmethod
def read_text(self, filepath: str):
pass
@abstractmethod
def write(self, obj: bytes, filepath: Union[str, Path]) -> None:
pass
@abstractmethod
def write_text(
self, obj: str, filepath: Union[str, Path], encoding: str = "utf-8"
) -> None:
pass
class LocalStorage(Storage):
"""Local hard disk storage"""
def read(self, filepath: Union[str, Path]) -> bytes:
"""Read data from a given ``filepath`` with 'rb' mode.
Args:
filepath (str or Path): Path to read data.
Returns:
bytes: Expected bytes object.
"""
with open(filepath, "rb") as f:
content = f.read()
return content
def read_text(self, filepath: Union[str, Path], encoding: str = "utf-8") -> str:
"""Read data from a given ``filepath`` with 'r' mode.
Args:
filepath (str or Path): Path to read data.
encoding (str): The encoding format used to open the ``filepath``.
Default: 'utf-8'.
Returns:
str: Expected text reading from ``filepath``.
"""
with open(filepath, "r", encoding=encoding) as f:
value_buf = f.read()
return value_buf
def write(self, obj: bytes, filepath: Union[str, Path]) -> None:
"""Write data to a given ``filepath`` with 'wb' mode.
Note:
``write`` will create a directory if the directory of ``filepath``
does not exist.
Args:
obj (bytes): Data to be written.
filepath (str or Path): Path to write data.
"""
dirname = os.path.dirname(filepath)
if dirname and not os.path.exists(dirname):
os.makedirs(dirname, exist_ok=True)
with open(filepath, "wb") as f:
f.write(obj)
def write_text(
self, obj: str, filepath: Union[str, Path], encoding: str = "utf-8"
) -> None:
"""Write data to a given ``filepath`` with 'w' mode.
Note:
``write_text`` will create a directory if the directory of
``filepath`` does not exist.
Args:
obj (str): Data to be written.
filepath (str or Path): Path to write data.
encoding (str): The encoding format used to open the ``filepath``.
Default: 'utf-8'.
"""
dirname = os.path.dirname(filepath)
if dirname and not os.path.exists(dirname):
os.makedirs(dirname, exist_ok=True)
with open(filepath, "w", encoding=encoding) as f:
f.write(obj)
@contextlib.contextmanager
def as_local_path(
self, filepath: Union[str, Path]
) -> Generator[Union[str, Path], None, None]:
"""Only for unified API and do nothing."""
yield filepath
class HTTPStorage(Storage):
"""HTTP and HTTPS storage."""
def read(self, url):
# TODO @wenmeng.zwm add progress bar if file is too large
r = requests.get(url)
r.raise_for_status()
return r.content
def read_text(self, url):
r = requests.get(url)
r.raise_for_status()
return r.text
@contextlib.contextmanager
def as_local_path(self, filepath: str) -> Generator[Union[str, Path], None, None]:
"""Download a file from ``filepath``.
``as_local_path`` is decorated by :meth:`contextlib.contextmanager`. It
can be called with ``with`` statement, and when exists from the
``with`` statement, the temporary path will be released.
Args:
filepath (str): Download a file from ``filepath``.
Examples:
>>> storage = HTTPStorage()
>>> # After existing from the ``with`` clause,
>>> # the path will be removed
>>> with storage.get_local_path('http://path/to/file') as path:
... # do something here
"""
try:
f = tempfile.NamedTemporaryFile(delete=False)
f.write(self.read(filepath))
f.close()
yield f.name
finally:
os.remove(f.name)
def write(self, obj: bytes, url: Union[str, Path]) -> None:
raise NotImplementedError("write is not supported by HTTP Storage")
def write_text(
self, obj: str, url: Union[str, Path], encoding: str = "utf-8"
) -> None:
raise NotImplementedError("write_text is not supported by HTTP Storage")
class OSSStorage(Storage):
"""OSS storage."""
def __init__(self, oss_config_file=None):
# read from config file or env var
raise NotImplementedError("OSSStorage.__init__ to be implemented in the future")
def read(self, filepath):
raise NotImplementedError("OSSStorage.read to be implemented in the future")
def read_text(self, filepath, encoding="utf-8"):
raise NotImplementedError(
"OSSStorage.read_text to be implemented in the future"
)
@contextlib.contextmanager
def as_local_path(self, filepath: str) -> Generator[Union[str, Path], None, None]:
"""Download a file from ``filepath``.
``as_local_path`` is decorated by :meth:`contextlib.contextmanager`. It
can be called with ``with`` statement, and when exists from the
``with`` statement, the temporary path will be released.
Args:
filepath (str): Download a file from ``filepath``.
Examples:
>>> storage = OSSStorage()
>>> # After existing from the ``with`` clause,
>>> # the path will be removed
>>> with storage.get_local_path('http://path/to/file') as path:
... # do something here
"""
try:
f = tempfile.NamedTemporaryFile(delete=False)
f.write(self.read(filepath))
f.close()
yield f.name
finally:
os.remove(f.name)
def write(self, obj: bytes, filepath: Union[str, Path]) -> None:
raise NotImplementedError("OSSStorage.write to be implemented in the future")
def write_text(
self, obj: str, filepath: Union[str, Path], encoding: str = "utf-8"
) -> None:
raise NotImplementedError(
"OSSStorage.write_text to be implemented in the future"
)
G_STORAGES = {}
class File(object):
_prefix_to_storage: dict = {
"oss": OSSStorage,
"http": HTTPStorage,
"https": HTTPStorage,
"local": LocalStorage,
}
@staticmethod
def _get_storage(uri):
assert isinstance(uri, str), f"uri should be str type, but got {type(uri)}"
if "://" not in uri:
# local path
storage_type = "local"
else:
prefix, _ = uri.split("://")
storage_type = prefix
assert storage_type in File._prefix_to_storage, (
f"Unsupported uri {uri}, valid prefixs: "
f"{list(File._prefix_to_storage.keys())}"
)
if storage_type not in G_STORAGES:
G_STORAGES[storage_type] = File._prefix_to_storage[storage_type]()
return G_STORAGES[storage_type]
@staticmethod
def read(uri: str) -> bytes:
"""Read data from a given ``filepath`` with 'rb' mode.
Args:
filepath (str or Path): Path to read data.
Returns:
bytes: Expected bytes object.
"""
storage = File._get_storage(uri)
return storage.read(uri)
@staticmethod
def read_text(uri: Union[str, Path], encoding: str = "utf-8") -> str:
"""Read data from a given ``filepath`` with 'r' mode.
Args:
filepath (str or Path): Path to read data.
encoding (str): The encoding format used to open the ``filepath``.
Default: 'utf-8'.
Returns:
str: Expected text reading from ``filepath``.
"""
storage = File._get_storage(uri)
return storage.read_text(uri)
@staticmethod
def write(obj: bytes, uri: Union[str, Path]) -> None:
"""Write data to a given ``filepath`` with 'wb' mode.
Note:
``write`` will create a directory if the directory of ``filepath``
does not exist.
Args:
obj (bytes): Data to be written.
filepath (str or Path): Path to write data.
"""
storage = File._get_storage(uri)
return storage.write(obj, uri)
@staticmethod
def write_text(obj: str, uri: str, encoding: str = "utf-8") -> None:
"""Write data to a given ``filepath`` with 'w' mode.
Note:
``write_text`` will create a directory if the directory of
``filepath`` does not exist.
Args:
obj (str): Data to be written.
filepath (str or Path): Path to write data.
encoding (str): The encoding format used to open the ``filepath``.
Default: 'utf-8'.
"""
storage = File._get_storage(uri)
return storage.write_text(obj, uri)
@contextlib.contextmanager
def as_local_path(uri: str) -> Generator[Union[str, Path], None, None]:
"""Only for unified API and do nothing."""
storage = File._get_storage(uri)
with storage.as_local_path(uri) as local_path:
yield local_path