# Copyright 2011-2014 Biomedical Imaging Group Rotterdam, Departments of
# Medical Informatics and Radiology, Erasmus MC, Rotterdam, The Netherlands
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
This module contains the FileSystem plugin for fastr
"""
import os
import shutil
import urllib.parse
import fastr
from fastr import exceptions
from fastr.core.ioplugin import IOPlugin
[docs]class FileSystem(IOPlugin):
"""
The FileSystem plugin is create to handle ``file://`` type or URLs. This is
generally not a good practice, as this is not portable over between
machines. However, for test purposes it might be useful.
The URL scheme is rather simple: ``file://host/path``
(see `wikipedia <http://en.wikipedia.org/wiki/File_URI_scheme>`_ for details)
We do not make use of the ``host`` part and at the moment only support
localhost (just leave the host empty) leading to ``file:///`` URLs.
.. warning:: This plugin ignores the hostname in the URL and does only
accept driver letters on Windows in the form ``c:/``
"""
scheme = 'file'
[docs] def __init__(self):
# initialize the instance and register the scheme
super(FileSystem, self).__init__()
[docs] def url_to_path(self, url):
""" Get the path to a file from a url.
Currently supports the file:// scheme
Examples:
.. code-block:: python
>>> 'file:///d:/data/project/file.ext'
'd:\\data\\project\\file.ext'
.. warning::
file:// will not function cross platform and is mainly for testing
"""
parsed_url = up.urlparse(str(url))
# Translate properly depending on the scheme being used
if parsed_url.scheme == self.scheme:
if os.name == 'nt':
path = parsed_url.path.lstrip('/')
else:
path = parsed_url.path
return self._correct_separators(path)
# return o.path
else:
raise exceptions.FastrValueError('This parses the {} scheme and not the {} scheme!'.format(self.scheme,
parsed_url.scheme))
[docs] def path_to_url(self, path, mountpoint=None):
""" Construct an url from a given mount point and a relative path to the mount point. """
return "{scheme}:///{path}".format(scheme=self.scheme, path=path)
[docs] def fetch_url(self, inurl, outpath):
"""
Fetch the files from the file.
:param inurl: url to the item in the data store, starts with ``file://``
:param outpath: path where to store the fetch data locally
"""
inpath = self.url_to_path(inurl)
# Clear away present data
if os.path.exists(outpath):
fastr.log.info('Removing currently exists data at {}'.format(outpath))
if os.path.islink(outpath):
os.remove(outpath)
elif os.path.isdir(outpath):
shutil.rmtree(outpath)
else:
os.remove(outpath)
try:
os.symlink(inpath, outpath)
fastr.log.debug('Symlink successful')
except OSError:
fastr.log.debug('Cannot symlink, fallback to copy')
if os.path.isdir(inpath):
shutil.copytree(inpath, outpath)
else:
shutil.copy2(inpath, outpath)
return outpath
[docs] def fetch_value(self, inurl):
"""
Fetch a value from an external file file.
:param inurl: url of the value to read
:return: the fetched value
"""
path = self.url_to_path(inurl)
with open(path, 'r') as file_handle:
data = file_handle.read()
return data
[docs] def put_url(self, inpath, outurl):
"""
Put the files to the external data store.
:param inpath: path of the local data
:param outurl: url to where to store the data, starts with ``file://``
"""
outpath = self.url_to_path(outurl)
fastr.vfs.copy_file_dir(inpath, outpath)
return os.path.exists(outpath)
[docs] def put_value(self, value, outurl):
"""
Put the value in the external data store.
:param value: value to store
:param outurl: url to where to store the data, starts with ``file://``
"""
outpath = self.url_to_path(outurl)
with open(outpath, 'w') as file_handle:
file_handle.write(str(value))
return os.path.exists(outpath)