# 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 VirtualFileSystemValueList plugin for fastr
"""
import urlparse
import fastr
import fastr.exceptions as exceptions
from fastr.core.ioplugin import IOPlugin
class VirtualFileSystemValueList(IOPlugin):
"""
The VirtualFileSystemValueList an expand-only type of IOPlugin. No URLs
can actually be fetched, but it can expand a single URL into a larger
amount of URLs. A ``vfslist://`` URL basically is a url that points to a
file using vfs. This file then contains a number lines each containing
another URL.
If the contents of a file ``vfs://mount/some/path/contents`` would be::
vfs://mount/some/path/file1.txt
vfs://mount/some/path/file2.txt
vfs://mount/some/path/file3.txt
vfs://mount/some/path/file4.txt
Then using the URL ``vfslist://mount/some/path/contents`` as source data
would result in the four files being pulled.
.. note:: The URLs in a vfslist file do not have to use the ``vfs`` scheme,
but can use any scheme known to the Fastr system.
"""
scheme = 'vfslist'
[docs] def __init__(self):
super(VirtualFileSystemValueList, self).__init__()
[docs] def expand_url(self, url):
if fastr.data.url.get_url_scheme(url) != 'vfslist':
raise exceptions.FastrValueError('URL not of vfslist type!')
# Retrieve base path
parsed = urlparse.urlparse(url)
listurl = urlparse.urlunparse(urlparse.ParseResult(scheme='vfs', netloc=parsed.netloc, path=parsed.path, params='', query='', fragment=''))
listpath = fastr.ioplugins.url_to_path(listurl)
with open(listpath, 'r') as file_handle:
data = file_handle.read()
valuelist = tuple((None, x.strip()) for x in data.strip().split('\n'))
return valuelist