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Diffstat (limited to 'mediagoblin/tools/workbench.py')
| -rw-r--r-- | mediagoblin/tools/workbench.py | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/mediagoblin/tools/workbench.py b/mediagoblin/tools/workbench.py new file mode 100644 index 00000000..0bd4096b --- /dev/null +++ b/mediagoblin/tools/workbench.py @@ -0,0 +1,164 @@ +# GNU MediaGoblin -- federated, autonomous media hosting +# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS. +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU Affero General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU Affero General Public License for more details. +# +# You should have received a copy of the GNU Affero General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +import os +import shutil +import tempfile + + +# Actual workbench stuff +# ---------------------- + +class Workbench(object): + """ + Represent the directory for the workbench + + WARNING: DO NOT create Workbench objects on your own, + let the WorkbenchManager do that for you! + """ + def __init__(self, dir): + """ + WARNING: DO NOT create Workbench objects on your own, + let the WorkbenchManager do that for you! + """ + self.dir = dir + + def __unicode__(self): + return unicode(self.dir) + + def __str__(self): + return str(self.dir) + + def __repr__(self): + try: + return str(self) + except AttributeError: + return 'None' + + def joinpath(self, *args): + return os.path.join(self.dir, *args) + + def localized_file(self, storage, filepath, + filename_if_copying=None, + keep_extension_if_copying=True): + """ + Possibly localize the file from this storage system (for read-only + purposes, modifications should be written to a new file.). + + If the file is already local, just return the absolute filename of that + local file. Otherwise, copy the file locally to the workbench, and + return the absolute path of the new file. + + If it is copying locally, we might want to require a filename like + "source.jpg" to ensure that we won't conflict with other filenames in + our workbench... if that's the case, make sure filename_if_copying is + set to something like 'source.jpg'. Relatedly, if you set + keep_extension_if_copying, you don't have to set an extension on + filename_if_copying yourself, it'll be set for you (assuming such an + extension can be extacted from the filename in the filepath). + + Returns: + localized_filename + + Examples: + >>> wb_manager.localized_file( + ... '/our/workbench/subdir', local_storage, + ... ['path', 'to', 'foobar.jpg']) + u'/local/storage/path/to/foobar.jpg' + + >>> wb_manager.localized_file( + ... '/our/workbench/subdir', remote_storage, + ... ['path', 'to', 'foobar.jpg']) + '/our/workbench/subdir/foobar.jpg' + + >>> wb_manager.localized_file( + ... '/our/workbench/subdir', remote_storage, + ... ['path', 'to', 'foobar.jpg'], 'source.jpeg', False) + '/our/workbench/subdir/foobar.jpeg' + + >>> wb_manager.localized_file( + ... '/our/workbench/subdir', remote_storage, + ... ['path', 'to', 'foobar.jpg'], 'source', True) + '/our/workbench/subdir/foobar.jpg' + """ + if storage.local_storage: + return storage.get_local_path(filepath) + else: + if filename_if_copying is None: + dest_filename = filepath[-1] + else: + orig_filename, orig_ext = os.path.splitext(filepath[-1]) + if keep_extension_if_copying and orig_ext: + dest_filename = filename_if_copying + orig_ext + else: + dest_filename = filename_if_copying + + full_dest_filename = os.path.join( + self.dir, dest_filename) + + # copy it over + storage.copy_locally( + filepath, full_dest_filename) + + return full_dest_filename + + def destroy(self): + """ + Destroy this workbench! Deletes the directory and all its contents! + + WARNING: Does no checks for a sane value in self.dir! + """ + # just in case + workbench = os.path.abspath(self.dir) + shutil.rmtree(workbench) + del self.dir + + def __enter__(self): + """Make Workbench a context manager so we can use `with Workbench() as bench:`""" + return self + + def __exit__(self, *args): + """Clean up context manager, aka ourselves, deleting the workbench""" + self.destroy() + + +class WorkbenchManager(object): + """ + A system for generating and destroying workbenches. + + Workbenches are actually just subdirectories of a (local) temporary + storage space for during the processing stage. The preferred way to + create them is to use: + + with workbenchmger.create() as workbench: + do stuff... + + This will automatically clean up all temporary directories even in + case of an exceptions. Also check the + @mediagoblin.decorators.get_workbench decorator for a convenient + wrapper. + """ + + def __init__(self, base_workbench_dir): + self.base_workbench_dir = os.path.abspath(base_workbench_dir) + if not os.path.exists(self.base_workbench_dir): + os.makedirs(self.base_workbench_dir) + + def create(self): + """ + Create and return the path to a new workbench (directory). + """ + return Workbench(tempfile.mkdtemp(dir=self.base_workbench_dir)) |