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from django.conf import settings
from django.core.urlresolvers import reverse
from djangorestframework.resource import Resource
from djangorestframework.response import Response
from djangorestframework import status
import pickle
import os
import uuid
import operator
OBJECT_STORE_DIR = os.path.join(settings.MEDIA_ROOT, 'objectstore')
MAX_FILES = 10
def remove_oldest_files(dir, max_files):
"""Remove the oldest files in a directory 'dir', leaving at most 'max_files' remaining.
We use this to limit the number of resources in the sandbox."""
filepaths = [os.path.join(dir, file) for file in os.listdir(dir) if not file.startswith('.')]
ctime_sorted_paths = [item[0] for item in sorted([(path, os.path.getctime(path)) for path in filepaths],
key=operator.itemgetter(1), reverse=True)]
[os.remove(path) for path in ctime_sorted_paths[max_files:]]
class ObjectStoreRoot(Resource):
"""Root of the Object Store API.
Allows the client to get a complete list of all the stored objects, or to create a new stored object."""
allowed_methods = anon_allowed_methods = ('GET', 'POST')
def get(self, request, auth):
"""Return a list of all the stored object URLs. (Ordered by creation time, newest first)"""
filepaths = [os.path.join(OBJECT_STORE_DIR, file) for file in os.listdir(OBJECT_STORE_DIR) if not file.startswith('.')]
ctime_sorted_basenames = [item[0] for item in sorted([(os.path.basename(path), os.path.getctime(path)) for path in filepaths],
key=operator.itemgetter(1), reverse=True)]
return [reverse('stored-object', kwargs={'key':key}) for key in ctime_sorted_basenames]
def post(self, request, auth, content):
"""Create a new stored object, with a unique key."""
key = str(uuid.uuid1())
pathname = os.path.join(OBJECT_STORE_DIR, key)
pickle.dump(content, open(pathname, 'wb'))
remove_oldest_files(OBJECT_STORE_DIR, MAX_FILES)
return Response(status.HTTP_201_CREATED, content, {'Location': reverse('stored-object', kwargs={'key':key})})
class StoredObject(Resource):
"""Represents a stored object.
The object may be any picklable content."""
allowed_methods = anon_allowed_methods = ('GET', 'PUT', 'DELETE')
def get(self, request, auth, key):
"""Return a stored object, by unpickling the contents of a locally stored file."""
pathname = os.path.join(OBJECT_STORE_DIR, key)
if not os.path.exists(pathname):
return Response(status.HTTP_404_NOT_FOUND)
return pickle.load(open(pathname, 'rb'))
def put(self, request, auth, content, key):
"""Update/create a stored object, by pickling the request content to a locally stored file."""
pathname = os.path.join(OBJECT_STORE_DIR, key)
pickle.dump(content, open(pathname, 'wb'))
return content
def delete(self, request, auth, key):
"""Delete a stored object, by removing it's pickled file."""
pathname = os.path.join(OBJECT_STORE_DIR, key)
if not os.path.exists(pathname):
return Response(status.HTTP_404_NOT_FOUND)
os.remove(pathname)
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