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from django.conf import settings
from djangorestframework.reverse import reverse
from djangorestframework.views import View
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
if not os.path.exists(OBJECT_STORE_DIR):
os.makedirs(OBJECT_STORE_DIR)
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:]]
def get_filename(key):
"""
Given a stored object's key returns the file's path.
"""
return os.path.join(OBJECT_STORE_DIR, key)
def get_file_url(key, request):
"""
Given a stored object's key returns the URL for the object.
"""
return reverse('stored-object', kwargs={'key': key}, request=request)
class ObjectStoreRoot(View):
"""
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.
"""
def get(self, request):
"""
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)]
content = [get_file_url(key, request)
for key in ctime_sorted_basenames]
return Response(content)
def post(self, request):
"""
Create a new stored object, with a unique key.
"""
key = str(uuid.uuid1())
filename = get_filename(key)
pickle.dump(self.CONTENT, open(filename, 'wb'))
remove_oldest_files(OBJECT_STORE_DIR, MAX_FILES)
url = get_file_url(key, request)
return Response(self.CONTENT, status.HTTP_201_CREATED, {'Location': url})
class StoredObject(View):
"""
Represents a stored object.
The object may be any picklable content.
"""
def get(self, request, key):
"""
Return a stored object, by unpickling the contents of a locally
stored file.
"""
filename = get_filename(key)
if not os.path.exists(filename):
return Response(status=status.HTTP_404_NOT_FOUND)
return Response(pickle.load(open(filename, 'rb')))
def put(self, request, key):
"""
Update/create a stored object, by pickling the request content to a
locally stored file.
"""
filename = get_filename(key)
pickle.dump(self.CONTENT, open(filename, 'wb'))
return Response(self.CONTENT)
def delete(self, request, key):
"""
Delete a stored object, by removing it's pickled file.
"""
filename = get_filename(key)
if not os.path.exists(filename):
return Response(status=status.HTTP_404_NOT_FOUND)
os.remove(filename)
return Response()
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