266 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			266 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2018 New Vecotr Ltd
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| 
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| import contextlib
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| import logging
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| import os
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| import shutil
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| import sys
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| 
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| import six
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| 
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| from twisted.internet import defer
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| from twisted.protocols.basic import FileSender
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| 
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| from synapse.logging.context import defer_to_thread, make_deferred_yieldable
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| from synapse.util.file_consumer import BackgroundFileConsumer
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| 
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| from ._base import Responder
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| 
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| logger = logging.getLogger(__name__)
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| 
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| 
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| class MediaStorage(object):
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|     """Responsible for storing/fetching files from local sources.
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| 
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|     Args:
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|         hs (synapse.server.Homeserver)
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|         local_media_directory (str): Base path where we store media on disk
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|         filepaths (MediaFilePaths)
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|         storage_providers ([StorageProvider]): List of StorageProvider that are
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|             used to fetch and store files.
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|     """
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| 
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|     def __init__(self, hs, local_media_directory, filepaths, storage_providers):
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|         self.hs = hs
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|         self.local_media_directory = local_media_directory
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|         self.filepaths = filepaths
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|         self.storage_providers = storage_providers
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| 
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|     @defer.inlineCallbacks
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|     def store_file(self, source, file_info):
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|         """Write `source` to the on disk media store, and also any other
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|         configured storage providers
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| 
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|         Args:
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|             source: A file like object that should be written
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|             file_info (FileInfo): Info about the file to store
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| 
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|         Returns:
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|             Deferred[str]: the file path written to in the primary media store
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|         """
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| 
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|         with self.store_into_file(file_info) as (f, fname, finish_cb):
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|             # Write to the main repository
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|             yield defer_to_thread(
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|                 self.hs.get_reactor(), _write_file_synchronously, source, f
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|             )
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|             yield finish_cb()
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| 
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|         return fname
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| 
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|     @contextlib.contextmanager
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|     def store_into_file(self, file_info):
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|         """Context manager used to get a file like object to write into, as
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|         described by file_info.
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| 
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|         Actually yields a 3-tuple (file, fname, finish_cb), where file is a file
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|         like object that can be written to, fname is the absolute path of file
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|         on disk, and finish_cb is a function that returns a Deferred.
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| 
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|         fname can be used to read the contents from after upload, e.g. to
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|         generate thumbnails.
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| 
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|         finish_cb must be called and waited on after the file has been
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|         successfully been written to. Should not be called if there was an
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|         error.
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| 
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|         Args:
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|             file_info (FileInfo): Info about the file to store
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| 
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|         Example:
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| 
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|             with media_storage.store_into_file(info) as (f, fname, finish_cb):
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|                 # .. write into f ...
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|                 yield finish_cb()
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|         """
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| 
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|         path = self._file_info_to_path(file_info)
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|         fname = os.path.join(self.local_media_directory, path)
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| 
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|         dirname = os.path.dirname(fname)
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|         if not os.path.exists(dirname):
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|             os.makedirs(dirname)
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| 
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|         finished_called = [False]
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| 
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|         @defer.inlineCallbacks
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|         def finish():
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|             for provider in self.storage_providers:
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|                 yield provider.store_file(path, file_info)
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| 
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|             finished_called[0] = True
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| 
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|         try:
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|             with open(fname, "wb") as f:
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|                 yield f, fname, finish
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|         except Exception:
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|             t, v, tb = sys.exc_info()
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|             try:
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|                 os.remove(fname)
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|             except Exception:
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|                 pass
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|             six.reraise(t, v, tb)
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| 
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|         if not finished_called:
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|             raise Exception("Finished callback not called")
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| 
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|     @defer.inlineCallbacks
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|     def fetch_media(self, file_info):
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|         """Attempts to fetch media described by file_info from the local cache
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|         and configured storage providers.
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| 
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|         Args:
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|             file_info (FileInfo)
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| 
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|         Returns:
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|             Deferred[Responder|None]: Returns a Responder if the file was found,
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|                 otherwise None.
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|         """
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| 
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|         path = self._file_info_to_path(file_info)
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|         local_path = os.path.join(self.local_media_directory, path)
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|         if os.path.exists(local_path):
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|             return FileResponder(open(local_path, "rb"))
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| 
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|         for provider in self.storage_providers:
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|             res = yield provider.fetch(path, file_info)
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|             if res:
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|                 return res
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| 
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|         return None
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| 
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|     @defer.inlineCallbacks
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|     def ensure_media_is_in_local_cache(self, file_info):
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|         """Ensures that the given file is in the local cache. Attempts to
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|         download it from storage providers if it isn't.
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| 
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|         Args:
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|             file_info (FileInfo)
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| 
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|         Returns:
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|             Deferred[str]: Full path to local file
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|         """
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|         path = self._file_info_to_path(file_info)
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|         local_path = os.path.join(self.local_media_directory, path)
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|         if os.path.exists(local_path):
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|             return local_path
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| 
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|         dirname = os.path.dirname(local_path)
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|         if not os.path.exists(dirname):
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|             os.makedirs(dirname)
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| 
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|         for provider in self.storage_providers:
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|             res = yield provider.fetch(path, file_info)
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|             if res:
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|                 with res:
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|                     consumer = BackgroundFileConsumer(
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|                         open(local_path, "wb"), self.hs.get_reactor()
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|                     )
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|                     yield res.write_to_consumer(consumer)
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|                     yield consumer.wait()
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|                 return local_path
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| 
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|         raise Exception("file could not be found")
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| 
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|     def _file_info_to_path(self, file_info):
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|         """Converts file_info into a relative path.
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| 
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|         The path is suitable for storing files under a directory, e.g. used to
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|         store files on local FS under the base media repository directory.
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| 
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|         Args:
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|             file_info (FileInfo)
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| 
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|         Returns:
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|             str
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|         """
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|         if file_info.url_cache:
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|             if file_info.thumbnail:
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|                 return self.filepaths.url_cache_thumbnail_rel(
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|                     media_id=file_info.file_id,
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|                     width=file_info.thumbnail_width,
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|                     height=file_info.thumbnail_height,
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|                     content_type=file_info.thumbnail_type,
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|                     method=file_info.thumbnail_method,
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|                 )
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|             return self.filepaths.url_cache_filepath_rel(file_info.file_id)
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| 
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|         if file_info.server_name:
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|             if file_info.thumbnail:
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|                 return self.filepaths.remote_media_thumbnail_rel(
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|                     server_name=file_info.server_name,
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|                     file_id=file_info.file_id,
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|                     width=file_info.thumbnail_width,
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|                     height=file_info.thumbnail_height,
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|                     content_type=file_info.thumbnail_type,
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|                     method=file_info.thumbnail_method,
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|                 )
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|             return self.filepaths.remote_media_filepath_rel(
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|                 file_info.server_name, file_info.file_id
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|             )
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| 
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|         if file_info.thumbnail:
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|             return self.filepaths.local_media_thumbnail_rel(
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|                 media_id=file_info.file_id,
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|                 width=file_info.thumbnail_width,
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|                 height=file_info.thumbnail_height,
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|                 content_type=file_info.thumbnail_type,
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|                 method=file_info.thumbnail_method,
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|             )
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|         return self.filepaths.local_media_filepath_rel(file_info.file_id)
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| 
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| 
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| def _write_file_synchronously(source, dest):
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|     """Write `source` to the file like `dest` synchronously. Should be called
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|     from a thread.
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| 
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|     Args:
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|         source: A file like object that's to be written
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|         dest: A file like object to be written to
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|     """
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|     source.seek(0)  # Ensure we read from the start of the file
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|     shutil.copyfileobj(source, dest)
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| 
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| 
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| class FileResponder(Responder):
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|     """Wraps an open file that can be sent to a request.
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| 
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|     Args:
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|         open_file (file): A file like object to be streamed ot the client,
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|             is closed when finished streaming.
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|     """
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| 
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|     def __init__(self, open_file):
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|         self.open_file = open_file
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| 
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|     def write_to_consumer(self, consumer):
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|         return make_deferred_yieldable(
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|             FileSender().beginFileTransfer(self.open_file, consumer)
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|         )
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| 
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|     def __exit__(self, exc_type, exc_val, exc_tb):
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|         self.open_file.close()
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