Source code for girder.utility.abstract_assetstore_adapter

#  Copyright 2013 Kitware Inc.
#  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
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  See the License for the specific language governing permissions and
#  limitations under the License.

import itertools
import os
import re
import six

from import setResponseHeader, setContentDisposition
from girder.constants import SettingKey
from girder.models.model_base import GirderException, ValidationException
from girder.models.setting import Setting
from girder.utility import progress, RequestBodyStream
from .model_importer import ModelImporter

[docs]class FileHandle(object): """ This is the base class that is returned for the file-like API into Girder file objects. The ``open`` method of assetstore implementations is responsible for returning an instance of this class or one of its subclasses. This base class implementation is returned by the abstract assetstore adapter, and does not leverage any details of the assetstore implementations. These file handles are stateful, and therefore not safe for concurrent access. If used by multiple threads, mutexes should be used. :param file: The file object to which this file-like object corresponds. :type file: dict :param adapter: The assetstore adapter corresponding to this file. :type adapter: girder.utility.abstract_assetstore_adapter.AbstractAssetstoreAdapter """ def __init__(self, file, adapter): self._file = file self._adapter = adapter self._pos = None # If a read is requested that is longer than the specified size, raise # an exception. This prevents unbounded memory use. self._maximumReadSize = 16 * 1024 * 1024 def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): self.close()
[docs] def read(self, size=None): """ Read *size* bytes from the file data. :param size: The number of bytes to read from the current position. The actual number returned could be less than this if the end of the file is reached. An empty response indicates that the file has been completely consumed. If None or negative, read to the end of the file. :type size: int :rtype: bytes """ if size is None or size < 0: size = self._file['size'] - self._pos if size > self._maximumReadSize: raise GirderException('Read exceeds maximum allowed size.') data = six.BytesIO() length = 0 for chunk in itertools.chain(self._prev, self._stream): chunkLen = len(chunk) if chunkLen == 0: break if length + chunkLen <= size: data.write(chunk) self._prev = [] length += chunkLen if length == size: break else: chunkLen = min(size - length, chunkLen) data.write(chunk[:chunkLen]) self._prev = [chunk[chunkLen:]] length += chunkLen break self._pos += length return data.getvalue()
def tell(self): return self._pos def seek(self, offset, whence=os.SEEK_SET): oldPos = self._pos if whence == os.SEEK_SET: self._pos = offset elif whence == os.SEEK_CUR: self._pos += offset elif whence == os.SEEK_END: self._pos = max(self._file['size'] + offset, 0) if self._pos != oldPos: self._prev = [] self._stream = self._adapter.downloadFile(self._file, offset=self._pos, headers=False)() def close(self): pass
[docs]class AbstractAssetstoreAdapter(ModelImporter): """ This defines the interface to be used by all assetstore adapters. """ def __init__(self, assetstore): self.assetstore = assetstore @staticmethod
[docs] def validateInfo(doc): """ Adapters may implement this if they need to perform any validation steps whenever the assetstore info is saved to the database. It should return the document with any necessary alterations in the success case, or throw an exception if validation fails. """ return doc
[docs] def fileIndexFields(): """ Default behavior is that no additional file fields need to be indexed within the database. """ return []
[docs] def capacityInfo(self): """ Assetstore types that are able to report how much free and/or total capacity they have should override this method. Default behavior is to report both quantities as unknown. :returns: A dict with 'free' and 'total' keys whose values are either bytes (ints) or None for an unknown quantity. """ return { 'free': None, 'total': None }
[docs] def initUpload(self, upload): """ This must be called before any chunks are uploaded to do any additional behavior and optionally augment the upload document. The method must return the upload document. Default behavior is to simply return the upload document unmodified. :param upload: The upload document to optionally augment. :type upload: dict """ return upload # pragma: no cover
[docs] def uploadChunk(self, upload, chunk): """ Call this method to process each chunk of an upload. :param upload: The upload document to update. :type upload: dict :param chunk: The file object representing the chunk that was uploaded. :type chunk: file :returns: Must return the upload document with any optional changes. """ raise NotImplementedError('Must override processChunk in %s.' % self.__class__.__name__) # pragma: no cover
[docs] def finalizeUpload(self, upload, file): """ Call this once the last chunk has been processed. This method does not need to delete the upload document as that will be deleted by the caller afterward. This method may augment the File document, and must return the File document. :param upload: The upload document. :type upload: dict :param file: The file document that was created. :type file: dict :returns: The file document with optional modifications. """ return file
[docs] def requestOffset(self, upload): """ Request the offset for resuming an interrupted upload. Default behavior simply returns the 'received' field of the upload document. This method exists because in some cases, such as when the server crashes, it's possible that the received field is not accurate, so adapters may implement this to provide the actual next byte required. """ return upload['received']
[docs] def deleteFile(self, file): """ This is called when a File is deleted to allow the adapter to remove the data from within the assetstore. This method should not modify or delete the file object, as the caller will delete it afterward. :param file: The File document about to be deleted. :type file: dict """ raise NotImplementedError('Must override deleteFile in %s.' % self.__class__.__name__) # pragma: no cover
[docs] def shouldImportFile(self, path, params): """ This is a helper used during the import process to determine if a file located at the specified path should be imported, based on the request parameters. Exclusion takes precedence over inclusion. :param path: The path of the file. :type path: str :param params: The request parameters. :type params: dict :rtype: bool """ include = params.get('fileIncludeRegex') exclude = params.get('fileExcludeRegex') fname = os.path.basename(path) if exclude and re.match(exclude, fname): return False if include: return re.match(include, fname) return True
[docs] def downloadFile(self, file, offset=0, headers=True, endByte=None, contentDisposition=None, extraParameters=None, **kwargs): """ This method is in charge of returning a value to the RESTful endpoint that can be used to download the file. This should either return a generator function that yields the bytes of the file (which will stream the file directly), or modify the response headers and raise a `cherrypy.HTTPRedirect`. :param file: The file document being downloaded. :type file: dict :param offset: Offset in bytes to start the download at. :type offset: int :param headers: Flag for whether headers should be sent on the response. :type headers: bool :param endByte: Final byte to download. If ``None``, downloads to the end of the file. :type endByte: int or None :param contentDisposition: Value for Content-Disposition response header disposition-type value. :type contentDisposition: str or None :type extraParameters: str or None """ raise NotImplementedError('Must override downloadFile in %s.' % self.__class__.__name__) # pragma: no cover
[docs] def findInvalidFiles(self, progress=progress.noProgress, filters=None, checkSize=True, **kwargs): """ Finds and yields any invalid files in the assetstore. It is left to the caller to decide what to do with them. :param progress: Pass a progress context to record progress. :type progress: :py:class:`girder.utility.progress.ProgressContext` :param filters: Additional query dictionary to restrict the search for files. There is no need to set the ``assetstoreId`` in the filters, since that is done automatically. :type filters: dict or None :param checkSize: Whether to make sure the size of the underlying data matches the size of the file. :type checkSize: bool """ raise NotImplementedError('Must override findInvalidFiles in %s.' % self.__class__.__name__) # pragma: no cover
[docs] def copyFile(self, srcFile, destFile): """ This method copies the necessary fields and data so that the destination file contains the same data as the source file. :param srcFile: The original File document. :type srcFile: dict :param destFile: The File which should have the data copied to it. :type destFile: dict :returns: A dict with the destination file. """ return destFile
[docs] def getChunkSize(self, chunk): """ Given a chunk that is either a file-like object or a string, attempt to determine its length. If it is a file-like object, then this relies on being able to use fstat. :param chunk: the chunk to get the size of :type chunk: a file-like object or a string :returns: the length of the chunk if known, or None. """ if isinstance(chunk, (six.BytesIO, RequestBodyStream)): return elif hasattr(chunk, "fileno"): return os.fstat(chunk.fileno()).st_size elif isinstance(chunk, six.text_type): return len(chunk.encode('utf8')) else: return len(chunk)
[docs] def setContentHeaders(self, file, offset, endByte, contentDisposition=None): """ Sets the Content-Length, Content-Disposition, Content-Type, and also the Content-Range header if this is a partial download. :param file: The file being downloaded. :param offset: The start byte of the download. :type offset: int :param endByte: The end byte of the download (non-inclusive). :type endByte: int :param contentDisposition: Content-Disposition response header disposition-type value, if None, Content-Disposition will be set to 'attachment; filename=$filename'. :type contentDisposition: str or None """ setResponseHeader( 'Content-Type', file.get('mimeType') or 'application/octet-stream') setContentDisposition(file['name'], contentDisposition or 'attachment') setResponseHeader('Content-Length', max(endByte - offset, 0)) if (offset or endByte < file['size']) and file['size']: setResponseHeader( 'Content-Range', 'bytes %d-%d/%d' % (offset, endByte - 1, file['size']))
[docs] def checkUploadSize(self, upload, chunkSize): """ Check if the upload is valid based on the chunk size. If this raises an exception, then the caller should clean up and reraise the exception. :param upload: the dictionary of upload information. The received and size values are used. :param chunkSize: the chunk size that needs to be validated. :type chunkSize: a non-negative integer or None if unknown. """ if 'received' not in upload or 'size' not in upload: return if chunkSize is None: return if upload['received'] + chunkSize > upload['size']: raise ValidationException('Received too many bytes.') if (upload['received'] + chunkSize != upload['size'] and chunkSize < Setting().get(SettingKey.UPLOAD_MINIMUM_CHUNK_SIZE)): raise ValidationException('Chunk is smaller than the minimum size.')
[docs] def cancelUpload(self, upload): """ This is called when an upload has been begun and it should be abandoned. It must clean up temporary files, chunks, or whatever other information the assetstore contains. """ raise NotImplementedError('Must override cancelUpload in %s.' % self.__class__.__name__) # pragma: no cover
[docs] def untrackedUploads(self, knownUploads=(), delete=False): """ List and optionally discard uploads that are in the assetstore but not in the known list. :param knownUploads: a list of upload dictionaries of all known incomplete uploads. :type knownUploads: list :param delete: if True, delete any unknown uploads. :type delete: bool :returns: a list of unknown uploads. """ return ()
[docs] def importData(self, parent, parentType, params, progress, user, **kwargs): """ Assetstores that are capable of importing pre-existing data from the underlying storage medium can implement this method. :param parent: The parent object to import into. :param parentType: The model type of the parent object (folder, user, or collection). :type parentType: str :param params: Additional parameters required for the import process. Typically includes an importPath field representing a root path on the underlying storage medium. :type params: dict :param progress: Object on which to record progress if possible. :type progress: :py:class:`girder.utility.progress.ProgressContext` :param user: The Girder user performing the import. :type user: dict or None """ raise NotImplementedError( 'The %s assetstore type does not support importing existing data.' % self.__class__.__name__) # pragma: no cover
[docs] def fileUpdated(self, file): """ This is called when the file document has been changed. Any assetstore implementation that needs to do anything when the file document changes should override this method. :param file: The updated file document. :type file: dict """ pass
[docs] def open(self, file): """ Exposes a Girder file as a python file-like object. At the moment, this is a read-only interface, the equivalent of opening a system file with 'rb' mode. :param file: A Girder file document. :type file: dict :return: A file-like object containing the bytes of the file. :rtype: FileHandle """ return FileHandle(file, self)