Vehicle-Anti-Theft-Face-Rec.../venv/Lib/site-packages/google/cloud/storage/_helpers.py

514 lines
19 KiB
Python

# Copyright 2014 Google LLC
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Helper functions for Cloud Storage utility classes.
These are *not* part of the API.
"""
import base64
from hashlib import md5
from datetime import datetime
import os
from six.moves.urllib.parse import urlsplit
from google.cloud.storage.constants import _DEFAULT_TIMEOUT
STORAGE_EMULATOR_ENV_VAR = "STORAGE_EMULATOR_HOST"
"""Environment variable defining host for Storage emulator."""
_DEFAULT_STORAGE_HOST = u"https://storage.googleapis.com"
# generation match parameters in camel and snake cases
_GENERATION_MATCH_PARAMETERS = (
("if_generation_match", "ifGenerationMatch"),
("if_generation_not_match", "ifGenerationNotMatch"),
("if_metageneration_match", "ifMetagenerationMatch"),
("if_metageneration_not_match", "ifMetagenerationNotMatch"),
("if_source_generation_match", "ifSourceGenerationMatch"),
("if_source_generation_not_match", "ifSourceGenerationNotMatch"),
("if_source_metageneration_match", "ifSourceMetagenerationMatch"),
("if_source_metageneration_not_match", "ifSourceMetagenerationNotMatch"),
)
def _get_storage_host():
return os.environ.get(STORAGE_EMULATOR_ENV_VAR, _DEFAULT_STORAGE_HOST)
def _validate_name(name):
"""Pre-flight ``Bucket`` name validation.
:type name: str or :data:`NoneType`
:param name: Proposed bucket name.
:rtype: str or :data:`NoneType`
:returns: ``name`` if valid.
"""
if name is None:
return
# The first and last characters must be alphanumeric.
if not all([name[0].isalnum(), name[-1].isalnum()]):
raise ValueError("Bucket names must start and end with a number or letter.")
return name
class _PropertyMixin(object):
"""Abstract mixin for cloud storage classes with associated properties.
Non-abstract subclasses should implement:
- path
- client
- user_project
:type name: str
:param name: The name of the object. Bucket names must start and end with a
number or letter.
"""
def __init__(self, name=None):
self.name = name
self._properties = {}
self._changes = set()
@property
def path(self):
"""Abstract getter for the object path."""
raise NotImplementedError
@property
def client(self):
"""Abstract getter for the object client."""
raise NotImplementedError
@property
def user_project(self):
"""Abstract getter for the object user_project."""
raise NotImplementedError
def _require_client(self, client):
"""Check client or verify over-ride.
:type client: :class:`~google.cloud.storage.client.Client` or
``NoneType``
:param client: the client to use. If not passed, falls back to the
``client`` stored on the current object.
:rtype: :class:`google.cloud.storage.client.Client`
:returns: The client passed in or the currently bound client.
"""
if client is None:
client = self.client
return client
def _encryption_headers(self):
"""Return any encryption headers needed to fetch the object.
.. note::
Defined here because :meth:`reload` calls it, but this method is
really only relevant for :class:`~google.cloud.storage.blob.Blob`.
:rtype: dict
:returns: a mapping of encryption-related headers.
"""
return {}
@property
def _query_params(self):
"""Default query parameters."""
params = {}
if self.user_project is not None:
params["userProject"] = self.user_project
return params
def reload(
self,
client=None,
projection="noAcl",
timeout=_DEFAULT_TIMEOUT,
if_generation_match=None,
if_generation_not_match=None,
if_metageneration_match=None,
if_metageneration_not_match=None,
):
"""Reload properties from Cloud Storage.
If :attr:`user_project` is set, bills the API request to that project.
:type client: :class:`~google.cloud.storage.client.Client` or
``NoneType``
:param client: the client to use. If not passed, falls back to the
``client`` stored on the current object.
:type projection: str
:param projection: (Optional) If used, must be 'full' or 'noAcl'.
Defaults to ``'noAcl'``. Specifies the set of
properties to return.
:type timeout: float or tuple
:param timeout: (Optional) The amount of time, in seconds, to wait
for the server response.
Can also be passed as a tuple (connect_timeout, read_timeout).
See :meth:`requests.Session.request` documentation for details.
:type if_generation_match: long
:param if_generation_match: (Optional) Make the operation conditional on whether
the blob's current generation matches the given value.
Setting to 0 makes the operation succeed only if there
are no live versions of the blob.
:type if_generation_not_match: long
:param if_generation_not_match: (Optional) Make the operation conditional on whether
the blob's current generation does not match the given
value. If no live blob exists, the precondition fails.
Setting to 0 makes the operation succeed only if there
is a live version of the blob.
:type if_metageneration_match: long
:param if_metageneration_match: (Optional) Make the operation conditional on whether the
blob's current metageneration matches the given value.
:type if_metageneration_not_match: long
:param if_metageneration_not_match: (Optional) Make the operation conditional on whether the
blob's current metageneration does not match the given value.
"""
client = self._require_client(client)
query_params = self._query_params
# Pass only '?projection=noAcl' here because 'acl' and related
# are handled via custom endpoints.
query_params["projection"] = projection
_add_generation_match_parameters(
query_params,
if_generation_match=if_generation_match,
if_generation_not_match=if_generation_not_match,
if_metageneration_match=if_metageneration_match,
if_metageneration_not_match=if_metageneration_not_match,
)
api_response = client._connection.api_request(
method="GET",
path=self.path,
query_params=query_params,
headers=self._encryption_headers(),
_target_object=self,
timeout=timeout,
)
self._set_properties(api_response)
def _patch_property(self, name, value):
"""Update field of this object's properties.
This method will only update the field provided and will not
touch the other fields.
It **will not** reload the properties from the server. The behavior is
local only and syncing occurs via :meth:`patch`.
:type name: str
:param name: The field name to update.
:type value: object
:param value: The value being updated.
"""
self._changes.add(name)
self._properties[name] = value
def _set_properties(self, value):
"""Set the properties for the current object.
:type value: dict or :class:`google.cloud.storage.batch._FutureDict`
:param value: The properties to be set.
"""
self._properties = value
# If the values are reset, the changes must as well.
self._changes = set()
def patch(
self,
client=None,
timeout=_DEFAULT_TIMEOUT,
if_generation_match=None,
if_generation_not_match=None,
if_metageneration_match=None,
if_metageneration_not_match=None,
):
"""Sends all changed properties in a PATCH request.
Updates the ``_properties`` with the response from the backend.
If :attr:`user_project` is set, bills the API request to that project.
:type client: :class:`~google.cloud.storage.client.Client` or
``NoneType``
:param client: the client to use. If not passed, falls back to the
``client`` stored on the current object.
:type timeout: float or tuple
:param timeout: (Optional) The amount of time, in seconds, to wait
for the server response.
Can also be passed as a tuple (connect_timeout, read_timeout).
See :meth:`requests.Session.request` documentation for details.
:type if_generation_match: long
:param if_generation_match: (Optional) Make the operation conditional on whether
the blob's current generation matches the given value.
Setting to 0 makes the operation succeed only if there
are no live versions of the blob.
:type if_generation_not_match: long
:param if_generation_not_match: (Optional) Make the operation conditional on whether
the blob's current generation does not match the given
value. If no live blob exists, the precondition fails.
Setting to 0 makes the operation succeed only if there
is a live version of the blob.
:type if_metageneration_match: long
:param if_metageneration_match: (Optional) Make the operation conditional on whether the
blob's current metageneration matches the given value.
:type if_metageneration_not_match: long
:param if_metageneration_not_match: (Optional) Make the operation conditional on whether the
blob's current metageneration does not match the given value.
"""
client = self._require_client(client)
query_params = self._query_params
# Pass '?projection=full' here because 'PATCH' documented not
# to work properly w/ 'noAcl'.
query_params["projection"] = "full"
_add_generation_match_parameters(
query_params,
if_generation_match=if_generation_match,
if_generation_not_match=if_generation_not_match,
if_metageneration_match=if_metageneration_match,
if_metageneration_not_match=if_metageneration_not_match,
)
update_properties = {key: self._properties[key] for key in self._changes}
# Make the API call.
api_response = client._connection.api_request(
method="PATCH",
path=self.path,
data=update_properties,
query_params=query_params,
_target_object=self,
timeout=timeout,
)
self._set_properties(api_response)
def update(
self,
client=None,
timeout=_DEFAULT_TIMEOUT,
if_generation_match=None,
if_generation_not_match=None,
if_metageneration_match=None,
if_metageneration_not_match=None,
):
"""Sends all properties in a PUT request.
Updates the ``_properties`` with the response from the backend.
If :attr:`user_project` is set, bills the API request to that project.
:type client: :class:`~google.cloud.storage.client.Client` or
``NoneType``
:param client: the client to use. If not passed, falls back to the
``client`` stored on the current object.
:type timeout: float or tuple
:param timeout: (Optional) The amount of time, in seconds, to wait
for the server response.
Can also be passed as a tuple (connect_timeout, read_timeout).
See :meth:`requests.Session.request` documentation for details.
:type if_generation_match: long
:param if_generation_match: (Optional) Make the operation conditional on whether
the blob's current generation matches the given value.
Setting to 0 makes the operation succeed only if there
are no live versions of the blob.
:type if_generation_not_match: long
:param if_generation_not_match: (Optional) Make the operation conditional on whether
the blob's current generation does not match the given
value. If no live blob exists, the precondition fails.
Setting to 0 makes the operation succeed only if there
is a live version of the blob.
:type if_metageneration_match: long
:param if_metageneration_match: (Optional) Make the operation conditional on whether the
blob's current metageneration matches the given value.
:type if_metageneration_not_match: long
:param if_metageneration_not_match: (Optional) Make the operation conditional on whether the
blob's current metageneration does not match the given value.
"""
client = self._require_client(client)
query_params = self._query_params
query_params["projection"] = "full"
_add_generation_match_parameters(
query_params,
if_generation_match=if_generation_match,
if_generation_not_match=if_generation_not_match,
if_metageneration_match=if_metageneration_match,
if_metageneration_not_match=if_metageneration_not_match,
)
api_response = client._connection.api_request(
method="PUT",
path=self.path,
data=self._properties,
query_params=query_params,
_target_object=self,
timeout=timeout,
)
self._set_properties(api_response)
def _scalar_property(fieldname):
"""Create a property descriptor around the :class:`_PropertyMixin` helpers.
"""
def _getter(self):
"""Scalar property getter."""
return self._properties.get(fieldname)
def _setter(self, value):
"""Scalar property setter."""
self._patch_property(fieldname, value)
return property(_getter, _setter)
def _write_buffer_to_hash(buffer_object, hash_obj, digest_block_size=8192):
"""Read blocks from a buffer and update a hash with them.
:type buffer_object: bytes buffer
:param buffer_object: Buffer containing bytes used to update a hash object.
:type hash_obj: object that implements update
:param hash_obj: A hash object (MD5 or CRC32-C).
:type digest_block_size: int
:param digest_block_size: The block size to write to the hash.
Defaults to 8192.
"""
block = buffer_object.read(digest_block_size)
while len(block) > 0:
hash_obj.update(block)
# Update the block for the next iteration.
block = buffer_object.read(digest_block_size)
def _base64_md5hash(buffer_object):
"""Get MD5 hash of bytes (as base64).
:type buffer_object: bytes buffer
:param buffer_object: Buffer containing bytes used to compute an MD5
hash (as base64).
:rtype: str
:returns: A base64 encoded digest of the MD5 hash.
"""
hash_obj = md5()
_write_buffer_to_hash(buffer_object, hash_obj)
digest_bytes = hash_obj.digest()
return base64.b64encode(digest_bytes)
def _convert_to_timestamp(value):
"""Convert non-none datetime to timestamp.
:type value: :class:`datetime.datetime`
:param value: The datetime to convert.
:rtype: int
:returns: The timestamp.
"""
utc_naive = value.replace(tzinfo=None) - value.utcoffset()
mtime = (utc_naive - datetime(1970, 1, 1)).total_seconds()
return mtime
def _add_generation_match_parameters(parameters, **match_parameters):
"""Add generation match parameters into the given parameters list.
:type parameters: list or dict
:param parameters: Parameters list or dict.
:type match_parameters: dict
:param match_parameters: if*generation*match parameters to add.
:raises: :exc:`ValueError` if ``parameters`` is not a ``list()``
or a ``dict()``.
"""
for snakecase_name, camelcase_name in _GENERATION_MATCH_PARAMETERS:
value = match_parameters.get(snakecase_name)
if value is not None:
if isinstance(parameters, list):
parameters.append((camelcase_name, value))
elif isinstance(parameters, dict):
parameters[camelcase_name] = value
else:
raise ValueError(
"`parameters` argument should be a dict() or a list()."
)
def _raise_if_more_than_one_set(**kwargs):
"""Raise ``ValueError`` exception if more than one parameter was set.
:type error: :exc:`ValueError`
:param error: Description of which fields were set
:raises: :class:`~ValueError` containing the fields that were set
"""
if sum(arg is not None for arg in kwargs.values()) > 1:
escaped_keys = ["'%s'" % name for name in kwargs.keys()]
keys_but_last = ", ".join(escaped_keys[:-1])
last_key = escaped_keys[-1]
msg = "Pass at most one of {keys_but_last} and {last_key}".format(
keys_but_last=keys_but_last, last_key=last_key
)
raise ValueError(msg)
def _bucket_bound_hostname_url(host, scheme=None):
"""Helper to build bucket bound hostname URL.
:type host: str
:param host: Host name.
:type scheme: str
:param scheme: (Optional) Web scheme. If passed, use it
as a scheme in the result URL.
:rtype: str
:returns: A bucket bound hostname URL.
"""
url_parts = urlsplit(host)
if url_parts.scheme and url_parts.netloc:
return host
return "{scheme}://{host}/".format(scheme=scheme, host=host)