# Copyright 2015 Google 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

#

# 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.

from __future__ import absolute_import

import datetime

from flask import current_app

from gcloud import storage

import six

from werkzeug import secure_filename

from werkzeug.exceptions import BadRequest

def _get_storage_client():

return storage.Client(

project=current_app.config['PROJECT_ID'])

def _check_extension(filename, allowed_extensions):

if ('.' not in filename or

filename.split('.').pop().lower() not in allowed_extensions):

raise BadRequest(

"{0} has an invalid name or extension".format(filename))

def _safe_filename(filename):

"""

Generates a safe filename that is unlikely to collide with existing objects

in Google Cloud Storage.

``filename.ext`` is transformed into ``filename-YYYY-MM-DD-HHMMSS.ext``

"""

filename = secure_filename(filename)

date = datetime.datetime.utcnow().strftime("%Y-%m-%d-%H%M%S")

basename, extension = filename.rsplit('.', 1)

return "{0}-{1}.{2}".format(basename, date, extension)

def upload_file(file_stream, filename, content_type):

"""

Uploads a file to a given Cloud Storage bucket and returns the public url

to the new object.

"""

_check_extension(filename, current_app.config['ALLOWED_EXTENSIONS'])

filename = _safe_filename(filename)

client = _get_storage_client()

bucket = client.get_bucket(current_app.config['CLOUD_STORAGE_BUCKET'])

blob = bucket.blob(filename)

blob.upload_from_string(

file_stream,

content_type=content_type)

url = blob.public_url

if isinstance(url, six.binary_type):

url = url.decode('utf-8')

return url