CDN samples dir with snippet for signing urls (#1383)

cdn/README.rst

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+.. This file is automatically generated. Do not edit this file directly.
+
+Google Cloud CDN Python Samples
+===============================================================================
+
+.. image:: https://gstatic.com/cloudssh/images/open-btn.png
+   :target: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=cdn/README.rst
+
+
+This directory contains samples for Google Cloud CDN. 'Google Cloud CDN'_ enables low-latency, low-cost content delivery using Google's global network
+
+
+
+
+.. _Google Cloud CDN: https://cloud.google.com/cdn/docs
+
+
+Samples
+-------------------------------------------------------------------------------
+
+Snippets
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+.. image:: https://gstatic.com/cloudssh/images/open-btn.png
+   :target: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=cdn/snippets.py;cdn/README.rst
+
+
+
+
+To run this sample:
+
+.. code-block:: bash
+
+    $ python snippets.py
+
+    usage: snippets.py [-h] {sign-url} ...
+
+    This application demonstrates how to perform operations on data (content)
+    when using Google Cloud CDN (Content Delivery Network).
+
+    For more information, see the README.md under /cdn and the documentation
+    at https://cloud.google.com/cdn/docs.
+
+    positional arguments:
+      {sign-url}
+        sign-url  Sign a URL to grant temporary authorized access.
+
+    optional arguments:
+      -h, --help  show this help message and exit
+
+
+
+
+
+.. _Google Cloud SDK: https://cloud.google.com/sdk/

cdn/README.rst.in

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+# Used to generate README.rst
+
+product:
+  name: Google Cloud CDN
+  short_name: Cloud CDN
+  url: https://cloud.google.com/cdn/docs
+  description: >
+    'Google Cloud CDN'_ enables low-latency, low-cost content delivery using
+    Google's global network
+
+samples:
+  - name: Snippets
+    file: snippets.py
+    show_help: true
+
+folder: cdn

cdn/requirements.txt

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+six

cdn/snippets.py

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+#!/usr/bin/env python
+#
+# Copyright 2017 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.
+
+"""This application demonstrates how to perform operations on data (content)
+when using Google Cloud CDN (Content Delivery Network).
+
+For more information, see the README.md under /cdn and the documentation
+at https://cloud.google.com/cdn/docs.
+"""
+
+import argparse
+import base64
+import datetime
+import hashlib
+import hmac
+
+from six.moves import urllib
+
+
+# [BEGIN sign_url]
+def sign_url(url, key_name, base64_key, expiration_time):
+    """Gets the Signed URL string for the specified URL and configuration.
+
+    Args:
+        url: URL to sign as a string.
+        key_name: name of the signing key as a string.
+        base64_key: signing key as a base64 encoded string.
+        expiration_time: expiration time as a UTC datetime object.
+
+    Returns:
+        Returns the Signed URL appended with the query parameters based on the
+        specified configuration.
+    """
+    stripped_url = url.strip()
+    parsed_url = urllib.parse.urlsplit(stripped_url)
+    query_params = urllib.parse.parse_qs(
+        parsed_url.query, keep_blank_values=True)
+    epoch = datetime.datetime.utcfromtimestamp(0)
+    expiration_timestamp = int((expiration_time - epoch).total_seconds())
+    decoded_key = base64.urlsafe_b64decode(base64_key)
+
+    url_pattern = u'{url}{separator}Expires={expires}&KeyName={key_name}'
+
+    url_to_sign = url_pattern.format(
+            url=stripped_url,
+            separator='&' if query_params else '?',
+            expires=expiration_timestamp,
+            key_name=key_name)
+
+    digest = hmac.new(
+        decoded_key, url_to_sign.encode('utf-8'), hashlib.sha1).digest()
+    signature = base64.urlsafe_b64encode(digest).decode('utf-8')
+
+    signed_url = u'{url}&Signature={signature}'.format(
+            url=url_to_sign, signature=signature)
+
+    print(signed_url)
+# [END sign_url]
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+            description=__doc__,
+            formatter_class=argparse.RawDescriptionHelpFormatter)
+
+    subparsers = parser.add_subparsers(dest='command')
+
+    sign_url_parser = subparsers.add_parser(
+            'sign-url',
+            help="Sign a URL to grant temporary authorized access.")
+    sign_url_parser.add_argument(
+            'url', help='The URL to sign.')
+    sign_url_parser.add_argument(
+            'key_name',
+            help='Key name for the signing key.')
+    sign_url_parser.add_argument(
+            'base64_key',
+            help='The base64 encoded signing key.')
+    sign_url_parser.add_argument(
+            'expiration_time',
+            type=lambda d: datetime.datetime.utcfromtimestamp(float(d)),
+            help='Expiration time expessed as seconds since the epoch.')
+
+    args = parser.parse_args()
+
+    if args.command == 'sign-url':
+        sign_url(
+            args.url, args.key_name, args.base64_key, args.expiration_time)

cdn/snippets_test.py

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+#!/usr/bin/env python
+#
+# Copyright 2017 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.
+
+"""Tests for snippets."""
+
+import datetime
+
+import snippets
+
+
+def test_sign_url(capsys):
+    snippets.sign_url(
+        'http://35.186.234.33/index.html',
+        'my-key',
+        'nZtRohdNF9m3cKM24IcK4w==',
+        datetime.datetime.utcfromtimestamp(1549751401))
+    snippets.sign_url(
+        'http://www.example.com/',
+        'my-key',
+        'nZtRohdNF9m3cKM24IcK4w==',
+        datetime.datetime.utcfromtimestamp(1549751401))
+    snippets.sign_url(
+        'http://www.example.com/some/path?some=query&another=param',
+        'my-key',
+        'nZtRohdNF9m3cKM24IcK4w==',
+        datetime.datetime.utcfromtimestamp(1549751401))
+
+    out, _ = capsys.readouterr()
+
+    results = out.splitlines()
+    assert results[0] == (
+        'http://35.186.234.33/index.html?Expires=1549751401&KeyName=my-key&'
+        'Signature=CRFqQnVfFyiUyR63OQf-HRUpIwc=')
+    assert results[1] == (
+        'http://www.example.com/?Expires=1549751401&KeyName=my-key&'
+        'Signature=OqDUFfHpN5Vxga6r80bhsgxKves=')
+    assert results[2] == (
+        'http://www.example.com/some/path?some=query&another=param&Expires='
+        '1549751401&KeyName=my-key&Signature=9Q9TCxSju8-W5nUkk5CuTrun2_o=')