CDN samples dir with snippet for signing urls

cdn/snippets.py

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+"""This application demonstrates how to perform operations on data (content)
+when using the 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 calendar
+import datetime
+import hashlib
+import hmac
+import time
+import urlparse
+import sys
+
+def sign_url(url, key_name, key, expiration_time):
+  """Gets the Signed URL string for the specified URL and configuration.
+
+  Args:
+    url: The URL to sign.
+    key_name: Signed URL key name to use for the 'KeyName=' query parameter.
+    key: The 16-byte unencoded secret key value to use for signing.
+    expiration_time: expiration time expressed as a UTC datetime object.
+
+  Returns:
+    Returns the Signed URL appended with the query parameters based on the
+    specified configuration.  Roughly of the form:
+    {url}{separator}Expires={expiration}&KeyName={key_name}&Signature={signature}
+
+  """
+  stripped_url = url.strip()
+  parsed_url = urlparse.urlsplit(stripped_url)
+  query_params = urlparse.parse_qs(parsed_url.query, keep_blank_values=True)
+  epoch = datetime.datetime.utcfromtimestamp(0)
+  expiration_timestamp = (expiration_time - epoch).total_seconds()
+
+  url_to_sign = '{url}{separator}Expires={expires}&KeyName={key_name}'.format(
+      url=stripped_url,
+      separator='&' if query_params else '?',
+      expires=expiration_timestamp,
+      key_name=key_name)
+
+  signature = base64.urlsafe_b64encode(
+      hmac.new(key, url_to_sign, hashlib.sha1).digest())
+
+  return '{url}&Signature={signature}'.format(
+      url=url_to_sign, signature=signature)
+
+
+if __name__ == '__main__':
+  parser = argparse.ArgumentParser(
+      description=__doc__,
+      formatter_class=argparse.RawDescriptionHelpFormatter)
+
+  subparsers = parser.add_subparsers(dest='command')
+  subparsers.add_parser('sign-url', help=sign_url.__doc__)
+
+  sign_url_parser = subparsers.add_parser('sign-url', help=sign_url.__doc__)
+  sign_url_parser.add_argument('url')
+  sign_url_parser.add_argument('key_name')
+  sign_url_parser.add_argument('key')
+  sign_url_parser.add_argument('expiration_time')
+
+  args = parser.parse_args()
+
+  args.url = "http://35.186.234.33/index.html"
+  args.key_name = "my-key"
+  args.key = base64.urlsafe_b64decode("nZtRohdNF9m3cKM24IcK4w==")
+  args.expiration_time = datetime.datetime.utcnow().replace(year=2020)
+
+  if args.command == 'sign-url':
+    print sign_url(args.url, args.key_name, args.key, args.expiration_time)
+