fix(storage): proper link generate with 𝘨𝘦𝘵_𝘶𝘳𝘭

1️⃣  𝘵𝘰𝘬𝘦𝘯 param is now optional.
2️⃣  𝘦𝘹𝘱𝘪𝘳𝘢𝘵𝘪𝘰𝘯_𝘩𝘰𝘶𝘳, an optional param added which works only for link generated with admin credentials.
3️⃣  resolves proper link generation with the use of 𝘵𝘰𝘬𝘦𝘯 param.
4️⃣  resolves link generation of any user protected file, instead of links for public to anyone contents.

Co-Authored-By: Daniel Marconi <45787099+kinguardo@users.noreply.github.com>
Co-Authored-By: Khin Eaindray Htun <91376371+hereisamara@users.noreply.github.com>

Author: 3 people

firebase/storage/__init__.py

@@ -12,6 +12,7 @@
 	https://firebase.google.com/docs/reference/rest/storage/rest
 """
 
+import datetime
 import requests
 from gcloud import storage
 from urllib.parse import quote
@@ -224,26 +225,46 @@ def download(self, filename, token=None):
 					for chunk in r:
 						f.write(chunk)
 
-	def get_url(self, token):
+	def get_url(self, token=None, expiration_hour=24):
 		""" Fetches URL for file.
 
 
 		:type token: str
-		:param token: Firebase Auth User ID Token.
+		:param token: (Optional) Firebase Auth User ID Token, defaults
+			to :data:`None`.
 
+		:type expiration_hour: int
+		:param expiration_hour: (Optional) time in ``hour`` for URL to
+			expire after, defaults to 24 hours. Works only for links
+			generated with admin credentials.
 
 		:return: URL for the file.
 		:rtype: str
 		"""
 
+		# reset path
 		path = self.path
 		self.path = None
 
+		# remove leading backlash
 		if path.startswith('/'):
 			path = path[1:]
 
-		if token:
-			return "{0}/o/{1}?alt=media&token={2}".format(self.storage_bucket, quote(path, safe=''), token)
+		if self.credentials:
+			blob = self.bucket.get_blob(path)
+			if blob:
+				return blob.generate_signed_url(datetime.timedelta(hours=expiration_hour), method='GET')
+
+		elif token:
+
+			# retrieve download tokens first
+			headers = {"Authorization": "Bearer " + token}
+			request_ref = "{0}/o/{1}".format(self.storage_bucket, quote(path, safe=''))
+			request_object = self.requests.get(request_ref, headers=headers)
+
+			raise_detailed_error(request_object)
+
+			return "{0}/o/{1}?alt=media&token={2}".format(self.storage_bucket, quote(path, safe=''), request_object.json()['downloadTokens'])
 
 		return "{0}/o/{1}?alt=media".format(self.storage_bucket, quote(path, safe=''))