chore: Dropped the dependency on six (#385)

* Removing Python 2 support

* Upgraded to Pylint 2.x and fixed all linter errors for Python 3

* Removed the dependency on the six library

Author: hiranya911

firebase_admin/__init__.py

@@ -18,8 +18,6 @@
 import os
 import threading
 
-import six
-
 from firebase_admin import credentials
 from firebase_admin.__about__ import __version__
 
@@ -126,7 +124,7 @@ def get_app(name=_DEFAULT_APP_NAME):
       ValueError: If the specified name is not a string, or if the specified
           app does not exist.
     """
-    if not isinstance(name, six.string_types):
+    if not isinstance(name, str):
         raise ValueError('Illegal app name argument type: "{}". App name '
                          'must be a string.'.format(type(name)))
     with _apps_lock:
@@ -203,7 +201,7 @@ def __init__(self, name, credential, options):
         Raises:
           ValueError: If an argument is None or invalid.
         """
-        if not name or not isinstance(name, six.string_types):
+        if not name or not isinstance(name, str):
             raise ValueError('Illegal Firebase app name "{0}" provided. App name must be a '
                              'non-empty string.'.format(name))
         self._name = name
@@ -221,7 +219,7 @@ def __init__(self, name, credential, options):
 
     @classmethod
     def _validate_project_id(cls, project_id):
-        if project_id is not None and not isinstance(project_id, six.string_types):
+        if project_id is not None and not isinstance(project_id, str):
             raise ValueError(
                 'Invalid project ID: "{0}". project ID must be a string.'.format(project_id))
 
@@ -286,7 +284,7 @@ def _get_service(self, name, initializer):
         Raises:
           ValueError: If the provided name is invalid, or if the App is already deleted.
         """
-        if not name or not isinstance(name, six.string_types):
+        if not name or not isinstance(name, str):
             raise ValueError(
                 'Illegal name argument: "{0}". Name must be a non-empty string.'.format(name))
         with self._lock:

firebase_admin/_auth_utils.py

@@ -16,9 +16,7 @@
 
 import json
 import re
-
-import six
-from six.moves import urllib
+from urllib import parse
 
 from firebase_admin import exceptions
 from firebase_admin import _utils
@@ -35,7 +33,7 @@
 def validate_uid(uid, required=False):
     if uid is None and not required:
         return None
-    if not isinstance(uid, six.string_types) or not uid or len(uid) > 128:
+    if not isinstance(uid, str) or not uid or len(uid) > 128:
         raise ValueError(
             'Invalid uid: "{0}". The uid must be a non-empty string with no more than 128 '
             'characters.'.format(uid))
@@ -44,7 +42,7 @@ def validate_uid(uid, required=False):
 def validate_email(email, required=False):
     if email is None and not required:
         return None
-    if not isinstance(email, six.string_types) or not email:
+    if not isinstance(email, str) or not email:
         raise ValueError(
             'Invalid email: "{0}". Email must be a non-empty string.'.format(email))
     parts = email.split('@')
@@ -61,7 +59,7 @@ def validate_phone(phone, required=False):
     """
     if phone is None and not required:
         return None
-    if not isinstance(phone, six.string_types) or not phone:
+    if not isinstance(phone, str) or not phone:
         raise ValueError('Invalid phone number: "{0}". Phone number must be a non-empty '
                          'string.'.format(phone))
     if not phone.startswith('+') or not re.search('[a-zA-Z0-9]', phone):
@@ -72,22 +70,22 @@ def validate_phone(phone, required=False):
 def validate_password(password, required=False):
     if password is None and not required:
         return None
-    if not isinstance(password, six.string_types) or len(password) < 6:
+    if not isinstance(password, str) or len(password) < 6:
         raise ValueError(
             'Invalid password string. Password must be a string at least 6 characters long.')
     return password
 
 def validate_bytes(value, label, required=False):
     if value is None and not required:
         return None
-    if not isinstance(value, six.binary_type) or not value:
+    if not isinstance(value, bytes) or not value:
         raise ValueError('{0} must be a non-empty byte sequence.'.format(label))
     return value
 
 def validate_display_name(display_name, required=False):
     if display_name is None and not required:
         return None
-    if not isinstance(display_name, six.string_types) or not display_name:
+    if not isinstance(display_name, str) or not display_name:
         raise ValueError(
             'Invalid display name: "{0}". Display name must be a non-empty '
             'string.'.format(display_name))
@@ -96,7 +94,7 @@ def validate_display_name(display_name, required=False):
 def validate_provider_id(provider_id, required=True):
     if provider_id is None and not required:
         return None
-    if not isinstance(provider_id, six.string_types) or not provider_id:
+    if not isinstance(provider_id, str) or not provider_id:
         raise ValueError(
             'Invalid provider ID: "{0}". Provider ID must be a non-empty '
             'string.'.format(provider_id))
@@ -106,12 +104,12 @@ def validate_photo_url(photo_url, required=False):
     """Parses and validates the given URL string."""
     if photo_url is None and not required:
         return None
-    if not isinstance(photo_url, six.string_types) or not photo_url:
+    if not isinstance(photo_url, str) or not photo_url:
         raise ValueError(
             'Invalid photo URL: "{0}". Photo URL must be a non-empty '
             'string.'.format(photo_url))
     try:
-        parsed = urllib.parse.urlparse(photo_url)
+        parsed = parse.urlparse(photo_url)
         if not parsed.netloc:
             raise ValueError('Malformed photo URL: "{0}".'.format(photo_url))
         return photo_url

firebase_admin/_messaging_encoder.py

@@ -20,8 +20,6 @@
 import numbers
 import re
 
-import six
-
 import firebase_admin._messaging_utils as _messaging_utils
 
 
@@ -99,7 +97,7 @@ def check_string(cls, label, value, non_empty=False):
         """Checks if the given value is a string."""
         if value is None:
             return None
-        if not isinstance(value, six.string_types):
+        if not isinstance(value, str):
             if non_empty:
                 raise ValueError('{0} must be a non-empty string.'.format(label))
             raise ValueError('{0} must be a string.'.format(label))
@@ -122,10 +120,10 @@ def check_string_dict(cls, label, value):
             return None
         if not isinstance(value, dict):
             raise ValueError('{0} must be a dictionary.'.format(label))
-        non_str = [k for k in value if not isinstance(k, six.string_types)]
+        non_str = [k for k in value if not isinstance(k, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string keys.'.format(label))
-        non_str = [v for v in value.values() if not isinstance(v, six.string_types)]
+        non_str = [v for v in value.values() if not isinstance(v, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string values.'.format(label))
         return value
@@ -137,7 +135,7 @@ def check_string_list(cls, label, value):
             return None
         if not isinstance(value, list):
             raise ValueError('{0} must be a list of strings.'.format(label))
-        non_str = [k for k in value if not isinstance(k, six.string_types)]
+        non_str = [k for k in value if not isinstance(k, str)]
         if non_str:
             raise ValueError('{0} must not contain non-string values.'.format(label))
         return value
@@ -570,7 +568,7 @@ def encode_aps_sound(cls, sound):
         """Encodes an APNs sound configuration into JSON."""
         if sound is None:
             return None
-        if sound and isinstance(sound, six.string_types):
+        if sound and isinstance(sound, str):
             return sound
         if not isinstance(sound, _messaging_utils.CriticalSound):
             raise ValueError(
@@ -593,7 +591,7 @@ def encode_aps_alert(cls, alert):
         """Encodes an ``ApsAlert`` instance into JSON."""
         if alert is None:
             return None
-        if isinstance(alert, six.string_types):
+        if isinstance(alert, str):
             return alert
         if not isinstance(alert, _messaging_utils.ApsAlert):
             raise ValueError('Aps.alert must be a string or an instance of ApsAlert class.')

firebase_admin/_token_gen.py

@@ -19,7 +19,6 @@
 
 import cachecontrol
 import requests
-import six
 from google.auth import credentials
 from google.auth import iam
 from google.auth import jwt
@@ -149,7 +148,7 @@ def create_custom_token(self, uid, developer_claims=None):
                                          ', '.join(disallowed_keys)))
                 raise ValueError(error_message)
 
-        if not uid or not isinstance(uid, six.string_types) or len(uid) > 128:
+        if not uid or not isinstance(uid, str) or len(uid) > 128:
             raise ValueError('uid must be a string between 1 and 128 characters.')
 
         signing_provider = self.signing_provider
@@ -174,8 +173,8 @@ def create_custom_token(self, uid, developer_claims=None):
 
     def create_session_cookie(self, id_token, expires_in):
         """Creates a session cookie from the provided ID token."""
-        id_token = id_token.decode('utf-8') if isinstance(id_token, six.binary_type) else id_token
-        if not isinstance(id_token, six.text_type) or not id_token:
+        id_token = id_token.decode('utf-8') if isinstance(id_token, bytes) else id_token
+        if not isinstance(id_token, str) or not id_token:
             raise ValueError(
                 'Illegal ID token provided: {0}. ID token must be a non-empty '
                 'string.'.format(id_token))
@@ -256,8 +255,8 @@ def __init__(self, **kwargs):
 
     def verify(self, token, request):
         """Verifies the signature and data for the provided JWT."""
-        token = token.encode('utf-8') if isinstance(token, six.text_type) else token
-        if not isinstance(token, six.binary_type) or not token:
+        token = token.encode('utf-8') if isinstance(token, str) else token
+        if not isinstance(token, bytes) or not token:
             raise ValueError(
                 'Illegal {0} provided: {1}. {0} must be a non-empty '
                 'string.'.format(self.short_name, token))
@@ -308,7 +307,7 @@ def verify(self, token, request):
                 'Firebase {0} has incorrect "iss" (issuer) claim. Expected "{1}" but '
                 'got "{2}". {3} {4}'.format(self.short_name, expected_issuer, issuer,
                                             project_id_match_msg, verify_id_token_msg))
-        elif subject is None or not isinstance(subject, six.string_types):
+        elif subject is None or not isinstance(subject, str):
             error_message = (
                 'Firebase {0} has no "sub" (subject) claim. '
                 '{1}'.format(self.short_name, verify_id_token_msg))

firebase_admin/_user_mgt.py

@@ -16,9 +16,9 @@
 
 import base64
 import json
+from urllib import parse
+
 import requests
-import six
-from six.moves import urllib
 
 from firebase_admin import _auth_utils
 from firebase_admin import _user_import
@@ -397,7 +397,7 @@ def encode_action_code_settings(settings):
         raise ValueError("Dynamic action links url is mandatory")
 
     try:
-        parsed = urllib.parse.urlparse(settings.url)
+        parsed = parse.urlparse(settings.url)
         if not parsed.netloc:
             raise ValueError('Malformed dynamic action links url: "{0}".'.format(settings.url))
         parameters['continueUrl'] = settings.url
@@ -413,14 +413,14 @@ def encode_action_code_settings(settings):
 
     # dynamic_link_domain
     if settings.dynamic_link_domain is not None:
-        if not isinstance(settings.dynamic_link_domain, six.string_types):
+        if not isinstance(settings.dynamic_link_domain, str):
             raise ValueError('Invalid value provided for dynamic_link_domain: {0}'
                              .format(settings.dynamic_link_domain))
         parameters['dynamicLinkDomain'] = settings.dynamic_link_domain
 
     # ios_bundle_id
     if settings.ios_bundle_id is not None:
-        if not isinstance(settings.ios_bundle_id, six.string_types):
+        if not isinstance(settings.ios_bundle_id, str):
             raise ValueError('Invalid value provided for ios_bundle_id: {0}'
                              .format(settings.ios_bundle_id))
         parameters['iosBundleId'] = settings.ios_bundle_id
@@ -431,13 +431,13 @@ def encode_action_code_settings(settings):
         raise ValueError("Android package name is required when specifying other Android settings")
 
     if settings.android_package_name is not None:
-        if not isinstance(settings.android_package_name, six.string_types):
+        if not isinstance(settings.android_package_name, str):
             raise ValueError('Invalid value provided for android_package_name: {0}'
                              .format(settings.android_package_name))
         parameters['androidPackageName'] = settings.android_package_name
 
     if settings.android_minimum_version is not None:
-        if not isinstance(settings.android_minimum_version, six.string_types):
+        if not isinstance(settings.android_minimum_version, str):
             raise ValueError('Invalid value provided for android_minimum_version: {0}'
                              .format(settings.android_minimum_version))
         parameters['androidMinimumVersion'] = settings.android_minimum_version
@@ -486,7 +486,7 @@ def get_user(self, **kwargs):
     def list_users(self, page_token=None, max_results=MAX_LIST_USERS_RESULTS):
         """Retrieves a batch of users."""
         if page_token is not None:
-            if not isinstance(page_token, six.string_types) or not page_token:
+            if not isinstance(page_token, str) or not page_token:
                 raise ValueError('Page token must be a non-empty string.')
         if not isinstance(max_results, int):
             raise ValueError('Max results must be an integer.')

firebase_admin/_utils.py

@@ -14,13 +14,13 @@
 
 """Internal utilities common to all modules."""
 
+import io
 import json
 import socket
 
 import googleapiclient
 import httplib2
 import requests
-import six
 
 import firebase_admin
 from firebase_admin import exceptions
@@ -255,7 +255,7 @@ def handle_googleapiclient_error(error, message=None, code=None, http_response=N
 def _http_response_from_googleapiclient_error(error):
     """Creates a requests HTTP Response object from the given googleapiclient error."""
     resp = requests.models.Response()
-    resp.raw = six.BytesIO(error.content)
+    resp.raw = io.BytesIO(error.content)
     resp.status_code = error.resp.status
     return resp
 

firebase_admin/credentials.py

@@ -15,7 +15,6 @@
 """Firebase credentials module."""
 import collections
 import json
-import six
 
 import google.auth
 from google.auth.transport import requests
@@ -79,7 +78,7 @@ def __init__(self, cert):
           ValueError: If the specified certificate is invalid.
         """
         super(Certificate, self).__init__()
-        if isinstance(cert, six.string_types):
+        if isinstance(cert, str):
             with open(cert) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(cert, dict):
@@ -180,7 +179,7 @@ def __init__(self, refresh_token):
           ValueError: If the refresh token configuration is invalid.
         """
         super(RefreshToken, self).__init__()
-        if isinstance(refresh_token, six.string_types):
+        if isinstance(refresh_token, str):
             with open(refresh_token) as json_file:
                 json_data = json.load(json_file)
         elif isinstance(refresh_token, dict):