Lazy load dependencies

Author: rayluo

msal/application.py

@@ -11,8 +11,6 @@
 from threading import Lock
 import os
 
-import requests
-
 from .oauth2cli import Client, JwtAssertionCreator
 from .oauth2cli.oidc import decode_part
 from .authority import Authority
@@ -425,6 +423,8 @@ def __init__(
         if http_client:
             self.http_client = http_client
         else:
+            import requests  # Lazy load
+
             self.http_client = requests.Session()
             self.http_client.verify = verify
             self.http_client.proxies = proxies

msal/authority.py

@@ -5,11 +5,6 @@
     from urlparse import urlparse
 import logging
 
-# Historically some customers patched this module-wide requests instance.
-# We keep it here for now. They will be removed in next major release.
-import requests
-import requests as _requests
-
 from .exceptions import MsalServiceError
 
 
@@ -59,9 +54,10 @@ class Authority(object):
     _domains_without_user_realm_discovery = set([])
 
     @property
-    def http_client(self):  # Obsolete. We will remove this in next major release.
-        # A workaround: if module-wide requests is patched, we honor it.
-        return self._http_client if requests is _requests else requests
+    def http_client(self):  # Obsolete. We will remove this eventually
+        warnings.warn(
+            "authority.http_client might be removed in MSAL Python 1.21+", DeprecationWarning)
+        return self._http_client
 
     def __init__(self, authority_url, http_client, validate_authority=True):
         """Creates an authority instance, and also validates it.
@@ -84,7 +80,7 @@ def __init__(self, authority_url, http_client, validate_authority=True):
             payload = instance_discovery(
                 "https://{}{}/oauth2/v2.0/authorize".format(
                     self.instance, authority.path),
-                self.http_client)
+                self._http_client)
             if payload.get("error") == "invalid_instance":
                 raise ValueError(
                     "invalid_instance: "
@@ -104,7 +100,7 @@ def __init__(self, authority_url, http_client, validate_authority=True):
         try:
             openid_config = tenant_discovery(
                 tenant_discovery_endpoint,
-                self.http_client)
+                self._http_client)
         except ValueError:
             raise ValueError(
                 "Unable to get authority configuration for {}. "
@@ -124,7 +120,7 @@ def user_realm_discovery(self, username, correlation_id=None, response=None):
         # "federation_protocol", "cloud_audience_urn",
         # "federation_metadata_url", "federation_active_auth_url", etc.
         if self.instance not in self.__class__._domains_without_user_realm_discovery:
-            resp = response or self.http_client.get(
+            resp = response or self._http_client.get(
                 "https://{netloc}/common/userrealm/{username}?api-version=1.0".format(
                     netloc=self.instance, username=username),
                 headers={'Accept': 'application/json',

msal/oauth2cli/assertion.py

@@ -4,8 +4,6 @@
 import uuid
 import logging
 
-import jwt
-
 
 logger = logging.getLogger(__name__)
 
@@ -99,6 +97,7 @@ def create_normal_assertion(
         Parameters are defined in https://tools.ietf.org/html/rfc7523#section-3
         Key-value pairs in additional_claims will be added into payload as-is.
         """
+        import jwt  # Lazy loading
         now = time.time()
         payload = {
             'aud': audience,

msal/oauth2cli/oauth2.py

@@ -17,8 +17,6 @@
 import string
 import hashlib
 
-import requests
-
 from .authcode import AuthCodeReceiver as _AuthCodeReceiver
 
 try:
@@ -159,6 +157,8 @@ def __init__(
                     "when http_client is in use")
             self._http_client = http_client
         else:
+            import requests  # Lazy loading
+
             self._http_client = requests.Session()
             self._http_client.verify = True if verify is None else verify
             self._http_client.proxies = proxies