Make some dependencies optional

docs/index.rst

@@ -1135,6 +1135,9 @@ displayed.
 
 Mastodon allows an application to have one webpush subscription per user at a time.
 
+All crypto utilities require Mastodon.pys optional "webpush" feature dependencies
+(specifically, the "cryptography" and "http_ece" packages).
+
 .. automethod:: Mastodon.push_subscription
 .. automethod:: Mastodon.push_subscription_set
 .. automethod:: Mastodon.push_subscription_update

mastodon/Mastodon.py

@@ -20,9 +20,20 @@ import threading
 import sys
 import six
 from decorator import decorate
-from cryptography.hazmat.backends import default_backend
-from cryptography.hazmat.primitives.asymmetric import ec
-import http_ece
+
+IMPL_HAS_CRYPTO = True
+try:
+    from cryptography.hazmat.backends import default_backend
+    from cryptography.hazmat.primitives.asymmetric import ec
+except:
+    IMPL_HAS_CRYPTO = False
+    
+IMPL_HAS_ECE = True    
+try:
+    import http_ece
+except:
+    IMPL_HAS_ECE = False
+
 import base64
 import json
 import blurhash
@@ -2306,6 +2317,9 @@ class Mastodon:
         Returns two dicts: One with the private key and shared secret and another with the 
         public key and shared secret.
         """
+        if not IMPL_HAS_CRYPTO:
+            raise NotImplementedError('To use the crypto tools, please install the webpush feature dependencies.')
+        
         push_key_pair = ec.generate_private_key(ec.SECP256R1(), default_backend())
         push_key_priv = push_key_pair.private_numbers().private_value
         push_key_pub = push_key_pair.public_key().public_numbers().encode_point() 
@@ -2331,6 +2345,9 @@ class Mastodon:
         
         Returns the decoded webpush as a `push notification dict`_.
         """
+        if (not IMPL_HAS_ECE) or (not IMPL_HAS_CRYPTO):
+            raise NotImplementedError('To use the crypto tools, please install the webpush feature dependencies.')
+        
         salt = self.__decode_webpush_b64(encryption_header.split("salt=")[1].strip())
         dhparams = self.__decode_webpush_b64(crypto_key_header.split("dh=")[1].split(";")[0].strip())
         p256ecdsa = self.__decode_webpush_b64(crypto_key_header.split("p256ecdsa=")[1].strip())

setup.py

@@ -1,12 +1,27 @@
 from setuptools import setup
 
-test_deps = ['pytest', 'pytest-runner', 'pytest-cov', 'vcrpy', 'pytest-vcr', 'pytest-mock', 'requests-mock']
+test_deps = [
+    'pytest', 
+    'pytest-runner', 
+    'pytest-cov', 
+    'vcrpy', 
+    'pytest-vcr', 
+    'pytest-mock', 
+    'requests-mock'
+]
+
+webpush_deps = [
+    'http_ece>=1.0.5',
+    'cryptography>=1.6.0',
+]
+
 extras = {
-      "test": test_deps
+      "test": test_deps,
+      "webpush": webpush_deps,
 }
 
 setup(name='Mastodon.py',
-      version='1.4.2',
+      version='1.4.3',
       description='Python wrapper for the Mastodon API',
       packages=['mastodon'],
       install_requires=[
@@ -16,8 +31,6 @@ setup(name='Mastodon.py',
           'pytz',
           'python-magic',
           'decorator>=4.0.0', 
-          'http_ece>=1.0.5',
-          'cryptography>=1.6.0',
           'blurhash>=1.1.3',
       ],
       tests_require=test_deps,