feat: add cloudfront signer

@@ -122,3 +122,9 @@ USE_TZ = True
 # https://docs.djangoproject.com/en/1.11/howto/static-files/
 
 STATIC_URL = '/static/'
+
+
+# Custom Settings
+CDN_PATH = 'https://khubox-files.khunet.net'
+CLOUDFRONT_KEY_ID = 'APKAJ3FOBWI34OZJTXJQ'
+CLOUDFRONT_KEY_PRIVATE = '-----BEGIN RSA PRIVATE KEY-----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\nUUFBsDEkWlkoAmfPkcrrq9cLJlmSNt3ehQj4p5iAJwoVBXXa++PO\n-----END RSA PRIVATE KEY-----'

+import datetime
+from botocore.signers import CloudFrontSigner
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes, serialization
+from cryptography.hazmat.primitives.asymmetric import padding
+from django.conf import settings
+
+
+def rsa_signer(message):
+    private_key = serialization.load_pem_private_key(
+        settings.CLOUDFRONT_KEY_PRIVATE.encode('ascii'),
+        password=None,
+        backend=default_backend()
+    )
+    return private_key.sign(message, padding.PKCS1v15(), hashes.SHA1())
+
+
+def sign(url):
+    expire_date = datetime.datetime(2020, 6, 10)
+    cloudfront_signer = CloudFrontSigner(settings.CLOUDFRONT_KEY_ID, rsa_signer)
+    signed_url = cloudfront_signer.generate_presigned_url(url, date_less_than=expire_date)
+    return signed_url