CredentialManager: Store passwords in system keyring

Credential Manager is used for safely storing passwords in system's keyring services.

Orange/widgets/credentials.py

@@ -0,0 +1,26 @@
+import keyring
+
+SERVICE_NAME = 'Orange3 - {}'
+
+
+class CredentialManager:
+    def __init__(self, username):
+        """
+        Class for storing passwords in the system keyring service.
+
+        Args:
+            username: username used for storing a matching password.
+        """
+        self.username = username
+        self.service_name = SERVICE_NAME.format(self.username)
+
+    @property
+    def key(self):
+        return keyring.get_password(self.service_name, self.username)
+
+    @key.setter
+    def key(self, value):
+        keyring.set_password(self.service_name, self.username, value)
+
+    def delete_password(self):
+        keyring.delete_password(self.service_name, self.username)

Orange/widgets/tests/test_credentials.py

@@ -0,0 +1,12 @@
+import unittest
+
+from Orange.widgets.credentials import CredentialManager
+
+
+class CredentialManagerTests(unittest.TestCase):
+    def test_credential_manager(self):
+        cm = CredentialManager('Foo')
+        cm.key = 'Bar'
+        self.assertEqual(cm.key, 'Bar')
+        cm.delete_password()
+        self.assertEqual(cm.key, None)