From 5990098ef81156508603a401c01da9aa30258079 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Mon, 20 Apr 2020 13:26:45 +0000
Subject: [PATCH] Add UserPassAuthenticator

---
 PFERD/__init__.py       |  4 --
 PFERD/authenticators.py | 81 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 4 deletions(-)
 create mode 100644 PFERD/authenticators.py

diff --git a/PFERD/__init__.py b/PFERD/__init__.py
index 18ec1c0..3f44c6e 100644
--- a/PFERD/__init__.py
+++ b/PFERD/__init__.py
@@ -1,9 +1,5 @@
 import logging
 
-# from .ilias import *
-# from .utils import *
-from .temp_folder import *
-
 STYLE = "{"
 FORMAT = "[{levelname:<7}] {message}"
 DATE_FORMAT = "%F %T"
diff --git a/PFERD/authenticators.py b/PFERD/authenticators.py
new file mode 100644
index 0000000..2f8da8c
--- /dev/null
+++ b/PFERD/authenticators.py
@@ -0,0 +1,81 @@
+import getpass
+from typing import Optional, Tuple
+
+
+class UserPassAuthenticator:
+
+    def __init__(self, username: Optional[str] = None, password: Optional[str] = None) -> None:
+        self._given_username = username
+        self._given_password = password
+
+        self._username = username
+        self._password = password
+
+    def get_credentials(self, reason: str) -> Tuple[str, str]:
+        """
+        Returns a tuple (username, password). Prompts user for username or
+        password when necessary. Must be called with a "reason" that will be
+        displayed in the credentials prompt.
+        """
+
+        if self._username is None and self._given_username is not None:
+            self._username = self._given_username
+
+        if self._password is None and self._given_password is not None:
+            self._password = self._given_password
+
+        if self._username is None or self._password is None:
+            print(f"Enter credentials ({reason})")
+
+        username: str
+        if self._username is None:
+            username = input("Username: ")
+            self._username = username
+        else:
+            username = self._username
+
+        password: str
+        if self._password is None:
+            password = getpass.getpass(prompt="Password: ")
+            self._password = password
+        else:
+            password = self._password
+
+        return (username, password)
+
+    @property
+    def username(self) -> str:
+        """
+        The username. Accessing this property may cause the authenticator to
+        prompt the user.
+        """
+
+        (username, _) = self.get_credentials()
+        return username
+
+    @property
+    def password(self) -> str:
+        """
+        The password. Accessing this property may cause the authenticator to
+        prompt the user.
+        """
+
+        (_, path) = self.get_credentials()
+        return password
+
+    def invalidate_credentials(self) -> None:
+        """
+        Marks the credentials as invalid. If only a username was supplied in
+        the constructor, assumes that the username is valid and only the
+        password is invalid. If only a password was supplied in the
+        constructor, assumes that the password is valid and only the username
+        is invalid. Otherwise, assumes that username and password are both
+        invalid.
+        """
+
+        self._username = None
+        self._password = None
+
+        if self._given_username is not None and self._given_password is not None:
+            self._given_username = None
+            self._given_password = None