Allow interactive flow to be aborted by CTRL+C even when running on Windows

msal/oauth2cli/authcode.py

@@ -8,6 +8,8 @@
 import logging
 import socket
 from string import Template
+import threading
+import time
 
 try:  # Python 3
     from http.server import HTTPServer, BaseHTTPRequestHandler
@@ -149,11 +151,7 @@ def get_port(self):
         # https://docs.python.org/2.7/library/socketserver.html#SocketServer.BaseServer.server_address
         return self._server.server_address[1]
 
-    def get_auth_response(self, auth_uri=None, timeout=None, state=None,
-            welcome_template=None, success_template=None, error_template=None,
-            auth_uri_callback=None,
-            browser_name=None,
-            ):
+    def get_auth_response(self, timeout=None, **kwargs):
         """Wait and return the auth response. Raise RuntimeError when timeout.
 
         :param str auth_uri:
@@ -192,6 +190,37 @@ def get_auth_response(self, auth_uri=None, timeout=None, state=None,
             and https://openid.net/specs/openid-connect-core-1_0.html#AuthResponse
             Returns None when the state was mismatched, or when timeout occurred.
         """
+        # Historically, the _get_auth_response() uses HTTPServer.handle_request(),
+        # because its handle-and-retry logic is conceptually as easy as a while loop.
+        # Also, handle_request() honors server.timeout setting, and CTRL+C simply works.
+        # All those are true when running on Linux.
+        #
+        # However, the behaviors on Windows turns out to be different.
+        # A socket server waiting for request would freeze the current thread.
+        # Neither timeout nor CTRL+C would work. End user would have to do CTRL+BREAK.
+        # https://stackoverflow.com/questions/1364173/stopping-python-using-ctrlc
+        #
+        # The solution would need to somehow put the http server into its own thread.
+        # This could be done by the pattern of ``http.server.test()`` which internally
+        # use ``ThreadingHTTPServer.serve_forever()`` (only available in Python 3.7).
+        # Or create our own thread to wrap the HTTPServer.handle_request() inside.
+        result = {}  # A mutable object to be filled with thread's return value
+        t = threading.Thread(
+            target=self._get_auth_response, args=(result,), kwargs=kwargs)
+        t.daemon = True  # So that it won't prevent the main thread from exiting
+        t.start()
+        begin = time.time()
+        while (time.time() - begin < timeout) if timeout else True:
+            time.sleep(1)  # Short detection interval to make happy path responsive
+            if not t.is_alive():  # Then the thread has finished its job and exited
+                break
+        return result or None
+
+    def _get_auth_response(self, result, auth_uri=None, timeout=None, state=None,
+            welcome_template=None, success_template=None, error_template=None,
+            auth_uri_callback=None,
+            browser_name=None,
+            ):
         welcome_uri = "http://localhost:{p}".format(p=self.get_port())
         abort_uri = "{loc}?error=abort".format(loc=welcome_uri)
         logger.debug("Abort by visit %s", abort_uri)
@@ -238,7 +267,7 @@ def get_auth_response(self, auth_uri=None, timeout=None, state=None,
                     logger.debug("State mismatch. Ignoring this noise.")
                 else:
                     break
-        return self._server.auth_response
+        result.update(self._server.auth_response)  # Return via writable result param
 
     def close(self):
         """Either call this eventually; or use the entire class as context manager"""

msal/oauth2cli/oauth2.py

@@ -199,7 +199,7 @@ def _obtain_token(  # The verb "obtain" is influenced by OAUTH2 RFC 6749
             _data["client_assertion"] = encoder(
                 self.client_assertion()  # Do lazy on-the-fly computation
                 if callable(self.client_assertion) else self.client_assertion
-                )   # The type is bytes, which is preferrable. See also:
+                )   # The type is bytes, which is preferable. See also:
                     # https://github.com/psf/requests/issues/4503#issuecomment-455001070
 
         _data.update(self.default_body)  # It may contain authen parameters