Added create_app_session_from_tty.

A utility to quickly set up input/output attached to the TTY.

Author: jonathanslenders

examples/prompts/enforce-tty-input-output.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+"""
+This will display a prompt that will always use the terminal for input and
+output, even if sys.stdin/stdout are connected to pipes.
+
+For testing, run as:
+    cat /dev/null | python ./enforce-tty-input-output.py > /dev/null
+"""
+from prompt_toolkit.application import create_app_session_from_tty
+from prompt_toolkit.shortcuts import prompt
+
+with create_app_session_from_tty():
+    prompt(">")

prompt_toolkit/application/__init__.py

@@ -2,6 +2,7 @@
 from .current import (
     AppSession,
     create_app_session,
+    create_app_session_from_tty,
     get_app,
     get_app_or_none,
     get_app_session,
@@ -17,6 +18,7 @@
     "AppSession",
     "get_app_session",
     "create_app_session",
+    "create_app_session_from_tty",
     "get_app",
     "get_app_or_none",
     "set_app",

prompt_toolkit/application/current.py

@@ -20,6 +20,7 @@
     "get_app_or_none",
     "set_app",
     "create_app_session",
+    "create_app_session_from_tty",
 ]
 
 
@@ -168,3 +169,29 @@ def create_app_session(
         yield session
     finally:
         _current_app_session.reset(token)
+
+
+@contextmanager
+def create_app_session_from_tty() -> Generator[AppSession, None, None]:
+    """
+    Create `AppSession` that always prefers the TTY input/output.
+
+    Even if `sys.stdin` and `sys.stdout` are connected to input/output pipes,
+    this will still use the terminal for interaction (because `sys.stderr` is
+    still connected to the terminal).
+
+    Usage::
+
+        from prompt_toolkit.shortcuts import prompt
+
+        with create_app_session_from_tty():
+            prompt('>')
+    """
+    from prompt_toolkit.input.defaults import create_input
+    from prompt_toolkit.output.defaults import create_output
+
+    input = create_input(always_prefer_tty=True)
+    output = create_output(always_prefer_tty=True)
+
+    with create_app_session(input=input, output=output) as app_session:
+        yield app_session