From 37fc626ffd53f95d186974608ed6ee4c71e8f10d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Langa?= <lukasz@langa.pl>
Date: Fri, 13 Jan 2017 13:36:34 -0800
Subject: [PATCH] Add type signature for a WSGI Application to wsgiref (#825)

This type is something core to Python and is useful when typing web applications,
but doesn't actually exist in the stdlib anywhere.  I put this in wsgiref, but I am
open to suggestions as for a better place.

(Original PR by @rowillia.)
---
 stdlib/2/wsgiref/types.pyi | 34 ++++++++++++++++++++++++++++++++++
 stdlib/3/wsgiref/types.pyi | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 stdlib/2/wsgiref/types.pyi
 create mode 100644 stdlib/3/wsgiref/types.pyi

diff --git a/stdlib/2/wsgiref/types.pyi b/stdlib/2/wsgiref/types.pyi
new file mode 100644
index 000000000..7c28415bb
--- /dev/null
+++ b/stdlib/2/wsgiref/types.pyi
@@ -0,0 +1,34 @@
+# Type declaration for a WSGI Function in Python 2
+#
+# wsgiref/types.py doesn't exist and neither does WSGIApplication, it's a type
+# provided for type checking purposes.
+#
+# This means you cannot simply import wsgiref.types in your code. Instead,
+# use the `TYPE_CHECKING` flag from the typing module:
+#
+#   from typing import TYPE_CHECKING
+#
+#   if TYPE_CHECKING:
+#       from wsgiref.types import WSGIApplication
+#
+# This import is now only taken into account by the type checker. Consequently,
+# you need to use 'WSGIApplication' and not simply WSGIApplication when type
+# hinting your code.  Otherwise Python will raise NameErrors.
+
+from typing import Callable, Dict, Iterable, List, Optional, Tuple, Type, Union
+from types import TracebackType
+
+_exc_info = Tuple[Optional[Type[BaseException]],
+                  Optional[BaseException],
+                  Optional[TracebackType]]
+_Text = Union[unicode, str]
+WSGIApplication = Callable[
+    [
+        Dict[_Text, _Text],
+        Union[
+            Callable[[_Text, List[Tuple[_Text, _Text]]], Callable[[_Text], None]],
+            Callable[[_Text, List[Tuple[_Text, _Text]], _exc_info], Callable[[_Text], None]],
+        ]
+    ],
+    Iterable[_Text]
+]
diff --git a/stdlib/3/wsgiref/types.pyi b/stdlib/3/wsgiref/types.pyi
new file mode 100644
index 000000000..f9df8084c
--- /dev/null
+++ b/stdlib/3/wsgiref/types.pyi
@@ -0,0 +1,33 @@
+# Type declaration for a WSGI Function in Python 3
+#
+# wsgiref/types.py doesn't exist and neither does WSGIApplication, it's a type
+# provided for type checking purposes.
+#
+# This means you cannot simply import wsgiref.types in your code. Instead,
+# use the `TYPE_CHECKING` flag from the typing module:
+#
+#   from typing import TYPE_CHECKING
+#
+#   if TYPE_CHECKING:
+#       from wsgiref.types import WSGIApplication
+#
+# This import is now only taken into account by the type checker. Consequently,
+# you need to use 'WSGIApplication' and not simply WSGIApplication when type
+# hinting your code.  Otherwise Python will raise NameErrors.
+
+from typing import Callable, Dict, Iterable, List, Optional, Tuple, Type, Union
+from types import TracebackType
+
+_exc_info = Tuple[Optional[Type[BaseException]],
+                  Optional[BaseException],
+                  Optional[TracebackType]]
+WSGIApplication = Callable[
+    [
+        Dict[str, str],
+        Union[
+            Callable[[str, List[Tuple[str, str]]], Callable[[Union[bytes, str]], None]],
+            Callable[[str, List[Tuple[str, str]], _exc_info], Callable[[Union[bytes, str]], None]],
+        ]
+    ],
+    Iterable[Union[bytes, str]],
+]