1 files changed, 57 insertions, 0 deletions
diff --git a/python/flask/signals.py b/python/flask/signals.py
new file mode 100644
index 0000000..18f2630
--- /dev/null
+++ b/python/flask/signals.py
@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+"""
+    flask.signals
+    ~~~~~~~~~~~~~
+
+    Implements signals based on blinker if available, otherwise
+    falls silently back to a noop.
+
+    :copyright: © 2010 by the Pallets team.
+    :license: BSD, see LICENSE for more details.
+"""
+
+signals_available = False
+try:
+    from blinker import Namespace
+    signals_available = True
+except ImportError:
+    class Namespace(object):
+        def signal(self, name, doc=None):
+            return _FakeSignal(name, doc)
+
+    class _FakeSignal(object):
+        """If blinker is unavailable, create a fake class with the same
+        interface that allows sending of signals but will fail with an
+        error on anything else.  Instead of doing anything on send, it
+        will just ignore the arguments and do nothing instead.
+        """
+
+        def __init__(self, name, doc=None):
+            self.name = name
+            self.__doc__ = doc
+        def _fail(self, *args, **kwargs):
+            raise RuntimeError('signalling support is unavailable '
+                               'because the blinker library is '
+                               'not installed.')
+        send = lambda *a, **kw: None
+        connect = disconnect = has_receivers_for = receivers_for = \
+            temporarily_connected_to = connected_to = _fail
+        del _fail
+
+# The namespace for code signals.  If you are not Flask code, do
+# not put signals in here.  Create your own namespace instead.
+_signals = Namespace()
+
+
+# Core signals.  For usage examples grep the source code or consult
+# the API documentation in docs/api.rst as well as docs/signals.rst
+template_rendered = _signals.signal('template-rendered')
+before_render_template = _signals.signal('before-render-template')
+request_started = _signals.signal('request-started')
+request_finished = _signals.signal('request-finished')
+request_tearing_down = _signals.signal('request-tearing-down')
+got_request_exception = _signals.signal('got-request-exception')
+appcontext_tearing_down = _signals.signal('appcontext-tearing-down')
+appcontext_pushed = _signals.signal('appcontext-pushed')
+appcontext_popped = _signals.signal('appcontext-popped')
+message_flashed = _signals.signal('message-flashed')