From a958a7b285f8b763324fd3df3000a7f781cfdc91 Mon Sep 17 00:00:00 2001
From: Lance Edgar <lance@edbob.org>
Date: Fri, 21 Feb 2014 10:10:10 -0800
Subject: [PATCH] Add event hook for attaching Rattail `config` to new
 requests.

---
 docs/api/subscribers.rst  |  7 +++++++
 docs/index.rst            |  8 ++++++--
 tailbone/subscribers.py   | 30 ++++++++++++++++++++++++++++++
 tests/test_subscribers.py | 28 +++++++++++++++++++++++++++-
 4 files changed, 70 insertions(+), 3 deletions(-)
 create mode 100644 docs/api/subscribers.rst

diff --git a/docs/api/subscribers.rst b/docs/api/subscribers.rst
new file mode 100644
index 00000000..abafe0c9
--- /dev/null
+++ b/docs/api/subscribers.rst
@@ -0,0 +1,7 @@
+
+``tailbone.subscribers``
+========================
+
+.. automodule:: tailbone.subscribers
+
+.. autofunction:: add_rattail_config_attribute_to_request
diff --git a/docs/index.rst b/docs/index.rst
index f5b66144..19c21af6 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -5,13 +5,17 @@ Tailbone
 Welcome to Tailbone, part of the Rattail project.
 
 The documentation you are currently reading is for the Tailbone web application
-package. More information is (sort of) available at http://rattail.edbob.org/.
+package. More information is (sort of) available at http://rattailproject.org/.
 
-Contents:
+Clearly not everything is documented yet.  Below you can see what has received
+some attention thus far.
+
+API:
 
 .. toctree::
    :maxdepth: 2
 
+   api/subscribers
 
 
 Indices and tables
diff --git a/tailbone/subscribers.py b/tailbone/subscribers.py
index eea4f403..890d6809 100644
--- a/tailbone/subscribers.py
+++ b/tailbone/subscribers.py
@@ -36,6 +36,35 @@ from rattail.db.model import User
 from rattail.db.auth import has_permission
 
 
+def add_rattail_config_attribute_to_request(event):
+    """
+    Add a ``rattail_config`` attribute to a request object.
+
+    This function is really just a matter of convenience, but it should help to
+    make other code more terse (example below).  It is designed to act as a
+    subscriber to the Pyramid ``NewRequest`` event.
+
+    A global Rattail ``config`` should already be present within the Pyramid
+    application registry's settings, which would normally be accessed via::
+    
+       request.registry.settings['rattail_config']
+
+    This function merely "promotes" this config object so that it is more
+    directly accessible, a la::
+
+       request.rattail_config
+
+    .. note::
+       All this of course assumes that a Rattail ``config`` object *has* in
+       fact already been placed in the application registry settings.  If this
+       is not the case, this function will do nothing.
+    """
+    request = event.request
+    rattail_config = request.registry.settings.get('rattail_config')
+    if rattail_config:
+        request.rattail_config = rattail_config
+
+
 def before_render(event):
     """
     Adds goodies to the global template renderer context.
@@ -96,5 +125,6 @@ def context_found(event):
 
 
 def includeme(config):
+    config.add_subscriber(add_rattail_config_attribute_to_request, 'pyramid.events.NewRequest')
     config.add_subscriber(before_render, 'pyramid.events.BeforeRender')
     config.add_subscriber(context_found, 'pyramid.events.ContextFound')
diff --git a/tests/test_subscribers.py b/tests/test_subscribers.py
index 7e63b7c7..4317a262 100644
--- a/tests/test_subscribers.py
+++ b/tests/test_subscribers.py
@@ -1,7 +1,9 @@
 
+from unittest import TestCase
+
 from mock import Mock
+from pyramid import testing
 
-from . import TestCase
 from tailbone import subscribers
 
 
@@ -11,3 +13,27 @@ class SubscribersTests(TestCase):
         event = Mock()
         event.__setitem__ = Mock()
         subscribers.before_render(event)
+
+
+class TestAddRattailConfigAttributeToRequest(TestCase):
+
+    def test_nothing_is_done_if_no_config_in_registry_settings(self):
+        request = testing.DummyRequest()
+        config = testing.setUp(request=request)
+        self.assertFalse('rattail_config' in request.registry.settings)
+        self.assertFalse(hasattr(request, 'rattail_config'))
+        event = Mock(request=request)
+        subscribers.add_rattail_config_attribute_to_request(event)
+        self.assertFalse(hasattr(request, 'rattail_config'))
+        testing.tearDown()
+
+    def test_attribute_added_if_config_present_in_registry_settings(self):
+        rattail_config = Mock()
+        request = testing.DummyRequest()
+        config = testing.setUp(request=request, settings={'rattail_config': rattail_config})
+        self.assertTrue('rattail_config' in request.registry.settings)
+        self.assertFalse(hasattr(request, 'rattail_config'))
+        event = Mock(request=request)
+        subscribers.add_rattail_config_attribute_to_request(event)
+        self.assertTrue(request.rattail_config is rattail_config)
+        testing.tearDown()