- Coverage and docs updates for custom JSON class.

- Fork point: master now represents a future 1.4 release.

4 files changed, 108 insertions, 40 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 859dc7b74..0714f6940 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,22 +1,13 @@
 Next release
 ============
 
-Bug Fixes
----------
+Features
+--------
 
-- Add ``REMOTE_ADDR`` to the ``prequest`` WSGI environ dict for benefit of
-  the debug toolbar, which effectively requires it to be present to work
-  properly.
-
-- When an asset specification was used as a Mako ``renderer=`` argument and a
-  ``mako.modules_directory`` was specified, Pyramid would fail to render the
-  template and instead would raise an error when attempting to write the file
-  to the modules directory.  Example symptom: ``WindowsError: [Error 267] The
-  directory name is invalid:
-  'c:\\docume~1\\chrism\\locals~1\\temp\\tmp9jtjix\\pyramid.tests:fixtures'``.
-  We now replace the colon in the Mako module filename with a dollar sign, so
-  it can work on Windows. See https://github.com/Pylons/pyramid/issues/512
-  for more information.
+- Custom objects can be made easily JSON-serializable in Pyramid by defining
+  a ``__json__`` method on the object's class. This method should return
+  values natively serializable by ``json.dumps`` (such as ints, lists,
+  dictionaries, strings, and so forth).
 
 1.3 (2012-03-21)
 ================
diff --git a/docs/narr/renderers.rst b/docs/narr/renderers.rst
index 52e97d091..34bee3c7f 100644
--- a/docs/narr/renderers.rst
+++ b/docs/narr/renderers.rst
@@ -207,17 +207,13 @@ representing the JSON serialization of the return value:
    '{"content": "Hello!"}'
 
 The return value needn't be a dictionary, but the return value must contain
-values serializable by :func:`json.dumps`. Extra arguments can be passed
-to :func:`json.dumps` by overriding the default renderer. See
-:class:`pyramid.renderers.JSON` and
-:ref:`_adding_and_overriding_renderers` for more information.
-
-Custom objects can be easily serialized by defining a :func:`__json__` method
-on the object. This method should return values serializable by
-:func:`json_dumps`. By defining this method and using a :term:`JSON`
-renderer the :class:`pyramid.renderers.ObjectJSONEncoder` class will be used
-for encoding your object. If you later define your own custom encoder it will
-override :class:`pyramid.renderers.ObjectJSONEncoder`.
+values serializable by ``json.dumps``.
+
+.. note::
+
+   Extra arguments can be passed to ``json.dumps`` by overriding the default
+   ``json`` renderer. See :class:`pyramid.renderers.JSON` and
+   :ref:`adding_and_overriding_renderers` for more information.
 
 You can configure a view to use the JSON renderer by naming ``json`` as the
 ``renderer`` argument of a view configuration, e.g. by using
@@ -235,13 +231,57 @@ Views which use the JSON renderer can vary non-body response attributes by
 using the api of the ``request.response`` attribute.  See
 :ref:`request_response_attr`.
 
+.. _json_serializing_custom_objects:
+
+Serializing Custom Objects
+++++++++++++++++++++++++++
+
+Custom objects can be made easily JSON-serializable in Pyramid by defining a
+``__json__`` method on the object's class. This method should return values
+natively serializable by ``json.dumps`` (such as ints, lists, dictionaries,
+strings, and so forth).
+
+.. code-block:: python
+   :linenos:
+
+   from pyramid.view import view_config
+
+   class MyObject(object):
+       def __init__(self, x):
+           self.x = x
+
+       def __json__(self):
+           return {'x':self.x}
+
+   @view_config(renderer='json')
+   def objects(request):
+       return [MyObject(1), MyObject(2)]
+
+   # the JSON value returned by ``objects`` will be:
+   #    [{"x": 1}, {"x": 2}]
+
+.. note::
+
+   Honoring the ``__json__`` method of custom objects is a feature new in
+   Pyramid 1.4.
+
+.. warning::
+
+   The machinery which performs the ``__json__`` method-calling magic is in
+   the :class:`pyramid.renderers.ObjectJSONEncoder` class.  This class will
+   be used for encoding any non-basic Python object when you use the default
+   ```json`` or ``jsonp`` renderers.  But if you later define your own custom
+   JSON renderer and pass it a "cls" argument signifying a different encoder,
+   the encoder you pass will override Pyramid's use of
+   :class:`pyramid.renderers.ObjectJSONEncoder`.
+
 .. index::
    pair: renderer; JSONP
 
 .. _jsonp_renderer:
 
 JSONP Renderer
---------------
+~~~~~~~~~~~~~~
 
 .. note:: This feature is new in Pyramid 1.1.
 
@@ -306,6 +346,10 @@ The string ``callback=?`` above in the the ``url`` param to the JQuery
 a JSONP request; the ``callback`` parameter will be automatically filled
 in for you and used.
 
+The same custom-object serialization scheme defined used for a "normal" JSON
+renderer in :ref:`json_serializing_custom_objects` can be used when passing
+values to a JSONP renderer too.
+
 .. index::
    pair: renderer; chameleon
 
diff --git a/pyramid/renderers.py b/pyramid/renderers.py
index 859fd3953..0adadf726 100644
--- a/pyramid/renderers.py
+++ b/pyramid/renderers.py
@@ -158,21 +158,31 @@ def string_renderer_factory(info):
     return _render
 
 class ObjectJSONEncoder(json.JSONEncoder):
-    """ Encoder that is used by :class:`pyramid.renderers.JSON` and
-    :class:`pyramid.renderers.JSONP`.
+    """ The default JSON object encoder (a subclass of json.Encoder) used by
+    :class:`pyramid.renderers.JSON` and :class:`pyramid.renderers.JSONP`.  It
+    is used when an object returned from a view and presented to a JSON-based
+    renderer is not a builtin Python type otherwise serializable to JSON.
     
-    This encoder will look for a :meth:`__json__` method on an object
-    and use the return value when encoding the object to json
-    using :meth:`json_dumps`.
+    This ``json.Encoder`` subclass overrides the ``json.Encoder.default``
+    method.  The overridden method looks for a ``__json__`` attribute on the
+    object it is passed.  If it's found, the encoder will assume it's
+    callable, and will call it with no arguments to obtain a value.  The
+    overridden ``default`` method will then return that value (which must be
+    a JSON-serializable basic Python type).
+
+    If the object passed to the overridden ``default`` method has no
+    ``__json__`` attribute, the ``json.JSONEncoder.default`` method is called
+    with the object that it was passed (which will end up raising a
+    :exc:`TypeError`, as it would with any other unserializable type).
 
     This class will be used only when you set a JSON or JSONP
     renderer and you do not define your own custom encoder class.
 
-    .. note:: This feature is new in Pyramid 1.3.
+    .. note:: This feature is new in Pyramid 1.4.
     """
 
     def default(self, obj):
-        if hasattr(obj, '__json__') and callable(obj.__json__):
+        if hasattr(obj, '__json__'):
             return obj.__json__()
         return json.JSONEncoder.default(self, obj)
 
@@ -203,9 +213,12 @@ class JSON(object):
        def myview(request):
            return {'greeting':'Hello world'}
 
-    .. note:: This feature is new in Pyramid 1.3. Prior to 1.3 there was
-    no public API for supplying options to the underlying
-    :func:`json.dumps` without defining a custom renderer.
+    .. note::
+
+       This feature is new in Pyramid 1.4. Prior to 1.4 there was
+       no public API for supplying options to the underlying
+       :func:`json.dumps` without defining a custom renderer.
+
     """
 
     def __init__(self, **kw):
@@ -254,6 +267,20 @@ class JSONP(JSON):
        config = Configurator()
        config.add_renderer('jsonp', JSONP(param_name='callback'))
 
+    The class also accepts arbitrary keyword arguments; all keyword arguments
+    except ``param_name`` are passed to the ``json.dumps`` function as
+    keyword arguments:
+
+    .. code-block:: python
+
+       from pyramid.config import Configurator
+
+       config = Configurator()
+       config.add_renderer('jsonp', JSONP(param_name='callback', indent=4))
+    
+    .. note:: The ability of this class to accept a ``**kw`` in its
+       constructor is new as of Pyramid 1.4.
+
     Once this renderer is registered via
     :meth:`~pyramid.config.Configurator.add_renderer` as above, you can use
     ``jsonp`` as the ``renderer=`` parameter to ``@view_config`` or
diff --git a/pyramid/tests/test_renderers.py b/pyramid/tests/test_renderers.py
index 9d9e608f1..f03c7acda 100644
--- a/pyramid/tests/test_renderers.py
+++ b/pyramid/tests/test_renderers.py
@@ -374,9 +374,7 @@ class TestJSON(unittest.TestCase):
         from json import JSONEncoder
         class MyEncoder(JSONEncoder):
             def default(self, obj):
-                if isinstance(obj, datetime):
-                    return obj.isoformat()
-                return super(JSONEncoder, self).default(obj)
+                return obj.isoformat()
         now = datetime.utcnow()
         renderer = self._makeOne(cls=MyEncoder)(None)
         result = renderer({'a':now}, {})
@@ -394,6 +392,14 @@ class TestJSON(unittest.TestCase):
         result = renderer(objects, {})
         self.assertEqual(result, '[{"x": 1}, {"x": 2}]')
 
+    def test_with_object_encoder_no___json__(self):
+        class MyObject(object):
+            def __init__(self, x):
+                self.x = x
+        objects = [MyObject(1), MyObject(2)]
+        renderer = self._makeOne()(None)
+        self.assertRaises(TypeError, renderer, objects, {})
+
 class Test_string_renderer_factory(unittest.TestCase):
     def _callFUT(self, name):
         from pyramid.renderers import string_renderer_factory