Add sprockets.mixins.mediatype.transcoders.JSONTranscoder.

docs/api.rst

@@ -19,3 +19,10 @@ Content Type Registration
 
 .. autoclass:: ContentSettings
    :members:
+
+Bundled Transcoders
+-------------------
+.. currentmodule:: sprockets.mixins.mediatype.transcoders
+
+.. autoclass:: JSONTranscoder
+   :members:

docs/history.rst

@@ -6,6 +6,7 @@ Version History
 - Repackage from a module into a package.  Distributing raw modules inside
   of a namespace package is unreliable and questionably correct.
 - Add :func:`sprockets.mixins.mediatype.content.add_transcoder`.
+- Add :class:`sprockets.mixins.mediatype.transcoders.JSONTranscoder`
 
 `1.0.4`_ (14 Sep 2015)
 ----------------------

examples.py

@@ -1,8 +1,7 @@
-import json
 import logging
 import signal
 
-from sprockets.mixins.mediatype import content
+from sprockets.mixins.mediatype import content, transcoders
 from tornado import ioloop, web
 import msgpack
 
@@ -22,8 +21,8 @@ def make_application(**settings):
                                      encoding='utf-8')
     content.add_binary_content_type(application, 'application/msgpack',
                                     msgpack.packb, msgpack.unpackb)
-    content.add_text_content_type(application, 'application/json', 'utf-8',
-                                  json.dumps, json.loads)
+    content.add_transcoder(application, 'application/json',
+                           transcoders.JSONTranscoder())
     return application
 
 

sprockets/mixins/mediatype/transcoders.py

@@ -0,0 +1,56 @@
+"""Bundled media type transcoders."""
+import json
+import uuid
+
+from sprockets.mixins.mediatype import handlers
+
+
+class JSONTranscoder(handlers.TextContentHandler):
+    """
+    JSON transcoder instance.
+
+    :param str content_type: the content type that this encoder instance
+        implements. If omitted, ``application/json`` is used. This is
+        passed directly to the ``TextContentHandler`` initializer.
+    :param str default_encoding: the encoding to use if none is specified.
+        If omitted, this defaults to ``utf-8``. This is passed directly to
+        the ``TextContentHandler`` initializer.
+
+    .. attribute:: dump_options
+
+       Keyword parameters that are passed to :func:`json.dumps` when
+       :meth:`.dumps` is called.
+
+    .. attribute:: load_options
+
+       Keyword parameters that are passed to :func:`json.loads` when
+       :meth:`.loads` is called.
+
+    """
+
+    def __init__(self, content_type='application/json',
+                 default_encoding='utf-8'):
+        super(JSONTranscoder, self).__init__(content_type, self.dumps,
+                                             self.loads, default_encoding)
+        self.dump_options = {}
+        self.load_options = {}
+
+    def dumps(self, obj):
+        """
+        Dump a :class:`object` instance into a JSON :class:`str`
+
+        :param object obj: the object to dump
+        :return: the JSON representation of :class:`object`
+
+        """
+        return json.dumps(obj, **self.dump_options)
+
+    def loads(self, str_repr):
+        """
+        Transform :class:`str` into an :class:`object` instance.
+
+        :param str str_repr: the UNICODE representation of an object
+        :return: the decoded :class:`object` representation
+
+        """
+        return json.loads(str_repr, **self.load_options)