Added wrapper module around simplejson/json for much simplified customization.

flask/json.py

@@ -0,0 +1,146 @@
+# -*- coding: utf-8 -*-
+"""
+    flask.jsonimpl
+    ~~~~~~~~~~~~~~
+
+    Implementation helpers for the JSON support in Flask.
+
+    :copyright: (c) 2012 by Armin Ronacher.
+    :license: BSD, see LICENSE for more details.
+"""
+from datetime import datetime
+from .globals import current_app, request
+
+from werkzeug.http import http_date
+
+# Use the same json implementation as itsdangerous on which we
+# depend anyways.
+from itsdangerous import simplejson as _json
+
+
+# figure out if simplejson escapes slashes.  This behavior was changed
+# from one version to another without reason.
+_slash_escape = '\\/' not in _json.dumps('/')
+
+
+__all__ = ['dump', 'dumps', 'load', 'loads', 'htmlsafe_dump',
+           'htmlsafe_dumps', 'JSONDecoder', 'JSONEncoder',
+           'jsonify']
+
+
+class JSONEncoder(_json.JSONEncoder):
+    """The default Flask JSON encoder.  This one extends the default simplejson
+    encoder by also supporting ``datetime`` objects as well as ``Markup``
+    objects which are serialized as RFC 822 datetime strings (same as the HTTP
+    date format).  In order to support more data types override the
+    :meth:`default` method.
+    """
+
+    def default(self, o):
+        """Implement this method in a subclass such that it returns a
+        serializable object for ``o``, or calls the base implementation (to
+        raise a ``TypeError``).
+
+        For example, to support arbitrary iterators, you could implement
+        default like this::
+
+            def default(self, o):
+                try:
+                    iterable = iter(o)
+                except TypeError:
+                    pass
+                else:
+                    return list(iterable)
+                return JSONEncoder.default(self, o)
+        """
+        if isinstance(o, datetime):
+            return http_date(o)
+        if hasattr(o, '__html__'):
+            return unicode(o.__html__())
+        return _json.JSONEncoder.default(self, o)
+
+
+class JSONDecoder(_json.JSONDecoder):
+    """The default JSON decoder.  This one does not change the behavior from
+    the default simplejson encoder.  Consult the :mod:`json` documentation
+    for more information.  This decoder is not only used for the load
+    functions of this module but also :attr:`~flask.Request`.
+    """
+
+
+def dumps(obj, **kwargs):
+    """Serialize ``obj`` to a JSON formatted ``str`` by using the application's
+    configured encoder (:attr:`~flask.Flask.json_encoder`).
+    """
+    kwargs.setdefault('cls', current_app.json_encoder)
+    return _json.dumps(obj, **kwargs)
+
+
+def dump(obj, fp, **kwargs):
+    """Like :func:`dumps` but writes into a file object."""
+    kwargs.setdefault('cls', current_app.json_encoder)
+    return _json.dump(obj, fp, **kwargs)
+
+
+def loads(s, **kwargs):
+    """Unserialize a JSON object from a string ``s`` by using the application's
+    configured decoder (:attr:`~flask.Flask.json_decoder`).
+    """
+    kwargs.setdefault('cls', current_app.json_decoder)
+    return _json.loads(s, **kwargs)
+
+
+def load(fp, **kwargs):
+    """Like :func:`loads` but reads from a file object.
+    """
+    kwargs.setdefault('cls', current_app.json_decoder)
+    return _json.load(fp, **kwargs)
+
+
+def htmlsafe_dumps(obj, **kwargs):
+    """Works exactly like :func:`dumps` but is safe for use in ``<script>``
+    tags.  It accepts the same arguments and returns a JSON string.  Note that
+    this is available in templates through the ``|tojson`` filter but it will
+    have to be wrapped in ``|safe`` unless **true** XHTML is being used.
+    """
+    rv = dumps(obj, **kwargs)
+    if _slash_escape:
+        rv = rv.replace('/', '\\/')
+    return rv.replace('<!', '<\\u0021')
+
+
+def htmlsafe_dump(obj, fp, **kwargs):
+    """Like :func:`htmlsafe_dumps` but writes into a file object."""
+    fp.write(htmlsafe_dumps(obj, **kwargs))
+
+
+def jsonify(*args, **kwargs):
+    """Creates a :class:`~flask.Response` with the JSON representation of
+    the given arguments with an `application/json` mimetype.  The arguments
+    to this function are the same as to the :class:`dict` constructor.
+
+    Example usage::
+
+        @app.route('/_get_current_user')
+        def get_current_user():
+            return jsonify(username=g.user.username,
+                           email=g.user.email,
+                           id=g.user.id)
+
+    This will send a JSON response like this to the browser::
+
+        {
+            "username": "admin",
+            "email": "admin@localhost",
+            "id": 42
+        }
+
+    This requires Python 2.6 or an installed version of simplejson.  For
+    security reasons only objects are supported toplevel.  For more
+    information about this, have a look at :ref:`json-security`.
+
+    .. versionadded:: 0.2
+    """
+    return current_app.response_class(dumps(dict(*args, **kwargs),
+        indent=None if request.is_xhr else 2),
+        mimetype='application/json')