Added JSON Support and started working on jQuery docs

docs/api.rst

@@ -56,12 +56,15 @@ Incoming Request Data
 
    .. attribute:: stream
 
-      If the incoming form data was not encoded with a known encoding (for
-      example it was transmitted as JSON) the data is stored unmodified in
-      this stream for consumption.  For example to read the incoming
-      request data as JSON, one can do the following::
+      If the incoming form data was not encoded with a known mimetype
+      the data is stored unmodified in this stream for consumption.  Most
+      of the time it is a better idea to use :attr:`data` which will give
+      you that data as a string.  The stream only returns the data once.
+
+   .. attribute:: data
 
-          json_body = simplejson.load(request.stream)
+      Contains the incoming request data as string in case it came with
+      a mimetype Flask does not handle.
 
    .. attribute:: files
 
@@ -106,6 +109,20 @@ Incoming Request Data
       `root_url`    ``http://www.example.com/myapplication/``
       ============= ======================================================
 
+   .. attribute:: is_xhr
+
+      `True` if the request was triggered via a JavaScript
+      `XMLHttpRequest`. This only works with libraries that support the
+      ``X-Requested-With`` header and set it to `XMLHttpRequest`.
+      Libraries that do that are prototype, jQuery and Mochikit and
+      probably some more.
+
+   .. attribute:: json
+
+      Contains the parsed body of the JSON request if the mimetype of
+      the incoming data was `application/json`.  This requires Python 2.6
+      or an installed version of simplejson.
+
 Response Objects
 ----------------
 
@@ -201,6 +218,38 @@ Message Flashing
 
 .. autofunction:: get_flashed_messages
 
+Returning JSON
+--------------
+
+.. autofunction:: jsonify
+
+.. data:: json
+
+    If JSON support is picked up, this will be the module that Flask is
+    using to parse and serialize JSON.  So instead of doing this yourself::
+
+        try:
+            import simplejson as json
+        except ImportError:
+            import json
+
+    You can instead just do this::
+
+        from flask import json
+
+    For usage examples, read the :mod:`json` documentation.
+
+    The :func:`~json.dumps` function of this json module is also available
+    as filter called ``|tojson`` in Jinja2.  Note that inside `script`
+    tags no escaping must take place, so make sure to disable escaping
+    with ``|safe`` if you intend to use it inside `script` tags:
+
+    .. sourcecode:: html+jinja
+
+        <script type=text/javascript>
+            doSomethingWith({{ user.username|tojson|safe }});
+        </script>
+
 Template Rendering
 ------------------
 

docs/patterns/index.rst

@@ -19,3 +19,4 @@ end of the request, the database connection is closed again.
    wtforms
    templateinheritance
    flashing
+   jquery

docs/patterns/jquery.rst

@@ -0,0 +1,59 @@
+AJAX With jQuery
+================
+
+`jQuery`_ is a small JavaScript library commonly used to simplify working
+with the DOM and JavaScript in general.  It is the perfect tool to make
+web applications more dynamic by exchanging JSON between server and
+client.
+
+.. _jQuery: http://jquery.com/
+
+Loading jQuery
+--------------
+
+In order to use jQuery, you have to download it first and place it in the
+static folder of your application and then ensure it's loaded.  Ideally
+you have a layout template that is used for all pages where you just have
+to add two script statements to your `head` section.  One for jQuery, and
+one for your own script (called `app.js` here):
+
+.. sourcecode:: html
+
+   <script type=text/javascript src="{{
+       url_for('static', filename='jquery.js') }}"></script>
+   <script type=text/javascript src="{{
+       url_for('static', filename='app.js') }}"></script>
+
+Where is My Site?
+-----------------
+
+Do you know where your application is?  If you are developing the answer
+is quite simple: it's on localhost port something and directly on the root
+of that server.  But what if you later decide to move your application to
+a different location?  For example to ``http://example.com/myapp``?  On
+the server side this never was a problem because we were using the handy
+:func:`~flask.url_for` function that did could answer that question for
+us, but if we are using jQuery we should better not hardcode the path to
+the application but make that dynamic, so how can we do that?
+
+A simple method would be to add a script tag to our page that sets a
+global variable to the prefix to the root of the application.  Something
+like this:
+
+.. sourcecode:: html+jinja
+
+   <script type=text/javascript>
+     $SCRIPT_ROOT = {{ request.script_root|tojson|safe }};
+   </script>
+
+The ``|safe`` is necessary so that Jinja does not escape the JSON encoded
+string with HTML rules.  Usually this would be necessary, but we are
+inside a `script` block here where different rules apply.
+
+.. admonition:: Information for Pros
+
+   In HTML the `script` tag is declared `CDATA` which means that entities
+   will not be parsed.  Everything until ``</script>`` is handled as script.
+   This also means that there must never be any ``</`` between the script
+   tags.  ``|tojson`` is kindly enough to do the right thing here and
+   escape backslashes for you.

examples/jqueryexample/jqueryexample.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+"""
+    jQuery Example
+    ~~~~~~~~~~~~~~
+
+    A simple application that shows how Flask and jQuery get along.
+
+    :copyright: (c) 2010 by Armin Ronacher.
+    :license: BSD, see LICENSE for more details.
+"""
+from flask import Flask, jsonify, render_template, request
+app = Flask(__name__)
+
+
+@app.route('/_add_numbers')
+def add_numbers():
+    """Add two numbers server side, ridiculous but well..."""
+    a = request.args.get('a', 0, type=int)
+    b = request.args.get('b', 0, type=int)
+    return jsonify(result=a + b)
+
+
+@app.route('/')
+def index():
+    return render_template('index.html')
+
+
+if __name__ == '__main__':
+    app.run()

examples/jqueryexample/templates/index.html

@@ -0,0 +1,25 @@
+<!doctype html>
+<title>jQuery Example</title>
+<script type=text/javascript
+  src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
+<script type=text/javascript src="{{ url_for('static', filename='app.js')
+  }}"></script>
+<script type=text/javascript>
+  var $SCRIPT_ROOT = {{ request.script_root|tojson|safe }};
+
+  $(function() {
+    $('a#calculate').bind('click', function() {
+      $.getJSON($SCRIPT_ROOT + '/_add_numbers', {
+        a: $('input[name="a"]').val(),
+        b: $('input[name="b"]').val()
+      }, function(data) {
+        $("#result").text(data.result);
+      });
+    });
+  });
+</script>
+<h1>jQuery Example</h1>
+<p><input type=text size=5 name=a> +
+   <input type=text size=5 name=b> =
+   <span id=result>?</span>
+<p><a href=# id=calculate>calculate server side</a>

flask.py

@@ -15,11 +15,23 @@
 
 from jinja2 import Environment, PackageLoader, FileSystemLoader
 from werkzeug import Request as RequestBase, Response as ResponseBase, \
-     LocalStack, LocalProxy, create_environ, SharedDataMiddleware
+     LocalStack, LocalProxy, create_environ, SharedDataMiddleware, \
+     cached_property
 from werkzeug.routing import Map, Rule
 from werkzeug.exceptions import HTTPException
 from werkzeug.contrib.securecookie import SecureCookie
 
+# try to load the best simplejson implementation available.  If JSON
+# is not installed, we add a failing class.
+json_available = True
+try:
+    import simplejson as json
+except ImportError:
+    try:
+        import json
+    except ImportError:
+        json_available = False
+
 # utilities we import from Werkzeug and Jinja2 that are unused
 # in the module but are exported as public interface.
 from werkzeug import abort, redirect
@@ -49,6 +61,16 @@ def __init__(self, environ):
         self.endpoint = None
         self.view_args = None
 
+    @cached_property
+    def json(self):
+        """If the mimetype is `application/json` this will contain the
+        parsed JSON data.
+        """
+        if not json_available:
+            raise AttributeError('simplejson not available')
+        if self.mimetype == 'application/json':
+            return json.loads(self.data)
+
 
 class Response(ResponseBase):
     """The response object that is used by default in flask.  Works like the
@@ -81,7 +103,6 @@ def _fail(self, *args, **kwargs):
     del _fail
 
 
-
 class _RequestContext(object):
     """The request context contains all request relevant information.  It is
     created at the beginning of the request and pushed to the
@@ -133,6 +154,8 @@ def get_template_attribute(template_name, attribute):
         hello = get_template_attribute('_foo.html', 'hello')
         return hello('World')
 
+    .. versionadded:: 0.2
+
     :param template_name: the name of the template
     :param attribute: the name of the variable of macro to acccess
     """
@@ -162,6 +185,35 @@ def get_flashed_messages():
     return flashes
 
 
+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.
+
+    .. versionadded:: 0.2
+    """
+    return current_app.response_class(json.dumps(dict(*args, **kwargs),
+        indent=None if request.is_xhr else 2), mimetype='application/json')
+
+
 def render_template(template_name, **context):
     """Renders a template from the template folder with the given
     context.
@@ -326,6 +378,8 @@ def __init__(self, package_name):
             url_for=url_for,
             get_flashed_messages=get_flashed_messages
         )
+        if json_available:
+            self.jinja_env.filters['tojson'] = json.dumps
 
     def create_jinja_loader(self):
         """Creates the Jinja loader.  By default just a package loader for

tests/flask_tests.py

@@ -32,7 +32,7 @@ def meh():
             assert meh() == 'http://localhost/meh'
 
 
-class BasicFunctionality(unittest.TestCase):
+class BasicFunctionalityTestCase(unittest.TestCase):
 
     def test_request_dispatching(self):
         app = flask.Flask(__name__)
@@ -167,7 +167,35 @@ def test_static_files(self):
                 == '/static/index.html'
 
 
-class Templating(unittest.TestCase):
+class JSONTestCase(unittest.TestCase):
+
+    def test_jsonify(self):
+        d = dict(a=23, b=42, c=[1, 2, 3])
+        app = flask.Flask(__name__)
+        @app.route('/kw')
+        def return_kwargs():
+            return flask.jsonify(**d)
+        @app.route('/dict')
+        def return_dict():
+            return flask.jsonify(d)
+        c = app.test_client()
+        for url in '/kw', '/dict':
+            rv = c.get(url)
+            assert rv.mimetype == 'application/json'
+            assert flask.json.loads(rv.data) == d
+
+    def test_json_attr(self):
+        app = flask.Flask(__name__)
+        @app.route('/add', methods=['POST'])
+        def add():
+            return unicode(flask.request.json['a'] + flask.request.json['b'])
+        c = app.test_client()
+        rv = c.post('/add', data=flask.json.dumps({'a': 1, 'b': 2}),
+                            content_type='application/json')
+        assert rv.data == '3'
+
+
+class TemplatingTestCase(unittest.TestCase):
 
     def test_context_processing(self):
         app = flask.Flask(__name__)