Package: extdirect
============Introduction============To use this package, you must either have simplejson installed, or be usingPython 2.6 (which includes simplejson as the json package).ExtJS 3.0 provides Ext.Direct, an extremely simple way to remote server-sidemethods to the client side. extdirect provides a Python implementationof a server-side Ext.Direct router, which can accept and parse Ext.Directrequest data, route it to the correct method, and create, encode and return theproper data structure wrapping the results. extdirect also provides aclass that can generate the client-side JavaScript defining an Ext.Directprovider from a router class.For a full description of Ext.Direct's features, see:http://www.extjs.com/products/extjs/direct.phpLet's see how the server side works. First, we'll define a router:>>> from extdirect.router import DirectRouter>>> class TestUtils(DirectRouter):......     def capitalize(self, word):...         return word.upper()......     def today(self):...         return "Today is Wednesday."We've defined two methods we want remoted to the client.Although we don't have a real client in this test runner, here's how one wouldgenerate the code that needs to be given to the client defining the provider.Ignoring actual implementation, which would depend on the framework being used,let's say we'll have this class available at URL '/utils', and we want ourclient-side namespace containing these methods simply to be called 'Remote.'>>> from extdirect.router import DirectProviderDefinition>>> print DirectProviderDefinition(TestUtils, '/utils', 'Remote').render()... #doctest: +NORMALIZE_WHITESPACE<script type="text/javascript">Ext.Direct.addProvider({"url": "/utils","namespace": "Remote","type": "remoting","id": "TestUtils","actions": {"TestUtils": [{"name": "capitalize", "len": 1},{"name": "today", "len": 1}]}});</script>Now, assuming that, one way or another, we've provided this code to the clientand our class is available at that URL, we are now able to access these methodsfrom the browser:Remote.TestUtils.capitalize({word:'foo'}, console.log)That example would make a call to the 'capitalize' method on our TestUtilsclass and feed the result to our callback, which in this case merely prints theresult to the JS console.Let's see how that would work from the perspective of the server. That callwould make a POST request with a JSON-encoded body, so let's create thatmanually:>>> from extdirect.router import json>>> data = {"action":"TestUtils","method":"capitalize","data":[{"word":"foo"}],"type":"rpc","tid":1}>>> body = json.dumps(data)Our class name is passed in as "action", the method name as "method", andwhatever data we sent as a single-member array containing a hash of ourparameters. For our purposes, "type" will always be "rpc". Ext.Direct requestsalso provide a transaction id ("tid") which may be used as you see fit tohandle the possibility of stale data.Now, let's make an instance of our server-side class:>>> utils = TestUtils()This instance is callable and accepts the request body, and returns aJSON-encoded object exhibiting the structure expected by Ext.Direct on theclient:>>> utils(body)'{"tid": 1, "action": "TestUtils", "type": "rpc", "method": "capitalize", "result": "FOO"}'Notice the "result", which is what we'd expect. The client would decode thisobject and pass the "result" value to the callback. Just for fun, let's checkout our other defined method:>>> data = {"action":"TestUtils","method":"today","data":[],"type":"rpc","tid":1}>>> body = json.dumps(data)>>> resultob = json.loads(utils(body))>>> print resultob['result']Today is Wednesday.===========Zope Router===========Using extdirect in Zope is extremely simple, due to a custom ZCMLdirective that registers both a BrowserView for the server-side API and aviewlet to deliver the provider definition to the client.1. Define your classe.g., in myapi.py:from extdirect.zope import DirectRouterclass MyApi(DirectRouter):def a_method(self):return 'A Value'2. Register the class as a direct router<configure xmlns="http://namespaces.zope.org/browser"><include package="extdirect.zope" file="meta.zcml"/><directRoutername="myapi"namespace="MyApp.remote"class=".myapi.MyApi"/></configure>3. Provide the extdirect viewletManager in your template.(Note: Ext is a prerequisite.)<tal:block tal:content="structure provider:extdirect"/>4. Call methods at will!<script>function a_method_callback(result){... do something with result ...}MyApp.remote.a_method({}, a_method_callback);</script>=============Django Router=============So, you have a Django app, and you want to add Ext.Direct. Here's how:1. Add 'extdirect.django' to INSTALLED_APPS in settings.py2. In a new file called direct.py, define your router class and register it:from extdirect.django import DirectRouter, register_routerclass MyRouter(DirectRouter):def uppercase(self, word):return word.upper()def lowercase(self, word):return word.lower()register_router(MyRouter, 'Remote')The arguments to register_router are the router class, the client-sidenamespace, and an optional url under /extdirect at which the routershould be available (defaults to the name of the class).3. In the root URLconf, map the extdirect urls by adding:(r'^extdirect/', include('extdirect.django.urls'))4. Also in the root URLconf, add these two lines:import extdirect.django as extdirectextdirect.autodiscover()5. In your template, load the provider definitions:{% load direct_providers %}{% direct_providers %}6. That's it. You should now have access on that template to the remotemethods:Remote.MyRouter.uppercase({word:'a word'}, callback);0.4Removed stripped-down direct.js for licensing reasonsRereleased under BSD licenseAdded request batching support (thanks to Brian Edwards, bedwards@zenoss.com)Added provided timeout option in Zope (thanks to Jon-Pierre Gentil,jgentil@zenoss.com)0.3Updated django subpackage with Avizoa's patch replacing "import views" with themuch cleaner "extdirect.autodiscover()".0.2Added django subpackage0.1Initial release, including zope subpackage