JSONRPCServerMiddleware

Django and AJAX

This middleware is another attemp to simplify AJAX usage with Django based on JSON-RPC specification (​http://json-rpc.org/). It inspired by Java Struts2 JSON-plugin by Musachy Barroso (​http://cwiki.apache.org/S2PLUGINS/json-plugin.html) and SimpleJSONRPCServer by David McNab (​http://code.djangoproject.com/wiki/JSON-RPC).

Basic configuration

• jsonrpcserver.py must be on your PYTHONPATH.
• Put class 'jsonrpcserver.JSONRPCServerMiddleware' to Django middleware list in settings.py:

  MIDDLEWARE_CLASSES = (
      'django.middleware.common.CommonMiddleware',
      'django.contrib.sessions.middleware.SessionMiddleware',
      'django.contrib.auth.middleware.AuthenticationMiddleware',
      'django.middleware.transaction.TransactionMiddleware',
      "jsonrpcserver.JSONRPCServerMiddleware",
  )
  
  

• Add 'jsonrpc_urlpatterns' to 'urls.py' with 'urlpatterns' syntax:

  from django.conf.urls.defaults import *
  
  urlpatterns = patterns('',
  #standard django url configuration here
  #...
  )
  
  jsonrpc_urlpatterns = patterns('',
      (r'^myapp/json_rpc_service/$', 'myapp.newapp.json_rpc_views'),
      (r'^myapp/json_rpc_geoservice/$', 'myapp.geo.views'),
  )
  

note: 'myapp.newapp.json_rpc_views' IS NOT A FUNCTION, BUT A MODULE, that contains exposed JSON-RPC functions.

Optional Django settings

• JSONRPC_URLPATTERNS_NAME:

Default value: 'jsonrpc_urlpatterns'. Name of the variable in 'urls.py',that contains JSON-RPC URL patterns. URL pattern must have Django syntax, but they must contain MODULES NAMES, NOT FUNCTION NAMES as second element in tuple for patterns function.

• JSONRPC_SERIALIZER:

Default value: JSONSerializer class - thin wrapper over django.utils.simplejson. Name of the JSON serializer class, that must have methods 'serialize' and 'deserialize'

• JSONRPC_JSONFY_AT_ALL_COSTS:

Default value: False. Boolean flag, that determines whether JSON encoder should throwing an error or returning a str() representation of unsupportable python object. See implementation of AugmentedJSONEncoder class.

Usage

• Write exposed function im module, listed in jsonrpc_urlpatterns:

  from jsonrpcserver import jsonrpc_function
  @jsonrpc_function
  def my_python_method(par1, par2):
      return par1 + par2
      ...
  

• use from JS client (e.g. dojo):

  var  service = new dojo.rpc.JsonService({
      "serviceType": "JSON-RPC", 
      "serviceURL": "/myapp/json_rpc_service/"
  });
  service.callRemote("my_python_method", ["string1", "string2"])
      .addCallback(...);
  

Example

See example here: ​http://alx3apps.appspot.com/jsonrpc_example/.

Sources

Sources here: ​http://code.google.com/p/django-json-rpc-server/

Other

Written by alx3 (alx3apps(at)gmail(dot)com). You can use this code under the terms of BSD licence (like Django project).