# $Id: server.py,v 1.8 2011/05/26 19:34:19 edwlan Exp $
 
 #  
 #  Copyright (c) 2011 Edward Langley
 #  All rights reserved.
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 #  this list of conditions and the following disclaimer.
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 #  Redistributions in binary form must reproduce the above copyright
 #  notice, this list of conditions and the following disclaimer in the
 #  documentation and/or other materials provided with the distribution.
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 #  Neither the name of the project's author nor the names of its
 #  contributors may be used to endorse or promote products derived from
 #  this software without specific prior written permission.
 #  
 #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 #  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 #  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 #  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 #  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 #  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 #  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 #
 import cgi
 import time
 import jsonrpc.jsonutil
 
 # Twisted imports
 from twisted.web import server
 from twisted.internet import threads
 from twisted.web.resource import Resource
 
 
 import UserDict, collections
 collections.Mapping.register(UserDict.DictMixin)
 
 class ServerEvents(object):
 	'''Subclass this and pass to :py:meth:`jsonrpc.customize` to customize the jsonrpc server'''
 
 	def __init__(self, jsonrpc):
 		#: A link to the JSON-RPC server instance
 		self.server = jsonrpc
 
 	def callmethod(self, request, method, kwargs, args, **kw):
 		'''Override to implement the methods the server will make available'''
 		return 'Test Result'
 
 	def processrequest(self, result, args):
 		'''Override to implement custom handling of the method result and request'''
 		return result
 
 	def logerror(self, result, request):
 		'''Override to implement custom error handling'''
 		pass
 
 
 
 
 ## Base class providing a JSON-RPC 2.0 implementation with 2 customizable hooks
 class JSON_RPC(Resource):
 	'''This class implements a JSON-RPC 2.0 server as a Twisted Resource'''
 	isLeaf = True
 
 	#: set by :py:meth:`customize` used to change the behavior of the server
 	eventhandler = ServerEvents
 
 	def customize(self, eventhandler):
 		'''customize the behavior of the server'''
 		self.eventhandler = eventhandler(self)
 		return self
 
 
 	def __init__(self, *args, **kwargs):
 		self.customize(self.eventhandler)
 		Resource.__init__(self,*args, **kwargs)
 
 	def _parse_data(self, content):
 		if content.get('jsonrpc') != '2.0': raise ValueError, 'wrong JSON-RPC version'
 		method = content.get('method')
 		kwargs = content.get('params', {})
 		args = ()
 		if not isinstance(kwargs, dict):
 			args = tuple(kwargs)
 			kwargs = {}
 		else:
 			args = kwargs.pop('__args', args)
 		kwargs = dict( (str(k), v) for k,v in kwargs.items() )
 		return method, kwargs, args
 
 
 	def _cbRender(self, result, request):
 		request.setHeader("content-type", 'application/json')
 		request.setResponseCode(200)
 		result = jsonrpc.jsonutil.encode(result).encode('utf-8')
 		request.setHeader("content-length", len(result))
 		request.write(result)
 		request.finish()
 
 
 	def _ebRender(self, result, request, content, *args, **kwargs):
 		result_template = dict(
 			jsonrpc='2.0',
 			error= dict(
 				code=0,
 				message='Stub Message',
 				data = 'Stub Data'
 		))
 
 		try:
 			request.setHeader("X-Error", result.getErrorMessage())
 			result_template['error'].update(
 					code=0,
 					message=' '.join(str(x) for x in result.value),
 					data=content
 			)
 			if isinstance(content, list):
 				result_template['id'] = content[0].get('id', '<NULL>')
 				result_template = [result]
 			else: result_template['id'] = content.get('id')
 		except Exception, e:
 			result_template['error'].update(
 				code = 0,
 				message = 'Error in errorpage: %s' % e,
 				data = ''
 			)
 
 		result = result_template
 		result['error']['message'] = cgi.escape(result['error']['message'])
 		result = jsonrpc.jsonutil.encode(result)
 		result = result.encode('utf-8')
 		request.setHeader("content-length", len(result))
 		request.setResponseCode(500)
 		self.eventhandler.logerror(result, request)
 		request.write(result)
 		request.finish()
 
 
 	def render(self, request):
 		ctxid = request.getCookie("ctxid") or request.args.get("ctxid", [None])[0]
 		host = request.getClientIP()
 
 		request.content.seek(0, 0)
 		content = jsonrpc.jsonutil.decode(request.content.read())
 		d = threads.deferToThread(self._action, request, content, ctxid=ctxid, host=host)
 		d.addCallback(self._cbRender, request)
 		d.addErrback(self._ebRender, request, content)
 		return server.NOT_DONE_YET
 
 
 	def _action(self, request, contents, **kw):
 		result = []
 		ol = (True if isinstance(contents, list) else False)
 		if not ol:
 			contents = [contents]
 
 		for content in contents:
 			res = dict(
 				jsonrpc = '2.0',
 				id = content.get('id'),
 				result = self.eventhandler.callmethod(request, *self._parse_data(content), **kw)
 			)
 
 			res = self.eventhandler.processrequest(res, request.args)
 
 			result.append(res)
 
 
 		return ( result if ol else result[0] )
 
 
 
 __version__ = "$Revision: 1.8 $".split(":")[1][:-1].strip()