#

 #  Copyright (c) 2011 Edward Langley
 #  All rights reserved.

 #

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 #  modification, are permitted provided that the following conditions
 #  are met:

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 #  Redistributions of source code must retain the above copyright notice,
 #  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 copy

 import cookielib
 import urllib2

 import urlparse
 import itertools
 import traceback
 import random
 import time
 import UserDict, collections
 collections.Mapping.register(UserDict.DictMixin)
 
 from hashlib import sha1
 import jsonrpc.jsonutil

 from jsonrpc import __version__

 from jsonrpc.common import Response, Request

 
 __all__ = ['JSONRPCProxy', 'ProxyEvents']
 
 class NewStyleBaseException(Exception):
     def _get_message(self):
         return self._message
     def _set_message(self, message):
         self._message = message
 
     message = property(_get_message, _set_message)
 
 
 class IDGen(object):
 	def __init__(self):
 		self._hasher = sha1()
 		self._id = 0
 	def __get__(self, *_, **__):
 		self._id += 1
 		self._hasher.update(str(self._id))
 		self._hasher.update(time.ctime())
 		self._hasher.update(str(random.random))
 		return self._hasher.hexdigest()
 
 
 
 class ProxyEvents(object):
 	'''An event handler for JSONRPCProxy'''
 
 	#: an instance of a class which defines a __get__ method, used to generate a request id

 	IDGen = IDGen()

 
 
 	def __init__(self, proxy):
 		'''Allow a subclass to do its own initialization, gets any arguments leftover from __init__'''
 		self.proxy = proxy
 

 	def get_params(self, args, kwargs):

 		'''allow a subclass to modify the method's arguments
 
 		e.g. if an authentication token is necessary, the subclass can automatically insert it into every call'''
 		return args, kwargs
 
 	def proc_response(self, data):
 		'''allow a subclass to access the response data before it is returned to the user'''
 		return data
 

 
 class JSONRPCProcessor(urllib2.BaseHandler):
 	def __init__(self):
 		self.handler_order = 100
 
 	def http_request(self, request):
 		request.add_header('content-type', 'application/json')
 		request.add_header('user-agent', 'jsonrpc/'+__version__)
 		return request
 

 	https_request = http_request

 class JSONRPCProxy(object):
 	'''A class implementing a JSON-RPC Proxy.
 
 	:param str host: The HTTP server hosting the JSON-RPC server
 	:param str path: The path where the JSON-RPC server can be found
 
 	There are two ways of instantiating this class:
 	- JSONRPCProxy.from_url(url) -- give the absolute url to the JSON-RPC server
 	- JSONRPC(host, path) -- break up the url into smaller parts
 
 	'''
 
 	#: Override this attribute to customize proxy behavior
 	_eventhandler = ProxyEvents
 	def customize(self, eventhandler):
 		self._eventhandler = eventhandler(self)

 		return self

 
 	def _transformURL(self, serviceURL, path):

 		if serviceURL.endswith('/'):

 			serviceURL = serviceURL[:-1]

 		if path.endswith('/'):
 			path = path[:-1]
 		if path.startswith('/'):
 			path = path[1:]

 		return serviceURL, path
 
 
 	## Public interface
 	@classmethod
 	def from_url(cls, url, ctxid=None, serviceName=None):
 		'''Create a JSONRPCProxy from a URL'''
 		urlsp = urlparse.urlsplit(url)

 		url = '{0}://{1}'.format(urlsp.scheme, urlsp.netloc)

 		path = urlsp.path

 		if urlsp.query: path = '{0}?{1}'.format(path, urlsp.query)
 		if urlsp.fragment: path = '{0}#{1}'.format(path, urlsp.fragment)

 		return cls(url, path, serviceName, ctxid)
 
 

 	def __init__(self, host, path='jsonrpc', serviceName=None, *args, **kwargs):

 		self.serviceURL = host
 		self._serviceName = serviceName
 		self._path = path
 		self.serviceURL, self._path = self._transformURL(host, path)
 		self.customize(self._eventhandler)
 

 		cj = cookielib.CookieJar()
 		self._opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))

 		self._opener.add_handler(JSONRPCProcessor())

 
 	def _set_opener(self, opener):
 		self._opener  = opener
 		return self
 

 	def __getattr__(self, name):
 		if self._serviceName != None:

 			name = "{0}.{1}".format(self._serviceName, name)

 		return self.__class__(self.serviceURL, path=self._path, serviceName=name).customize(type(self._eventhandler))._set_opener(self._opener)

 	def _get_postdata(self, args=None, kwargs=None):

 		_args, _kwargs = self._eventhandler.get_params(args, kwargs)

 		id = self._eventhandler.IDGen

 		result = Request(id, self._serviceName, _args, _kwargs)

 		return jsonrpc.jsonutil.encode(result)

 	def _get_url(self):
 		result = [self.serviceURL]
 		if self._path:
 			result.append(self._path)

 		#result.append('')

 		return '/'.join(result)

 	def _post(self, url, data):
 		return self._opener.open(url, data)
 

 	def __call__(self, *args, **kwargs):
 

 		url = self._get_url()

 		postdata = self._get_postdata(args, kwargs)

 		#respdata = urllib2.urlopen(url, postdata).read()
 		respdata = self._post(url, postdata).read()

 		resp = Response.from_dict(jsonrpc.jsonutil.decode(respdata))
 		resp = self._eventhandler.proc_response(resp)

 		return resp.get_result()

 
 
 	def call(self, method, *args, **kwargs):
 		'''call a JSON-RPC method
 
 		It's better to use instance.<methodname>(\\*args, \\*\\*kwargs),
 		but this version might be useful occasionally
 		'''
 		p = self.__class__(self.serviceURL, path=self._path, serviceName=method)
 		return p(*args, **kwargs)
 
 
 	def batch_call(self, methods):
 		'''call several methods at once, return a list of (result, error) pairs
 
 		:param names: a dictionary { method: (args, kwargs) }
 		:returns: a list of pairs (result, error) where only one is not None
 		'''

 		result = None

 		if hasattr(methods, 'items'): methods = methods.items()
 		data = [ getattr(self, k)._get_postdata(*v) for k, v in methods ]

 		postdata = '{0}'.format(','.join(data))

 		respdata = self._post(self._get_url(), postdata).read()

 		resp = Response.from_json(respdata)
 		try:
 			result = resp.get_result()
 		except AttributeError:
 			result = [res.get_output() for res in resp]
 
 		return result