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# $Id: server.py,v 1.8 2011/05/26 19:34:19 edwlan Exp $
#
# Copyright (c) 2011 Edward Langley
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 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.
#
# 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,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
# TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#
import cgi
import copy
import time
import itertools
import jsonrpc.jsonutil
import json
# 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):
'''Finds the method and calls it with the specified args'''
method = self.findmethod(method)
if method is None: raise MethodNotFound
return method(*args, **kwargs)
def findmethod(self, method):
'''Override to allow server to define methods'''
return lambda *a, **kw: 'Test Data'
def processrequest(self, result, args):
'''Override to implement custom handling of the method result and request'''
return result
def log(self, result, request):
'''Override to implement custom error handling'''
pass
def processcontent(self, content, request):
'''Given the freshly decoded content of the request, return what content should be used'''
return content
class ServerError(Exception):
code = 0
msg = ""
id = None
def json_equivalent(self):
return dict(jsonrpc="2.0", error=dict(code=self.code, message=self.msg), id=self.id)
def __str__(self):
return jsonrpc.jsonutil.encode(self)
class InvalidRequest(ServerError):
code = -32600
msg = "Invalid Request."
class MethodNotFound(ServerError):
code = -32601
msg = "Procedure not found."
class ParseError(ServerError):
code = -32700
msg = "Parse error."
## 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 render(self, request):
#move to emen2 event handler
#ctxid = request.getCookie("ctxid") or request.args.get("ctxid", [None])[0]
#host = request.getClientIP()
request.content.seek(0, 0)
try:
try:
content = jsonrpc.jsonutil.decode(request.content.read())
except ValueError: raise ParseError
content = self.eventhandler.processcontent(content, request)
d = threads.deferToThread(self._action, request, content)
d.addCallback(self._cbRender, request)
d.addErrback(self._ebRender, request, content.get('id') if hasattr(content, 'get') else None)
except BaseException, e:
self._ebRender(e, request, None)
return server.NOT_DONE_YET
def _cbRender(self, result, request):
if result is not None:
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, id, finish=True):
self.eventhandler.log(result, request)
err = None
if not isinstance(result, BaseException):
try: result.raiseException()
except BaseException, e:
err = e
else: err = result
err = self.render_error(err, id)
request.setHeader("content-type", 'application/json')
request.setResponseCode(200)
result = jsonrpc.jsonutil.encode(err).encode('utf-8')
request.setHeader("content-length", len(result))
request.write(result)
if finish: request.finish()
def _parse_data(self, content):
if content.get('jsonrpc') != '2.0': raise InvalidRequest
method = content.get('method')
if not isinstance(method, (str, unicode)): raise InvalidRequest
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 render_error(self, e, id):
if isinstance(e, ServerError):
e.id = id
err = e.json_equivalent()
else:
err = dict(
jsonrpc='2.0',
id = id,
error= dict(
code=0,
message=str(e),
data = e.args
))
return err
def _action(self, request, contents):
result = []
ol = (True if isinstance(contents, list) else False)
if not ol: contents = [contents]
if contents == []: raise InvalidRequest
for content in contents:
try:
res = dict(jsonrpc='2.0', id=content.get('id'), result=self.eventhandler.callmethod(request, *self._parse_data(content)))
res = self.eventhandler.processrequest(res, request.args)
if res['id'] is not None: result.append(res)
except Exception, e:
err = self.render_error(e, content.get('id'))
if err['id'] is not None: result.append(err)
self.eventhandler.log(result, request)
if result != []:
if not ol: result = result[0]
else: result = None
return result
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