# Copyright 2014 The Chromium Authors. All rights reserved. # Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. """Module to implement the SimpleXMLRPCServer module using JSON-RPC. This module uses SimpleXMLRPCServer as the base and only overrides those portions that implement the XML-RPC protocol. These portions are rewritten to use the JSON-RPC protocol instead. When large portions of code need to be rewritten the original code and comments are preserved. The intention here is to keep the amount of code change to a minimum. This module only depends on default Python modules, as well as jsonrpclib which also uses only default modules. No third party code is required to use this module. """ import json import SimpleXMLRPCServer as _base import SocketServer import sys import traceback try: import fcntl except ImportError: fcntl = None try: import gzip except ImportError: gzip = None #python can be built without zlib/gzip support #pylint: disable=relative-import import jsonrpclib class SimpleJSONRPCRequestHandler(_base.SimpleXMLRPCRequestHandler): """Request handler class for received requests. This class extends the functionality of SimpleXMLRPCRequestHandler and only overrides the operations needed to change the protocol from XML-RPC to JSON-RPC. """ def do_POST(self): """Handles the HTTP POST request. Attempts to interpret all HTTP POST requests as JSON-RPC calls, which are forwarded to the server's _dispatch method for handling. """ # Check that the path is legal if not self.is_rpc_path_valid(): self.report_404() return try: # Get arguments by reading body of request. # We read this in chunks to avoid straining # socket.read(); around the 10 or 15Mb mark, some platforms # begin to have problems (bug #792570). max_chunk_size = 10*1024*1024 size_remaining = int(self.headers['content-length']) data = [] while size_remaining: chunk_size = min(size_remaining, max_chunk_size) chunk = self.rfile.read(chunk_size) if not chunk: break data.append(chunk) size_remaining -= len(data[-1]) data = ''.join(data) data = self.decode_request_content(data) if data is None: return # response has been sent # In previous versions of SimpleXMLRPCServer, _dispatch # could be overridden in this class, instead of in # SimpleXMLRPCDispatcher. To maintain backwards compatibility, # check to see if a subclass implements _dispatch and dispatch # using that method if present. response = self.server._marshaled_dispatch( data, getattr(self, '_dispatch', None), self.path) except Exception, e: # This should only happen if the module is buggy # internal error, report as HTTP server error self.send_response(500) # Send information about the exception if requested if (hasattr(self.server, '_send_traceback_header') and self.server._send_traceback_header): self.send_header('X-exception', str(e)) self.send_header('X-traceback', traceback.format_exc()) self.send_header('Content-length', '0') self.end_headers() else: # got a valid JSON RPC response self.send_response(200) self.send_header('Content-type', 'application/json') if self.encode_threshold is not None: if len(response) > self.encode_threshold: q = self.accept_encodings().get('gzip', 0) if q: try: response = jsonrpclib.gzip_encode(response) self.send_header('Content-Encoding', 'gzip') except NotImplementedError: pass self.send_header('Content-length', str(len(response))) self.end_headers() self.wfile.write(response) class SimpleJSONRPCDispatcher(_base.SimpleXMLRPCDispatcher): """Dispatcher for received JSON-RPC requests. This class extends the functionality of SimpleXMLRPCDispatcher and only overrides the operations needed to change the protocol from XML-RPC to JSON-RPC. """ def _marshaled_dispatch(self, data, dispatch_method=None, path=None): """Dispatches an JSON-RPC method from marshalled (JSON) data. JSON-RPC methods are dispatched from the marshalled (JSON) data using the _dispatch method and the result is returned as marshalled data. For backwards compatibility, a dispatch function can be provided as an argument (see comment in SimpleJSONRPCRequestHandler.do_POST) but overriding the existing method through subclassing is the preferred means of changing method dispatch behavior. Returns: The JSON-RPC string to return. """ method = '' params = [] ident = '' try: request = json.loads(data) jsonrpclib.ValidateRequest(request) method = request['method'] params = request['params'] ident = request['id'] # generate response if dispatch_method is not None: response = dispatch_method(method, params) else: response = self._dispatch(method, params) response = jsonrpclib.CreateResponseString(response, ident) except jsonrpclib.Fault as fault: response = jsonrpclib.CreateResponseString(fault, ident) # Catch all exceptions here as they should be raised on the caller side. except: #pylint: disable=bare-except # report exception back to server exc_type, exc_value, _ = sys.exc_info() response = jsonrpclib.CreateResponseString( jsonrpclib.Fault(1, '%s:%s' % (exc_type, exc_value)), ident) return response class SimpleJSONRPCServer(SocketServer.TCPServer, SimpleJSONRPCDispatcher): """Simple JSON-RPC server. This class mimics the functionality of SimpleXMLRPCServer and only overrides the operations needed to change the protocol from XML-RPC to JSON-RPC. """ allow_reuse_address = True # Warning: this is for debugging purposes only! Never set this to True in # production code, as will be sending out sensitive information (exception # and stack trace details) when exceptions are raised inside # SimpleJSONRPCRequestHandler.do_POST _send_traceback_header = False def __init__(self, addr, requestHandler=SimpleJSONRPCRequestHandler, logRequests=True, allow_none=False, encoding=None, bind_and_activate=True): self.logRequests = logRequests SimpleJSONRPCDispatcher.__init__(self, allow_none, encoding) SocketServer.TCPServer.__init__(self, addr, requestHandler, bind_and_activate) # [Bug #1222790] If possible, set close-on-exec flag; if a # method spawns a subprocess, the subprocess shouldn't have # the listening socket open. if fcntl is not None and hasattr(fcntl, 'FD_CLOEXEC'): flags = fcntl.fcntl(self.fileno(), fcntl.F_GETFD) flags |= fcntl.FD_CLOEXEC fcntl.fcntl(self.fileno(), fcntl.F_SETFD, flags)