Adding the first set of remote test cases and associated framework.

remoting/tools/remote_test_helper/SimpleJSONRPCServer.py

+# Copyright (c) 2014 The Chromium Authors. All rights reserved.

[Jamie, 2014/12/17 03:15:41]

Nit: No need for (c), here and below.

[Mike Meade, 2014/12/18 18:54:25]

Done.

+# 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 fcntl
+import json
+import SimpleXMLRPCServer as _base
+import SocketServer
+import sys
+import traceback
+import jsonrpclib
+try:
+  import gzip
+except ImportError:
+  gzip = None #python can be built without zlib/gzip support
+
+
+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)
+      print 'request:', request
+      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)
+
+    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)
+    print 'response:', response
+    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)