diff --git a/python/google/protobuf/internal/json_format_test.py b/python/google/protobuf/internal/json_format_test.py
index be3ad11..49e96a4 100644
--- a/python/google/protobuf/internal/json_format_test.py
+++ b/python/google/protobuf/internal/json_format_test.py
@@ -42,6 +42,12 @@
   import unittest2 as unittest
 except ImportError:
   import unittest
+from google.protobuf import any_pb2
+from google.protobuf import duration_pb2
+from google.protobuf import field_mask_pb2
+from google.protobuf import struct_pb2
+from google.protobuf import timestamp_pb2
+from google.protobuf import wrappers_pb2
 from google.protobuf.internal import well_known_types
 from google.protobuf import json_format
 from google.protobuf.util import json_format_proto3_pb2
@@ -326,6 +332,7 @@
     message.bytes_value.value = b''
     message.repeated_bool_value.add().value = True
     message.repeated_bool_value.add().value = False
+    message.repeated_int32_value.add()
     self.assertEqual(
         json.loads(json_format.MessageToJson(message, True)),
         json.loads('{\n'
@@ -334,7 +341,7 @@
                    '  "stringValue": "",'
                    '  "bytesValue": "",'
                    '  "repeatedBoolValue": [true, false],'
-                   '  "repeatedInt32Value": [],'
+                   '  "repeatedInt32Value": [0],'
                    '  "repeatedUint32Value": [],'
                    '  "repeatedFloatValue": [],'
                    '  "repeatedDoubleValue": [],'
@@ -346,11 +353,192 @@
     parsed_message = json_format_proto3_pb2.TestWrapper()
     self.CheckParseBack(message, parsed_message)
 
+  def testStructMessage(self):
+    message = json_format_proto3_pb2.TestStruct()
+    message.value['name'] = 'Jim'
+    message.value['age'] = 10
+    message.value['attend'] = True
+    message.value['email'] = None
+    message.value.get_or_create_struct('address')['city'] = 'SFO'
+    message.value['address']['house_number'] = 1024
+    struct_list = message.value.get_or_create_list('list')
+    struct_list.extend([6, 'seven', True, False, None])
+    struct_list.add_struct()['subkey2'] = 9
+    message.repeated_value.add()['age'] = 11
+    message.repeated_value.add()
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, False)),
+        json.loads(
+            '{'
+            '  "value": {'
+            '    "address": {'
+            '      "city": "SFO", '
+            '      "house_number": 1024'
+            '    }, '
+            '    "age": 10, '
+            '    "name": "Jim", '
+            '    "attend": true, '
+            '    "email": null, '
+            '    "list": [6, "seven", true, false, null, {"subkey2": 9}]'
+            '  },'
+            '  "repeatedValue": [{"age": 11}, {}]'
+            '}'))
+    parsed_message = json_format_proto3_pb2.TestStruct()
+    self.CheckParseBack(message, parsed_message)
+
+  def testValueMessage(self):
+    message = json_format_proto3_pb2.TestValue()
+    message.value.string_value = 'hello'
+    message.repeated_value.add().number_value = 11.1
+    message.repeated_value.add().bool_value = False
+    message.repeated_value.add().null_value = 0
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, False)),
+        json.loads(
+            '{'
+            '  "value": "hello",'
+            '  "repeatedValue": [11.1, false, null]'
+            '}'))
+    parsed_message = json_format_proto3_pb2.TestValue()
+    self.CheckParseBack(message, parsed_message)
+    # Can't parse back if the Value message is not set.
+    message.repeated_value.add()
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, False)),
+        json.loads(
+            '{'
+            '  "value": "hello",'
+            '  "repeatedValue": [11.1, false, null, null]'
+            '}'))
+
+  def testListValueMessage(self):
+    message = json_format_proto3_pb2.TestListValue()
+    message.value.values.add().number_value = 11.1
+    message.value.values.add().null_value = 0
+    message.value.values.add().bool_value = True
+    message.value.values.add().string_value = 'hello'
+    message.value.values.add().struct_value['name'] = 'Jim'
+    message.repeated_value.add().values.add().number_value = 1
+    message.repeated_value.add()
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, False)),
+        json.loads(
+            '{"value": [11.1, null, true, "hello", {"name": "Jim"}]\n,'
+            '"repeatedValue": [[1], []]}'))
+    parsed_message = json_format_proto3_pb2.TestListValue()
+    self.CheckParseBack(message, parsed_message)
+
+  def testAnyMessage(self):
+    message = json_format_proto3_pb2.TestAny()
+    value1 = json_format_proto3_pb2.MessageType()
+    value2 = json_format_proto3_pb2.MessageType()
+    value1.value = 1234
+    value2.value = 5678
+    message.value.Pack(value1)
+    message.repeated_value.add().Pack(value1)
+    message.repeated_value.add().Pack(value2)
+    message.repeated_value.add()
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "repeatedValue": [ {\n'
+            '    "@type": "type.googleapis.com/proto3.MessageType",\n'
+            '    "value": 1234\n'
+            '  }, {\n'
+            '    "@type": "type.googleapis.com/proto3.MessageType",\n'
+            '    "value": 5678\n'
+            '  },\n'
+            '  {}],\n'
+            '  "value": {\n'
+            '    "@type": "type.googleapis.com/proto3.MessageType",\n'
+            '    "value": 1234\n'
+            '  }\n'
+            '}\n'))
+    parsed_message = json_format_proto3_pb2.TestAny()
+    self.CheckParseBack(message, parsed_message)
+
+  def testWellKnownInAnyMessage(self):
+    message = any_pb2.Any()
+    int32_value = wrappers_pb2.Int32Value()
+    int32_value.value = 1234
+    message.Pack(int32_value)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": \"type.googleapis.com/google.protobuf.Int32Value\",\n'
+            '  "value": 1234\n'
+            '}\n'))
+    parsed_message = any_pb2.Any()
+    self.CheckParseBack(message, parsed_message)
+
+    timestamp = timestamp_pb2.Timestamp()
+    message.Pack(timestamp)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": "type.googleapis.com/google.protobuf.Timestamp",\n'
+            '  "value": "1970-01-01T00:00:00Z"\n'
+            '}\n'))
+    self.CheckParseBack(message, parsed_message)
+
+    duration = duration_pb2.Duration()
+    duration.seconds = 1
+    message.Pack(duration)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": "type.googleapis.com/google.protobuf.Duration",\n'
+            '  "value": "1s"\n'
+            '}\n'))
+    self.CheckParseBack(message, parsed_message)
+
+    field_mask = field_mask_pb2.FieldMask()
+    field_mask.paths.append('foo.bar')
+    field_mask.paths.append('bar')
+    message.Pack(field_mask)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": "type.googleapis.com/google.protobuf.FieldMask",\n'
+            '  "value": "foo.bar,bar"\n'
+            '}\n'))
+    self.CheckParseBack(message, parsed_message)
+
+    struct_message = struct_pb2.Struct()
+    struct_message['name'] = 'Jim'
+    message.Pack(struct_message)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": "type.googleapis.com/google.protobuf.Struct",\n'
+            '  "value": {"name": "Jim"}\n'
+            '}\n'))
+    self.CheckParseBack(message, parsed_message)
+
+    nested_any = any_pb2.Any()
+    int32_value.value = 5678
+    nested_any.Pack(int32_value)
+    message.Pack(nested_any)
+    self.assertEqual(
+        json.loads(json_format.MessageToJson(message, True)),
+        json.loads(
+            '{\n'
+            '  "@type": "type.googleapis.com/google.protobuf.Any",\n'
+            '  "value": {\n'
+            '    "@type": "type.googleapis.com/google.protobuf.Int32Value",\n'
+            '    "value": 5678\n'
+            '  }\n'
+            '}\n'))
+    self.CheckParseBack(message, parsed_message)
+
   def testParseNull(self):
     message = json_format_proto3_pb2.TestMessage()
-    message.repeated_int32_value.append(1)
-    message.repeated_int32_value.append(2)
-    message.repeated_int32_value.append(3)
     parsed_message = json_format_proto3_pb2.TestMessage()
     self.FillAllFields(parsed_message)
     json_format.Parse('{"int32Value": null, '
@@ -364,7 +552,7 @@
                       '"bytesValue": null,'
                       '"messageValue": null,'
                       '"enumValue": null,'
-                      '"repeatedInt32Value": [1, 2, null, 3],'
+                      '"repeatedInt32Value": null,'
                       '"repeatedInt64Value": null,'
                       '"repeatedUint32Value": null,'
                       '"repeatedUint64Value": null,'
@@ -378,6 +566,13 @@
                       '}',
                       parsed_message)
     self.assertEqual(message, parsed_message)
+    self.assertRaisesRegexp(
+        json_format.ParseError,
+        'Failed to parse repeatedInt32Value field: '
+        'null is not allowed to be used as an element in a repeated field.',
+        json_format.Parse,
+        '{"repeatedInt32Value":[1, null]}',
+        parsed_message)
 
   def testNanFloat(self):
     message = json_format_proto3_pb2.TestMessage()
@@ -529,6 +724,45 @@
         ' should not have multiple "oneof_value" oneof fields.',
         json_format.Parse, text, message)
 
+  def testInvalidListValue(self):
+    message = json_format_proto3_pb2.TestListValue()
+    text = '{"value": 1234}'
+    self.assertRaisesRegexp(
+        json_format.ParseError,
+        r'Failed to parse value field: ListValue must be in \[\] which is 1234',
+        json_format.Parse, text, message)
+
+  def testInvalidStruct(self):
+    message = json_format_proto3_pb2.TestStruct()
+    text = '{"value": 1234}'
+    self.assertRaisesRegexp(
+        json_format.ParseError,
+        'Failed to parse value field: Struct must be in a dict which is 1234',
+        json_format.Parse, text, message)
+
+  def testInvalidAny(self):
+    message = any_pb2.Any()
+    text = '{"@type": "type.googleapis.com/google.protobuf.Int32Value"}'
+    self.assertRaisesRegexp(
+        KeyError,
+        'value',
+        json_format.Parse, text, message)
+    text = '{"value": 1234}'
+    self.assertRaisesRegexp(
+        json_format.ParseError,
+        '@type is missing when parsing any message.',
+        json_format.Parse, text, message)
+    text = '{"@type": "type.googleapis.com/MessageNotExist", "value": 1234}'
+    self.assertRaisesRegexp(
+        TypeError,
+        'Can not find message descriptor by type_url: '
+        'type.googleapis.com/MessageNotExist.',
+        json_format.Parse, text, message)
+    # Only last part is to be used.
+    text = (r'{"@type": "incorrect.googleapis.com/google.protobuf.Int32Value",'
+            r'"value": 1234}')
+    json_format.Parse(text, message)
+
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/well_known_types.py b/python/google/protobuf/internal/well_known_types.py
index d3de983..d35fcc5 100644
--- a/python/google/protobuf/internal/well_known_types.py
+++ b/python/google/protobuf/internal/well_known_types.py
@@ -34,6 +34,7 @@
   - Any
   - Duration
   - FieldMask
+  - Struct
   - Timestamp
 """
 
@@ -41,6 +42,7 @@
 
 from datetime import datetime
 from datetime import timedelta
+import six
 
 from google.protobuf.descriptor import FieldDescriptor
 
@@ -64,9 +66,12 @@
 class Any(object):
   """Class for Any Message type."""
 
-  def Pack(self, msg):
+  def Pack(self, msg, type_url_prefix='type.googleapis.com/'):
     """Packs the specified message into current Any message."""
-    self.type_url = 'type.googleapis.com/%s' % msg.DESCRIPTOR.full_name
+    if len(type_url_prefix) < 1 or type_url_prefix[-1] != '/':
+      self.type_url = '%s/%s' % (type_url_prefix, msg.DESCRIPTOR.full_name)
+    else:
+      self.type_url = '%s%s' % (type_url_prefix, msg.DESCRIPTOR.full_name)
     self.value = msg.SerializeToString()
 
   def Unpack(self, msg):
@@ -614,9 +619,102 @@
     _AddFieldPaths(node[name], child_path, field_mask)
 
 
+_INT_OR_FLOAT = six.integer_types + (float,)
+
+
+def _SetStructValue(struct_value, value):
+  if value is None:
+    struct_value.null_value = 0
+  elif isinstance(value, bool):
+    # Note: this check must come before the number check because in Python
+    # True and False are also considered numbers.
+    struct_value.bool_value = value
+  elif isinstance(value, six.string_types):
+    struct_value.string_value = value
+  elif isinstance(value, _INT_OR_FLOAT):
+    struct_value.number_value = value
+  else:
+    raise ValueError('Unexpected type')
+
+
+def _GetStructValue(struct_value):
+  which = struct_value.WhichOneof('kind')
+  if which == 'struct_value':
+    return struct_value.struct_value
+  elif which == 'null_value':
+    return None
+  elif which == 'number_value':
+    return struct_value.number_value
+  elif which == 'string_value':
+    return struct_value.string_value
+  elif which == 'bool_value':
+    return struct_value.bool_value
+  elif which == 'list_value':
+    return struct_value.list_value
+  elif which is None:
+    raise ValueError('Value not set')
+
+
+class Struct(object):
+  """Class for Struct message type."""
+
+  __slots__ = []
+
+  def __getitem__(self, key):
+    return _GetStructValue(self.fields[key])
+
+  def __setitem__(self, key, value):
+    _SetStructValue(self.fields[key], value)
+
+  def get_or_create_list(self, key):
+    """Returns a list for this key, creating if it didn't exist already."""
+    return self.fields[key].list_value
+
+  def get_or_create_struct(self, key):
+    """Returns a struct for this key, creating if it didn't exist already."""
+    return self.fields[key].struct_value
+
+  # TODO(haberman): allow constructing/merging from dict.
+
+
+class ListValue(object):
+  """Class for ListValue message type."""
+
+  def __len__(self):
+    return len(self.values)
+
+  def append(self, value):
+    _SetStructValue(self.values.add(), value)
+
+  def extend(self, elem_seq):
+    for value in elem_seq:
+      self.append(value)
+
+  def __getitem__(self, index):
+    """Retrieves item by the specified index."""
+    return _GetStructValue(self.values.__getitem__(index))
+
+  def __setitem__(self, index, value):
+    _SetStructValue(self.values.__getitem__(index), value)
+
+  def items(self):
+    for i in range(len(self)):
+      yield self[i]
+
+  def add_struct(self):
+    """Appends and returns a struct value as the next value in the list."""
+    return self.values.add().struct_value
+
+  def add_list(self):
+    """Appends and returns a list value as the next value in the list."""
+    return self.values.add().list_value
+
+
 WKTBASES = {
     'google.protobuf.Any': Any,
     'google.protobuf.Duration': Duration,
     'google.protobuf.FieldMask': FieldMask,
+    'google.protobuf.ListValue': ListValue,
+    'google.protobuf.Struct': Struct,
     'google.protobuf.Timestamp': Timestamp,
 }
diff --git a/python/google/protobuf/internal/well_known_types_test.py b/python/google/protobuf/internal/well_known_types_test.py
index 0e31e6f..6acbee2 100644
--- a/python/google/protobuf/internal/well_known_types_test.py
+++ b/python/google/protobuf/internal/well_known_types_test.py
@@ -41,13 +41,17 @@
 except ImportError:
   import unittest
 
+from google.protobuf import any_pb2
 from google.protobuf import duration_pb2
 from google.protobuf import field_mask_pb2
+from google.protobuf import struct_pb2
 from google.protobuf import timestamp_pb2
 from google.protobuf import unittest_pb2
+from google.protobuf.internal import any_test_pb2
 from google.protobuf.internal import test_util
 from google.protobuf.internal import well_known_types
 from google.protobuf import descriptor
+from google.protobuf import text_format
 
 
 class TimeUtilTestBase(unittest.TestCase):
@@ -509,5 +513,124 @@
     self.assertEqual(1, len(nested_dst.payload.repeated_int32))
     self.assertEqual(1234, nested_dst.payload.repeated_int32[0])
 
+
+class StructTest(unittest.TestCase):
+
+  def testStruct(self):
+    struct = struct_pb2.Struct()
+    struct_class = struct.__class__
+
+    struct['key1'] = 5
+    struct['key2'] = 'abc'
+    struct['key3'] = True
+    struct.get_or_create_struct('key4')['subkey'] = 11.0
+    struct_list = struct.get_or_create_list('key5')
+    struct_list.extend([6, 'seven', True, False, None])
+    struct_list.add_struct()['subkey2'] = 9
+
+    self.assertTrue(isinstance(struct, well_known_types.Struct))
+    self.assertEquals(5, struct['key1'])
+    self.assertEquals('abc', struct['key2'])
+    self.assertIs(True, struct['key3'])
+    self.assertEquals(11, struct['key4']['subkey'])
+    inner_struct = struct_class()
+    inner_struct['subkey2'] = 9
+    self.assertEquals([6, 'seven', True, False, None, inner_struct],
+                      list(struct['key5'].items()))
+
+    serialized = struct.SerializeToString()
+
+    struct2 = struct_pb2.Struct()
+    struct2.ParseFromString(serialized)
+
+    self.assertEquals(struct, struct2)
+
+    self.assertTrue(isinstance(struct2, well_known_types.Struct))
+    self.assertEquals(5, struct2['key1'])
+    self.assertEquals('abc', struct2['key2'])
+    self.assertIs(True, struct2['key3'])
+    self.assertEquals(11, struct2['key4']['subkey'])
+    self.assertEquals([6, 'seven', True, False, None, inner_struct],
+                      list(struct2['key5'].items()))
+
+    struct_list = struct2['key5']
+    self.assertEquals(6, struct_list[0])
+    self.assertEquals('seven', struct_list[1])
+    self.assertEquals(True, struct_list[2])
+    self.assertEquals(False, struct_list[3])
+    self.assertEquals(None, struct_list[4])
+    self.assertEquals(inner_struct, struct_list[5])
+
+    struct_list[1] = 7
+    self.assertEquals(7, struct_list[1])
+
+    struct_list.add_list().extend([1, 'two', True, False, None])
+    self.assertEquals([1, 'two', True, False, None],
+                      list(struct_list[6].items()))
+
+    text_serialized = str(struct)
+    struct3 = struct_pb2.Struct()
+    text_format.Merge(text_serialized, struct3)
+    self.assertEquals(struct, struct3)
+
+    struct.get_or_create_struct('key3')['replace'] = 12
+    self.assertEquals(12, struct['key3']['replace'])
+
+
+class AnyTest(unittest.TestCase):
+
+  def testAnyMessage(self):
+    # Creates and sets message.
+    msg = any_test_pb2.TestAny()
+    msg_descriptor = msg.DESCRIPTOR
+    all_types = unittest_pb2.TestAllTypes()
+    all_descriptor = all_types.DESCRIPTOR
+    all_types.repeated_string.append(u'\u00fc\ua71f')
+    # Packs to Any.
+    msg.value.Pack(all_types)
+    self.assertEqual(msg.value.type_url,
+                     'type.googleapis.com/%s' % all_descriptor.full_name)
+    self.assertEqual(msg.value.value,
+                     all_types.SerializeToString())
+    # Tests Is() method.
+    self.assertTrue(msg.value.Is(all_descriptor))
+    self.assertFalse(msg.value.Is(msg_descriptor))
+    # Unpacks Any.
+    unpacked_message = unittest_pb2.TestAllTypes()
+    self.assertTrue(msg.value.Unpack(unpacked_message))
+    self.assertEqual(all_types, unpacked_message)
+    # Unpacks to different type.
+    self.assertFalse(msg.value.Unpack(msg))
+    # Only Any messages have Pack method.
+    try:
+      msg.Pack(all_types)
+    except AttributeError:
+      pass
+    else:
+      raise AttributeError('%s should not have Pack method.' %
+                           msg_descriptor.full_name)
+
+  def testPackWithCustomTypeUrl(self):
+    submessage = any_test_pb2.TestAny()
+    submessage.int_value = 12345
+    msg = any_pb2.Any()
+    # Pack with a custom type URL prefix.
+    msg.Pack(submessage, 'type.myservice.com')
+    self.assertEqual(msg.type_url,
+                     'type.myservice.com/%s' % submessage.DESCRIPTOR.full_name)
+    # Pack with a custom type URL prefix ending with '/'.
+    msg.Pack(submessage, 'type.myservice.com/')
+    self.assertEqual(msg.type_url,
+                     'type.myservice.com/%s' % submessage.DESCRIPTOR.full_name)
+    # Pack with an empty type URL prefix.
+    msg.Pack(submessage, '')
+    self.assertEqual(msg.type_url,
+                     '/%s' % submessage.DESCRIPTOR.full_name)
+    # Test unpacking the type.
+    unpacked_message = any_test_pb2.TestAny()
+    self.assertTrue(msg.Unpack(unpacked_message))
+    self.assertEqual(submessage, unpacked_message)
+
+
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/json_format.py b/python/google/protobuf/json_format.py
index cb76e11..23382bd 100644
--- a/python/google/protobuf/json_format.py
+++ b/python/google/protobuf/json_format.py
@@ -45,10 +45,11 @@
 import base64
 import json
 import math
-from six import text_type
+import six
 import sys
 
 from google.protobuf import descriptor
+from google.protobuf import symbol_database
 
 _TIMESTAMPFOMAT = '%Y-%m-%dT%H:%M:%S'
 _INT_TYPES = frozenset([descriptor.FieldDescriptor.CPPTYPE_INT32,
@@ -96,11 +97,15 @@
 def _MessageToJsonObject(message, including_default_value_fields):
   """Converts message to an object according to Proto3 JSON Specification."""
   message_descriptor = message.DESCRIPTOR
-  if hasattr(message, 'ToJsonString'):
-    return message.ToJsonString()
+  full_name = message_descriptor.full_name
   if _IsWrapperMessage(message_descriptor):
     return _WrapperMessageToJsonObject(message)
-  return _RegularMessageToJsonObject(message, including_default_value_fields)
+  if full_name in _WKTJSONMETHODS:
+    return _WKTJSONMETHODS[full_name][0](
+        message, including_default_value_fields)
+  js = {}
+  return _RegularMessageToJsonObject(
+      message, js, including_default_value_fields)
 
 
 def _IsMapEntry(field):
@@ -109,9 +114,8 @@
           field.message_type.GetOptions().map_entry)
 
 
-def _RegularMessageToJsonObject(message, including_default_value_fields):
+def _RegularMessageToJsonObject(message, js, including_default_value_fields):
   """Converts normal message according to Proto3 JSON Specification."""
-  js = {}
   fields = message.ListFields()
   include_default = including_default_value_fields
 
@@ -200,6 +204,79 @@
   return value
 
 
+def _AnyMessageToJsonObject(message, including_default):
+  """Converts Any message according to Proto3 JSON Specification."""
+  if not message.ListFields():
+    return {}
+  js = {}
+  type_url = message.type_url
+  js['@type'] = type_url
+  sub_message = _CreateMessageFromTypeUrl(type_url)
+  sub_message.ParseFromString(message.value)
+  message_descriptor = sub_message.DESCRIPTOR
+  full_name = message_descriptor.full_name
+  if _IsWrapperMessage(message_descriptor):
+    js['value'] = _WrapperMessageToJsonObject(sub_message)
+    return js
+  if full_name in _WKTJSONMETHODS:
+    js['value'] = _WKTJSONMETHODS[full_name][0](sub_message, including_default)
+    return js
+  return _RegularMessageToJsonObject(sub_message, js, including_default)
+
+
+def _CreateMessageFromTypeUrl(type_url):
+  # TODO(jieluo): Should add a way that users can register the type resolver
+  # instead of the default one.
+  db = symbol_database.Default()
+  type_name = type_url.split('/')[-1]
+  try:
+    message_descriptor = db.pool.FindMessageTypeByName(type_name)
+  except KeyError:
+    raise TypeError(
+        'Can not find message descriptor by type_url: {0}.'.format(type_url))
+  message_class = db.GetPrototype(message_descriptor)
+  return message_class()
+
+
+def _GenericMessageToJsonObject(message, unused_including_default):
+  """Converts message by ToJsonString according to Proto3 JSON Specification."""
+  # Duration, Timestamp and FieldMask have ToJsonString method to do the
+  # convert. Users can also call the method directly.
+  return message.ToJsonString()
+
+
+def _ValueMessageToJsonObject(message, unused_including_default=False):
+  """Converts Value message according to Proto3 JSON Specification."""
+  which = message.WhichOneof('kind')
+  # If the Value message is not set treat as null_value when serialize
+  # to JSON. The parse back result will be different from original message.
+  if which is None or which == 'null_value':
+    return None
+  if which == 'list_value':
+    return _ListValueMessageToJsonObject(message.list_value)
+  if which == 'struct_value':
+    value = message.struct_value
+  else:
+    value = getattr(message, which)
+  oneof_descriptor = message.DESCRIPTOR.fields_by_name[which]
+  return _FieldToJsonObject(oneof_descriptor, value)
+
+
+def _ListValueMessageToJsonObject(message, unused_including_default=False):
+  """Converts ListValue message according to Proto3 JSON Specification."""
+  return [_ValueMessageToJsonObject(value)
+          for value in message.values]
+
+
+def _StructMessageToJsonObject(message, unused_including_default=False):
+  """Converts Struct message according to Proto3 JSON Specification."""
+  fields = message.fields
+  js = {}
+  for key in fields.keys():
+    js[key] = _ValueMessageToJsonObject(fields[key])
+  return js
+
+
 def _IsWrapperMessage(message_descriptor):
   return message_descriptor.file.name == 'google/protobuf/wrappers.proto'
 
@@ -231,7 +308,7 @@
   Raises::
     ParseError: On JSON parsing problems.
   """
-  if not isinstance(text, text_type): text = text.decode('utf-8')
+  if not isinstance(text, six.text_type): text = text.decode('utf-8')
   try:
     if sys.version_info < (2, 7):
       # object_pair_hook is not supported before python2.7
@@ -240,7 +317,7 @@
       js = json.loads(text, object_pairs_hook=_DuplicateChecker)
   except ValueError as e:
     raise ParseError('Failed to load JSON: {0}.'.format(str(e)))
-  _ConvertFieldValuePair(js, message)
+  _ConvertMessage(js, message)
   return message
 
 
@@ -291,13 +368,22 @@
         if not isinstance(value, list):
           raise ParseError('repeated field {0} must be in [] which is '
                            '{1}.'.format(name, value))
-        for item in value:
-          if item is None:
-            continue
-          if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+        if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+          # Repeated message field.
+          for item in value:
             sub_message = getattr(message, field.name).add()
+            # None is a null_value in Value.
+            if (item is None and
+                sub_message.DESCRIPTOR.full_name != 'google.protobuf.Value'):
+              raise ParseError('null is not allowed to be used as an element'
+                               ' in a repeated field.')
             _ConvertMessage(item, sub_message)
-          else:
+        else:
+          # Repeated scalar field.
+          for item in value:
+            if item is None:
+              raise ParseError('null is not allowed to be used as an element'
+                               ' in a repeated field.')
             getattr(message, field.name).append(
                 _ConvertScalarFieldValue(item, field))
       elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
@@ -327,13 +413,87 @@
     ParseError: In case of convert problems.
   """
   message_descriptor = message.DESCRIPTOR
-  if hasattr(message, 'FromJsonString'):
-    message.FromJsonString(value)
-  elif _IsWrapperMessage(message_descriptor):
+  full_name = message_descriptor.full_name
+  if _IsWrapperMessage(message_descriptor):
     _ConvertWrapperMessage(value, message)
+  elif full_name in _WKTJSONMETHODS:
+    _WKTJSONMETHODS[full_name][1](value, message)
   else:
     _ConvertFieldValuePair(value, message)
 
+
+def _ConvertAnyMessage(value, message):
+  """Convert a JSON representation into Any message."""
+  if isinstance(value, dict) and not value:
+    return
+  try:
+    type_url = value['@type']
+  except KeyError:
+    raise ParseError('@type is missing when parsing any message.')
+
+  sub_message = _CreateMessageFromTypeUrl(type_url)
+  message_descriptor = sub_message.DESCRIPTOR
+  full_name = message_descriptor.full_name
+  if _IsWrapperMessage(message_descriptor):
+    _ConvertWrapperMessage(value['value'], sub_message)
+  elif full_name in _WKTJSONMETHODS:
+    _WKTJSONMETHODS[full_name][1](value['value'], sub_message)
+  else:
+    del value['@type']
+    _ConvertFieldValuePair(value, sub_message)
+  # Sets Any message
+  message.value = sub_message.SerializeToString()
+  message.type_url = type_url
+
+
+def _ConvertGenericMessage(value, message):
+  """Convert a JSON representation into message with FromJsonString."""
+  # Durantion, Timestamp, FieldMask have FromJsonString method to do the
+  # convert. Users can also call the method directly.
+  message.FromJsonString(value)
+
+
+_INT_OR_FLOAT = six.integer_types + (float,)
+
+
+def _ConvertValueMessage(value, message):
+  """Convert a JSON representation into Value message."""
+  if isinstance(value, dict):
+    _ConvertStructMessage(value, message.struct_value)
+  elif isinstance(value, list):
+    _ConvertListValueMessage(value, message.list_value)
+  elif value is None:
+    message.null_value = 0
+  elif isinstance(value, bool):
+    message.bool_value = value
+  elif isinstance(value, six.string_types):
+    message.string_value = value
+  elif isinstance(value, _INT_OR_FLOAT):
+    message.number_value = value
+  else:
+    raise ParseError('Unexpected type for Value message.')
+
+
+def _ConvertListValueMessage(value, message):
+  """Convert a JSON representation into ListValue message."""
+  if not isinstance(value, list):
+    raise ParseError(
+        'ListValue must be in [] which is {0}.'.format(value))
+  message.ClearField('values')
+  for item in value:
+    _ConvertValueMessage(item, message.values.add())
+
+
+def _ConvertStructMessage(value, message):
+  """Convert a JSON representation into Struct message."""
+  if not isinstance(value, dict):
+    raise ParseError(
+        'Struct must be in a dict which is {0}.'.format(value))
+  for key in value:
+    _ConvertValueMessage(value[key], message.fields[key])
+  return
+
+
 def _ConvertWrapperMessage(value, message):
   """Convert a JSON representation into Wrapper message."""
   field = message.DESCRIPTOR.fields_by_name['value']
@@ -353,7 +513,8 @@
   """
   if not isinstance(value, dict):
     raise ParseError(
-        'Map fieled {0} must be in {} which is {1}.'.format(field.name, value))
+        'Map field {0} must be in a dict which is {1}.'.format(
+            field.name, value))
   key_field = field.message_type.fields_by_name['key']
   value_field = field.message_type.fields_by_name['value']
   for key in value:
@@ -416,7 +577,7 @@
   if isinstance(value, float):
     raise ParseError('Couldn\'t parse integer: {0}.'.format(value))
 
-  if isinstance(value, text_type) and value.find(' ') != -1:
+  if isinstance(value, six.text_type) and value.find(' ') != -1:
     raise ParseError('Couldn\'t parse integer: "{0}".'.format(value))
 
   return int(value)
@@ -465,3 +626,20 @@
   if not isinstance(value, bool):
     raise ParseError('Expected true or false without quotes.')
   return value
+
+_WKTJSONMETHODS = {
+    'google.protobuf.Any': [_AnyMessageToJsonObject,
+                            _ConvertAnyMessage],
+    'google.protobuf.Duration': [_GenericMessageToJsonObject,
+                                 _ConvertGenericMessage],
+    'google.protobuf.FieldMask': [_GenericMessageToJsonObject,
+                                  _ConvertGenericMessage],
+    'google.protobuf.ListValue': [_ListValueMessageToJsonObject,
+                                  _ConvertListValueMessage],
+    'google.protobuf.Struct': [_StructMessageToJsonObject,
+                               _ConvertStructMessage],
+    'google.protobuf.Timestamp': [_GenericMessageToJsonObject,
+                                  _ConvertGenericMessage],
+    'google.protobuf.Value': [_ValueMessageToJsonObject,
+                              _ConvertValueMessage]
+}