# Protocol Buffers - Google's data interchange format
# Copyright 2008 Google Inc. All rights reserved.
# https://developers.google.com/protocol-buffers/
#
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"""Contains routines for printing protocol messages in JSON format.
Simple usage example:
# Create a proto object and serialize it to a json format string.
message = my_proto_pb2.MyMessage(foo='bar')
json_string = json_format.MessageToJson(message)
# Parse a json format string to proto object.
message = json_format.Parse(json_string, my_proto_pb2.MyMessage())
"""
__author__ = 'jieluo@google.com (Jie Luo)'
import base64
import json
import math
from six import text_type
import sys
from google.protobuf import descriptor
_TIMESTAMPFOMAT = '%Y-%m-%dT%H:%M:%S'
_INT_TYPES = frozenset([descriptor.FieldDescriptor.CPPTYPE_INT32,
descriptor.FieldDescriptor.CPPTYPE_UINT32,
descriptor.FieldDescriptor.CPPTYPE_INT64,
descriptor.FieldDescriptor.CPPTYPE_UINT64])
_INT64_TYPES = frozenset([descriptor.FieldDescriptor.CPPTYPE_INT64,
descriptor.FieldDescriptor.CPPTYPE_UINT64])
_FLOAT_TYPES = frozenset([descriptor.FieldDescriptor.CPPTYPE_FLOAT,
descriptor.FieldDescriptor.CPPTYPE_DOUBLE])
_INFINITY = 'Infinity'
_NEG_INFINITY = '-Infinity'
_NAN = 'NaN'
class Error(Exception):
"""Top-level module error for json_format."""
class SerializeToJsonError(Error):
"""Thrown if serialization to JSON fails."""
class ParseError(Error):
"""Thrown in case of parsing error."""
def MessageToJson(message, including_default_value_fields=False):
"""Converts protobuf message to JSON format.
Args:
message: The protocol buffers message instance to serialize.
including_default_value_fields: If True, singular primitive fields,
repeated fields, and map fields will always be serialized. If
False, only serialize non-empty fields. Singular message fields
and oneof fields are not affected by this option.
Returns:
A string containing the JSON formatted protocol buffer message.
"""
js = _MessageToJsonObject(message, including_default_value_fields)
return json.dumps(js, indent=2)
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()
if _IsWrapperMessage(message_descriptor):
return _WrapperMessageToJsonObject(message)
return _RegularMessageToJsonObject(message, including_default_value_fields)
def _IsMapEntry(field):
return (field.type == descriptor.FieldDescriptor.TYPE_MESSAGE and
field.message_type.has_options and
field.message_type.GetOptions().map_entry)
def _RegularMessageToJsonObject(message, including_default_value_fields):
"""Converts normal message according to Proto3 JSON Specification."""
js = {}
fields = message.ListFields()
include_default = including_default_value_fields
try:
for field, value in fields:
name = field.camelcase_name
if _IsMapEntry(field):
# Convert a map field.
v_field = field.message_type.fields_by_name['value']
js_map = {}
for key in value:
if isinstance(key, bool):
if key:
recorded_key = 'true'
else:
recorded_key = 'false'
else:
recorded_key = key
js_map[recorded_key] = _FieldToJsonObject(
v_field, value[key], including_default_value_fields)
js[name] = js_map
elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
# Convert a repeated field.
js[name] = [_FieldToJsonObject(field, k, include_default)
for k in value]
else:
js[name] = _FieldToJsonObject(field, value, include_default)
# Serialize default value if including_default_value_fields is True.
if including_default_value_fields:
message_descriptor = message.DESCRIPTOR
for field in message_descriptor.fields:
# Singular message fields and oneof fields will not be affected.
if ((field.label != descriptor.FieldDescriptor.LABEL_REPEATED and
field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE) or
field.containing_oneof):
continue
name = field.camelcase_name
if name in js:
# Skip the field which has been serailized already.
continue
if _IsMapEntry(field):
js[name] = {}
elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
js[name] = []
else:
js[name] = _FieldToJsonObject(field, field.default_value)
except ValueError as e:
raise SerializeToJsonError(
'Failed to serialize {0} field: {1}.'.format(field.name, e))
return js
def _FieldToJsonObject(
field, value, including_default_value_fields=False):
"""Converts field value according to Proto3 JSON Specification."""
if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
return _MessageToJsonObject(value, including_default_value_fields)
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_ENUM:
enum_value = field.enum_type.values_by_number.get(value, None)
if enum_value is not None:
return enum_value.name
else:
raise SerializeToJsonError('Enum field contains an integer value '
'which can not mapped to an enum value.')
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
# Use base64 Data encoding for bytes
return base64.b64encode(value).decode('utf-8')
else:
return value
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
return bool(value)
elif field.cpp_type in _INT64_TYPES:
return str(value)
elif field.cpp_type in _FLOAT_TYPES:
if math.isinf(value):
if value < 0.0:
return _NEG_INFINITY
else:
return _INFINITY
if math.isnan(value):
return _NAN
return value
def _IsWrapperMessage(message_descriptor):
return message_descriptor.file.name == 'google/protobuf/wrappers.proto'
def _WrapperMessageToJsonObject(message):
return _FieldToJsonObject(
message.DESCRIPTOR.fields_by_name['value'], message.value)
def _DuplicateChecker(js):
result = {}
for name, value in js:
if name in result:
raise ParseError('Failed to load JSON: duplicate key {0}.'.format(name))
result[name] = value
return result
def Parse(text, message):
"""Parses a JSON representation of a protocol message into a message.
Args:
text: Message JSON representation.
message: A protocol beffer message to merge into.
Returns:
The same message passed as argument.
Raises::
ParseError: On JSON parsing problems.
"""
if not isinstance(text, text_type): text = text.decode('utf-8')
try:
if sys.version_info < (2, 7):
# object_pair_hook is not supported before python2.7
js = json.loads(text)
else:
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)
return message
def _ConvertFieldValuePair(js, message):
"""Convert field value pairs into regular message.
Args:
js: A JSON object to convert the field value pairs.
message: A regular protocol message to record the data.
Raises:
ParseError: In case of problems converting.
"""
names = []
message_descriptor = message.DESCRIPTOR
for name in js:
try:
field = message_descriptor.fields_by_camelcase_name.get(name, None)
if not field:
raise ParseError(
'Message type "{0}" has no field named "{1}".'.format(
message_descriptor.full_name, name))
if name in names:
raise ParseError(
'Message type "{0}" should not have multiple "{1}" fields.'.format(
message.DESCRIPTOR.full_name, name))
names.append(name)
# Check no other oneof field is parsed.
if field.containing_oneof is not None:
oneof_name = field.containing_oneof.name
if oneof_name in names:
raise ParseError('Message type "{0}" should not have multiple "{1}" '
'oneof fields.'.format(
message.DESCRIPTOR.full_name, oneof_name))
names.append(oneof_name)
value = js[name]
if value is None:
message.ClearField(field.name)
continue
# Parse field value.
if _IsMapEntry(field):
message.ClearField(field.name)
_ConvertMapFieldValue(value, message, field)
elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
message.ClearField(field.name)
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:
sub_message = getattr(message, field.name).add()
_ConvertMessage(item, sub_message)
else:
getattr(message, field.name).append(
_ConvertScalarFieldValue(item, field))
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
sub_message = getattr(message, field.name)
_ConvertMessage(value, sub_message)
else:
setattr(message, field.name, _ConvertScalarFieldValue(value, field))
except ParseError as e:
if field and field.containing_oneof is None:
raise ParseError('Failed to parse {0} field: {1}'.format(name, e))
else:
raise ParseError(str(e))
except ValueError as e:
raise ParseError('Failed to parse {0} field: {1}.'.format(name, e))
except TypeError as e:
raise ParseError('Failed to parse {0} field: {1}.'.format(name, e))
def _ConvertMessage(value, message):
"""Convert a JSON object into a message.
Args:
value: A JSON object.
message: A WKT or regular protocol message to record the data.
Raises:
ParseError: In case of convert problems.
"""
message_descriptor = message.DESCRIPTOR
if hasattr(message, 'FromJsonString'):
message.FromJsonString(value)
elif _IsWrapperMessage(message_descriptor):
_ConvertWrapperMessage(value, message)
else:
_ConvertFieldValuePair(value, message)
def _ConvertWrapperMessage(value, message):
"""Convert a JSON representation into Wrapper message."""
field = message.DESCRIPTOR.fields_by_name['value']
setattr(message, 'value', _ConvertScalarFieldValue(value, field))
def _ConvertMapFieldValue(value, message, field):
"""Convert map field value for a message map field.
Args:
value: A JSON object to convert the map field value.
message: A protocol message to record the converted data.
field: The descriptor of the map field to be converted.
Raises:
ParseError: In case of convert problems.
"""
if not isinstance(value, dict):
raise ParseError(
'Map fieled {0} must be in {} 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:
key_value = _ConvertScalarFieldValue(key, key_field, True)
if value_field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
_ConvertMessage(value[key], getattr(message, field.name)[key_value])
else:
getattr(message, field.name)[key_value] = _ConvertScalarFieldValue(
value[key], value_field)
def _ConvertScalarFieldValue(value, field, require_str=False):
"""Convert a single scalar field value.
Args:
value: A scalar value to convert the scalar field value.
field: The descriptor of the field to convert.
require_str: If True, the field value must be a str.
Returns:
The converted scalar field value
Raises:
ParseError: In case of convert problems.
"""
if field.cpp_type in _INT_TYPES:
return _ConvertInteger(value)
elif field.cpp_type in _FLOAT_TYPES:
return _ConvertFloat(value)
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
return _ConvertBool(value, require_str)
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
return base64.b64decode(value)
else:
return value
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_ENUM:
# Convert an enum value.
enum_value = field.enum_type.values_by_name.get(value, None)
if enum_value is None:
raise ParseError(
'Enum value must be a string literal with double quotes. '
'Type "{0}" has no value named {1}.'.format(
field.enum_type.full_name, value))
return enum_value.number
def _ConvertInteger(value):
"""Convert an integer.
Args:
value: A scalar value to convert.
Returns:
The integer value.
Raises:
ParseError: If an integer couldn't be consumed.
"""
if isinstance(value, float):
raise ParseError('Couldn\'t parse integer: {0}.'.format(value))
if isinstance(value, text_type) and value.find(' ') != -1:
raise ParseError('Couldn\'t parse integer: "{0}".'.format(value))
return int(value)
def _ConvertFloat(value):
"""Convert an floating point number."""
if value == 'nan':
raise ParseError('Couldn\'t parse float "nan", use "NaN" instead.')
try:
# Assume Python compatible syntax.
return float(value)
except ValueError:
# Check alternative spellings.
if value == _NEG_INFINITY:
return float('-inf')
elif value == _INFINITY:
return float('inf')
elif value == _NAN:
return float('nan')
else:
raise ParseError('Couldn\'t parse float: {0}.'.format(value))
def _ConvertBool(value, require_str):
"""Convert a boolean value.
Args:
value: A scalar value to convert.
require_str: If True, value must be a str.
Returns:
The bool parsed.
Raises:
ParseError: If a boolean value couldn't be consumed.
"""
if require_str:
if value == 'true':
return True
elif value == 'false':
return False
else:
raise ParseError('Expected "true" or "false", not {0}.'.format(value))
if not isinstance(value, bool):
raise ParseError('Expected true or false without quotes.')
return value
