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#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""Describe ProtoRPC Messages in JSON Schema.
Add protorpc.message subclasses to MessageTypeToJsonSchema and get a JSON
Schema description of all the messages.
"""
import re
from protorpc import message_types
from protorpc import messages
__all__ = ['MessageTypeToJsonSchema']
class MessageTypeToJsonSchema(object):
"""Describe ProtoRPC messages in JSON Schema.
Add protorpc.message subclasses to MessageTypeToJsonSchema and get a JSON
Schema description of all the messages. MessageTypeToJsonSchema handles
all the types of fields that can appear in a message.
"""
__FIELD_TO_SCHEMA_TYPE_MAP = {
messages.IntegerField: {messages.Variant.INT32: ('integer', 'int32'),
messages.Variant.INT64: ('string', 'int64'),
messages.Variant.UINT32: ('integer', 'uint32'),
messages.Variant.UINT64: ('string', 'uint64'),
messages.Variant.SINT32: ('integer', 'int32'),
messages.Variant.SINT64: ('string', 'int64'),
None: ('integer', 'int64')},
messages.FloatField: {messages.Variant.FLOAT: ('number', 'float'),
messages.Variant.DOUBLE: ('number', 'double'),
None: ('number', 'float')},
messages.BooleanField: ('boolean', None),
messages.BytesField: ('string', 'byte'),
message_types.DateTimeField: ('string', 'date-time'),
messages.StringField: ('string', None),
messages.MessageField: ('object', None),
messages.EnumField: ('string', None),
}
__DEFAULT_SCHEMA_TYPE = ('string', None)
def __init__(self):
self.__schemas = {}
self.__normalized_names = {}
def add_message(self, message_type):
"""Add a new message.
Args:
message_type: protorpc.message.Message class to be parsed.
Returns:
string, The JSON Schema id.
Raises:
KeyError if the Schema id for this message_type would collide with the
Schema id of a different message_type that was already added.
"""
name = self.__normalized_name(message_type)
if name not in self.__schemas:
self.__schemas[name] = None
schema = self.__message_to_schema(message_type)
self.__schemas[name] = schema
return name
def ref_for_message_type(self, message_type):
"""Returns the JSON Schema id for the given message.
Args:
message_type: protorpc.message.Message class to be parsed.
Returns:
string, The JSON Schema id.
Raises:
KeyError: if the message hasn't been parsed via add_message().
"""
name = self.__normalized_name(message_type)
if name not in self.__schemas:
raise KeyError('Message has not been parsed: %s', name)
return name
def schemas(self):
"""Returns the JSON Schema of all the messages.
Returns:
object: JSON Schema description of all messages.
"""
return self.__schemas.copy()
def __normalized_name(self, message_type):
"""Normalized schema name.
Generate a normalized schema name, taking the class name and stripping out
everything but alphanumerics, and camel casing the remaining words.
A normalized schema name is a name that matches [a-zA-Z][a-zA-Z0-9]*
Args:
message_type: protorpc.message.Message class being parsed.
Returns:
A string, the normalized schema name.
Raises:
KeyError if a collision is found between normalized names.
"""
name = message_type.definition_name()
split_name = re.split(r'[^0-9a-zA-Z]', name)
normalized = ''.join(
part[0].upper() + part[1:] for part in split_name if part)
previous = self.__normalized_names.get(normalized)
if previous:
if previous != name:
raise KeyError('Both %s and %s normalize to the same schema name: %s' %
(name, previous, normalized))
else:
self.__normalized_names[normalized] = name
return normalized
def __message_to_schema(self, message_type):
"""Parse a single message into JSON Schema.
Will recursively descend the message structure
and also parse other messages references via MessageFields.
Args:
message_type: protorpc.messages.Message class to parse.
Returns:
An object representation of the schema.
"""
name = self.__normalized_name(message_type)
schema = {
'id': name,
'type': 'object',
}
if message_type.__doc__:
schema['description'] = message_type.__doc__
properties = {}
for field in message_type.all_fields():
descriptor = {}
type_info = {}
if type(field) == messages.MessageField:
field_type = field.type().__class__
type_info['$ref'] = self.add_message(field_type)
if field_type.__doc__:
descriptor['description'] = field_type.__doc__
else:
schema_type = self.__FIELD_TO_SCHEMA_TYPE_MAP.get(
type(field), self.__DEFAULT_SCHEMA_TYPE)
if isinstance(schema_type, dict):
variant_map = schema_type
variant = getattr(field, 'variant', None)
if variant in variant_map:
schema_type = variant_map[variant]
else:
schema_type = variant_map[None]
type_info['type'] = schema_type[0]
if schema_type[1]:
type_info['format'] = schema_type[1]
if type(field) == messages.EnumField:
sorted_enums = sorted([enum_info for enum_info in field.type],
key=lambda enum_info: enum_info.number)
type_info['enum'] = [enum_info.name for enum_info in sorted_enums]
if field.required:
descriptor['required'] = True
if field.default:
if type(field) == messages.EnumField:
descriptor['default'] = str(field.default)
else:
descriptor['default'] = field.default
if field.repeated:
descriptor['items'] = type_info
descriptor['type'] = 'array'
else:
descriptor.update(type_info)
properties[field.name] = descriptor
schema['properties'] = properties
return schema