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#
# Copyright 2016 the original author or authors.
#
# 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.
#
import re
from collections import OrderedDict
from copy import copy
from google.protobuf.descriptor import FieldDescriptor
re_path_param = re.compile(r'/{([^{]+)}')
re_segment = re.compile(r'/(?P<absolute>[^{}/]+)|(?P<symbolic>{[^}]+})')
class DuplicateMethodAndPathError(Exception): pass
class ProtobufCompilationFailedError(Exception): pass
class InvalidPathArgumentError(Exception): pass
def native_descriptors_to_swagger(native_descriptors):
"""
Generate a swagger data dict from the native descriptors extracted
from protobuf file(s).
:param native_descriptors:
Dict as extracted from proto file descriptors.
See DescriptorParser and its parse_file_descriptors() method.
:return: dict ready to be serialized to JSON as swagger.json file.
"""
# gather all top-level and nested message type definitions and build map
message_types_dict = gather_all_message_types(native_descriptors)
message_type_names = set(message_types_dict.iterkeys())
# create similar map for all top-level and nested enum definitions
enum_types_dict = gather_all_enum_types(native_descriptors)
enum_type_names = set(enum_types_dict.iterkeys())
# make sure none clashes and generate set of all names (for sanity checks)
assert not message_type_names.intersection(enum_type_names)
all_type_names = message_type_names.union(enum_type_names)
all_types = {}
all_types.update(message_types_dict)
all_types.update(enum_types_dict)
# gather all method definitions and collect all referenced input/output
# types
types_referenced, methods_dict = gather_all_methods(native_descriptors)
# process all directly and indirectly referenced types into JSON schema
# type definitions
definitions = generate_definitions(types_referenced, all_types)
# process all method and generate the swagger path entries
paths = generate_paths(methods_dict, definitions)
# static part
# last descriptor is assumed to be the top-most one
root_descriptor = native_descriptors[-1]
swagger = {
'swagger': "2.0",
'info': {
'title': root_descriptor['name'],
'version': "version not set"
},
'schemes': ["http", "https"],
'consumes': ["application/json"],
'produces': ["application/json"],
'paths': paths,
'definitions': definitions
}
return swagger
def gather_all_message_types(descriptors):
return dict(
(full_name, message_type)
for full_name, message_type
in iterate_message_types(descriptors)
)
def gather_all_enum_types(descriptors):
return dict(
(full_name, enum_type)
for full_name, enum_type
in iterate_enum_types(descriptors)
)
def gather_all_methods(descriptors):
types_referenced = set()
methods = OrderedDict()
for full_name, service, method in iterate_methods(descriptors):
methods[full_name] = (service, method)
types_referenced.add(method['input_type'].strip('.'))
types_referenced.add(method['output_type'].strip('.'))
return types_referenced, methods
def iterate_methods(descriptors):
for descriptor in descriptors:
package = descriptor['package']
for service in descriptor.get('service', []):
service_prefix = package + '.' + service['name']
for method in service.get('method', []):
# skip methods that do not have http options
options = method['options']
if options.has_key('http'):
full_name = service_prefix + '.' + method['name']
yield full_name, service, method
def iterate_for_type_in(message_types, prefix):
for message_type in message_types:
full_name = prefix + '.' + message_type['name']
yield full_name, message_type
for nested_full_name, nested in iterate_for_type_in(
message_type.get('nested_type', []), full_name):
yield nested_full_name, nested
def iterate_message_types(descriptors):
for descriptor in descriptors:
package = descriptor['package']
top_types = descriptor.get('message_type', [])
for full_name, message_type in iterate_for_type_in(top_types, package):
yield full_name, message_type
def iterate_enum_types(descriptors):
for descriptor in descriptors:
package = descriptor['package']
for enum in descriptor.get('enum_type', []):
enum_full_name = package + '.' + enum['name']
yield enum_full_name, enum
top_types = descriptor.get('message_type', [])
for full_name, message_type in iterate_for_type_in(top_types, package):
for enum in message_type.get('enum_type', []):
enum_full_name = full_name + '.' + enum['name']
yield enum_full_name, enum
def generate_definitions(types_referenced, types):
"""Walk all the referenced types and for each, generate a JSON schema
definition. These may also refer to other types, so keep the needed
set up-to-date.
"""
definitions = {}
wanted = copy(types_referenced)
while wanted:
full_name = wanted.pop()
type = types[full_name]
definition, types_referenced = make_definition(type, types)
definitions[full_name] = definition
for type_referenced in types_referenced:
if not definitions.has_key(type_referenced):
wanted.add(type_referenced)
return definitions
def make_definition(type, types):
if type['_type'] == 'google.protobuf.EnumDescriptorProto':
return make_enum_definition(type), set()
else:
return make_object_definition(type, types)
def make_enum_definition(type):
def make_value_desc(enum_value):
txt = ' - {}'.format(enum_value['name'])
description = enum_value.get('_description', '')
if description:
txt += ': {}'.format(description)
return txt
string_values = [v['name'] for v in type['value']]
default = type['value'][0]['name']
description = (
(type.get('_description', '') or type['name'])
+ '\nValid values:\n'
+ '\n'.join(make_value_desc(v) for v in type['value'])
)
definition = {
'type': 'string',
'enum': string_values,
'default': default,
'description': description
}
return definition
def make_object_definition(type, types):
definition = {
'type': 'object'
}
referenced = set()
properties = {}
for field in type.get('field', []):
field_name, property, referenced_by_field = make_property(field, types)
properties[field_name] = property
referenced.update(referenced_by_field)
if properties:
definition['properties'] = properties
if type.has_key('_description'):
definition['description'] = type['_description']
return definition, referenced
def make_property(field, types):
referenced = set()
repeated = field['label'] == FieldDescriptor.LABEL_REPEATED
def check_if_map_entry(type_name):
type = types[type_name]
if type.get('options', {}).get('map_entry', False):
_, property, __ = make_property(type['field'][1], types)
return property
if field['type'] == FieldDescriptor.TYPE_MESSAGE:
type_name = field['type_name'].strip('.')
maybe_map_value_type = check_if_map_entry(type_name)
if maybe_map_value_type:
# map-entries are inlined
repeated = False
property = {
'type': 'object',
'additionalProperties': maybe_map_value_type
}
elif type_name == 'google.protobuf.Timestamp':
# time-stamp is mapped back to JSON schema date-time string
property = {
'type': 'string',
'format': 'date-time'
}
else:
# normal nested object field
property = {
'$ref': '#/definitions/{}'.format(type_name)
}
referenced.add(type_name)
elif field['type'] == FieldDescriptor.TYPE_ENUM:
type_name = field['type_name'].strip('.')
property = {
'$ref': '#/definitions/{}'.format(type_name)
}
referenced.add(type_name)
elif field['type'] == FieldDescriptor.TYPE_GROUP:
raise NotImplementedError()
else:
_type, format = TYPE_MAP[field['type']]
property = {
'type': _type,
'format': format
}
if repeated:
property = {
'type': 'array',
'items': property
}
if field.has_key('_description'):
property['description'] = field['_description']
return field['name'], property, referenced
def generate_paths(methods_dict, definitions):
paths = {}
def _iterate():
for full_name, (service, method) in methods_dict.iteritems():
http_option = method['options']['http']
yield service, method, http_option
for binding in http_option.get('additional_bindings', []):
yield service, method, binding
def prune_path(path):
"""rid '=<stuff>' pattern from path symbolic segments"""
segments = re_segment.findall(path)
pruned_segments = []
for absolute, symbolic in segments:
if symbolic:
full_symbol = symbolic[1:-1]
pruned_symbol = full_symbol.split('=', 2)[0]
pruned_segments.append('{' + pruned_symbol + '}')
else:
pruned_segments.append(absolute)
return '/' + '/'.join(pruned_segments)
def lookup_input_type(input_type_name):
return definitions[input_type_name.strip('.')]
def lookup_type(input_type, field_name):
local_field_name, _, rest = field_name.partition('.')
properties = input_type['properties']
if not properties.has_key(local_field_name):
raise InvalidPathArgumentError(
'Input type has no field {}'.format(field_name))
field = properties[local_field_name]
if rest:
field_type = field.get('type', 'object')
assert field_type == 'object', (
'Nested field name "%s" refers to field that of type "%s" '
'(.%s should be nested object field)'
% (field_name, field_type, local_field_name))
ref = field['$ref']
assert ref.startswith('#/definitions/')
type_name = ref.replace('#/definitions/', '')
nested_input_type = lookup_input_type(type_name)
return lookup_type(nested_input_type, rest)
else:
return field['type'], field['format']
def make_entry(service, method, http):
parameters = []
verb = None
for verb_candidate in ('get', 'delete', 'patch', 'post', 'put'):
if verb_candidate in http:
verb, path = verb_candidate, http[verb_candidate]
break
if 'custom' in http:
assert verb is None
verb = http['custom']['kind']
path = http['custom']['path']
assert verb is not None
path = prune_path(path)
# for each symbolic segment in path, add a path parameter entry
input_type = lookup_input_type(method['input_type'])
for segment in re_path_param.findall(path):
symbol = segment.split('=')[0]
_type, format = lookup_type(input_type, symbol)
parameters.append({
'in': 'path',
'name': symbol,
'required': True,
'type': _type,
'format': format
})
if 'body' in http:
if 'body' in http: # TODO validate if body lists fields
parameters.append({
'in': 'body',
'name': 'body',
'required': True,
'schema': {'$ref': '#/definitions/{}'.format(
method['input_type'].strip('.'))}
})
entry = {
'operationId': method['name'],
'tags': [service['name'],],
'responses': {
'200': { # TODO: code is 201 and 209 in POST/DELETE?
'description': unicode(""), # TODO: ever filled by proto?
'schema': {
'$ref': '#/definitions/{}'.format(
method['output_type'].strip('.'))
}
},
# TODO shall we prefill with standard error (verb specific),
# such as 400, 403, 404, 409, 509, 500, 503 etc.
}
}
if parameters:
entry['parameters'] = parameters
summary, description = extract_summary_and_description(method)
if summary:
entry['summary'] = summary
if description:
entry['description'] = description
return path, verb, entry
for service, method, http in _iterate():
path, verb, entry = make_entry(service, method, http)
path_dict = paths.setdefault(path, {})
if verb in path_dict:
raise DuplicateMethodAndPathError(
'There is already a {} method defined for path ({})'.format(
verb, path))
path_dict[verb] = entry
return paths
def extract_summary_and_description(obj):
"""
Break raw _description field (if present) into a summary line and/or
detailed description text as follows:
* if text is a single line (not counting white-spaces), then it is a
summary and there is no detailed description.
* if text starts with a non-empty line followied by an empty line followed
by at least one non-empty line, that the 1s line is the summary and the
lines after the empty line is the description.
* in all other cases the text is considered a description and no summary
is generated.
"""
assert isinstance(obj, dict)
summary, description = None, None
text = obj.get('_description', '')
if text:
s, blank, d = (text.split('\n', 2) + ['', ''])[:3] # so we can demux
if not blank.strip():
summary = s
if d.strip():
description = d
else:
description = text
return summary, description
TYPE_MAP = {
FieldDescriptor.TYPE_BOOL: ('boolean', 'boolean'),
FieldDescriptor.TYPE_BYTES: ('string', 'byte'),
FieldDescriptor.TYPE_DOUBLE: ('number', 'double'),
FieldDescriptor.TYPE_ENUM: ('string', 'string'),
FieldDescriptor.TYPE_FIXED32: ('integer', 'int64'),
FieldDescriptor.TYPE_FIXED64: ('string', 'uint64'),
FieldDescriptor.TYPE_FLOAT: ('number', 'float'),
FieldDescriptor.TYPE_INT32: ('integer', 'int32'),
FieldDescriptor.TYPE_INT64: ('string', 'int64'),
FieldDescriptor.TYPE_SFIXED32: ('integer', 'int32'),
FieldDescriptor.TYPE_SFIXED64: ('string', 'int64'),
FieldDescriptor.TYPE_STRING: ('string', 'string'),
FieldDescriptor.TYPE_SINT32: ('integer', 'int32'),
FieldDescriptor.TYPE_SINT64: ('string', 'int64'),
FieldDescriptor.TYPE_UINT32: ('integer', 'int64'),
FieldDescriptor.TYPE_UINT64: ('string', 'uint64'),
# FieldDescriptor.TYPE_MESSAGE:
# FieldDescriptor.TYPE_GROUP:
}