Protocol Buffers - Google's data interchange format (grpc依赖)
https://developers.google.com/protocol-buffers/
98 lines
3.8 KiB
98 lines
3.8 KiB
# Protocol Buffers - Google's data interchange format |
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# Copyright 2008 Google Inc. All rights reserved. |
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# https://developers.google.com/protocol-buffers/ |
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# |
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# Redistribution and use in source and binary forms, with or without |
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# modification, are permitted provided that the following conditions are |
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# met: |
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# |
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# * Redistributions of source code must retain the above copyright |
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# notice, this list of conditions and the following disclaimer. |
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# * Redistributions in binary form must reproduce the above |
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# copyright notice, this list of conditions and the following disclaimer |
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# in the documentation and/or other materials provided with the |
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# distribution. |
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# * Neither the name of Google Inc. nor the names of its |
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# contributors may be used to endorse or promote products derived from |
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# this software without specific prior written permission. |
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# |
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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"""Dynamic Protobuf class creator.""" |
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import hashlib |
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import os |
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from google.protobuf import descriptor_pb2 |
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from google.protobuf import message_factory |
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def _GetMessageFromFactory(factory, full_name): |
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"""Get a proto class from the MessageFactory by name. |
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Args: |
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factory: a MessageFactory instance. |
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full_name: str, the fully qualified name of the proto type. |
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Returns: |
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a class, for the type identified by full_name. |
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Raises: |
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KeyError, if the proto is not found in the factory's descriptor pool. |
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""" |
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proto_descriptor = factory.pool.FindMessageTypeByName(full_name) |
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proto_cls = factory.GetPrototype(proto_descriptor) |
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return proto_cls |
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def MakeSimpleProtoClass(fields, full_name, pool=None): |
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"""Create a Protobuf class whose fields are basic types. |
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Note: this doesn't validate field names! |
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Args: |
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fields: dict of {name: field_type} mappings for each field in the proto. |
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full_name: str, the fully-qualified name of the proto type. |
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pool: optional DescriptorPool instance. |
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Returns: |
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a class, the new protobuf class with a FileDescriptor. |
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""" |
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factory = message_factory.MessageFactory(pool=pool) |
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try: |
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proto_cls = _GetMessageFromFactory(factory, full_name) |
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return proto_cls |
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except KeyError: |
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# The factory's DescriptorPool doesn't know about this class yet. |
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pass |
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# Use a consistent file name that is unlikely to conflict with any imported |
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# proto files. |
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fields_hash = hashlib.sha1() |
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for f_name, f_type in sorted(fields.items()): |
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fields_hash.update(f_name.encode('utf8')) |
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fields_hash.update(str(f_type).encode('utf8')) |
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proto_file_name = fields_hash.hexdigest() + '.proto' |
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package, name = full_name.rsplit('.', 1) |
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file_proto = descriptor_pb2.FileDescriptorProto() |
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file_proto.name = os.path.join(package.replace('.', '/'), proto_file_name) |
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file_proto.package = package |
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desc_proto = file_proto.message_type.add() |
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desc_proto.name = name |
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for f_number, (f_name, f_type) in enumerate(sorted(fields.items()), 1): |
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field_proto = desc_proto.field.add() |
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field_proto.name = f_name |
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field_proto.number = f_number |
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field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL |
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field_proto.type = f_type |
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factory.pool.Add(file_proto) |
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return _GetMessageFromFactory(factory, full_name)
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