protobuf网将不序列化从Protobuf.js数据 [英] Protobuf-net won't deserialize data from Protobuf.js
问题描述
我用的protobuf我的Web客户端和服务器（C＃）之间的通信，使用的WebSocket。在客户端，去/序列化是通过 Protobuf.js 并完成，在服务器上，使用protobuf网。
I'm using Protobuf for the communication between my web client and server (C#), using WebSocket. On the client, the de/serialization is done through Protobuf.js and, on the server, using protobuf-net.
问题在于，使用聚合与抽象类时，protobuf网不能反序列化由Protobuf.js发送的数据。
The problem is that, when using aggregation with abstract classes, protobuf-net can't deserialize the data sent by Protobuf.js.
这是堆栈跟踪：
ProtoException: No parameterless constructor found for Base.
at ProtoBuf.Meta.TypeModel.ThrowCannotCreateInstance(Type type) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 1397
at proto_6(Object , ProtoReader )
at ProtoBuf.Serializers.CompiledSerializer.ProtoBuf.Serializers.IProtoSerializer.Read(Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Serializers\CompiledSerializer.cs:line 57
at ProtoBuf.Meta.RuntimeTypeModel.Deserialize(Int32 key, Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Meta\RuntimeTypeModel.cs:line 775
at ProtoBuf.ProtoReader.ReadTypedObject(Object value, Int32 key, ProtoReader reader, Type type) na c:\Dev\protobuf-net\protobuf-net\ProtoReader.cs:line 579
at ProtoBuf.ProtoReader.ReadObject(Object value, Int32 key, ProtoReader reader) na c:\Dev\protobuf-net\protobuf-net\ProtoReader.cs:line 566
at proto_2(Object , ProtoReader )
at ProtoBuf.Serializers.CompiledSerializer.ProtoBuf.Serializers.IProtoSerializer.Read(Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Serializers\CompiledSerializer.cs:line 57
at ProtoBuf.Meta.RuntimeTypeModel.Deserialize(Int32 key, Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Meta\RuntimeTypeModel.cs:line 775
at ProtoBuf.Meta.TypeModel.DeserializeCore(ProtoReader reader, Type type, Object value, Boolean noAutoCreate) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 700
at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type, SerializationContext context) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 589
at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 566
at ProtoBuf.Serializer.Deserialize[T](Stream source) na c:\Dev\protobuf-net\protobuf-net\Serializer.cs:line 77
at ProtobufPolymorphismTest.Program.Main(String[] args) na c:\Desenvolvimento\Testes\ProtobufPolymorphismTest\ProtobufPolymorphismTest\Program.cs:line 30
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
这是合同：
[ProtoContract]
[ProtoInclude(100, typeof(Child))]
abstract class Base
{
[ProtoMember(1)]
public int BaseProperty { get; set; }
}
[ProtoContract]
class Child : Base
{
[ProtoMember(1)]
public float ChildProperty { get; set; }
}
[ProtoContract]
class Request
{
[ProtoMember(1)]
public Base Aggregate { get; set; }
}
这是code重现错误。由于序列化的工作，我只是提供结果作为字节数组。如果有帮助，我可以提供我把步骤获得的序列化值。
And this is the code to reproduce the error. As the serialization is working, I'm only providing the result as a byte array. If it helps, I can provide the steps I took to get to the serialized values.
// This is the object serialized
Child child = new Child() { ChildProperty = 0.5f, BaseProperty = 10 };
Request request = new Request() { Aggregate = child };
// This is the byte representation generated by protobuf-net and Protobuf.js
byte[] protoNet = new byte[] { 10, 10, 162, 6, 5, 13, 0, 0, 0, 63, 8, 10 };
byte[] protoJS = new byte[] { 10, 10, 8, 10, 162, 6, 5, 13, 0, 0, 0, 63 };
// Try to deserialize the protobuf-net data
using (System.IO.MemoryStream ms = new System.IO.MemoryStream(protoNet))
{
request = Serializer.Deserialize<Request>(ms); // Success
}
// Try to deserialize the Protobuf.js data
using (System.IO.MemoryStream ms = new System.IO.MemoryStream(protoJS))
{
request = Serializer.Deserialize<Request>(ms); // ProtoException: No parameterless constructor found for Base.
}
如果我想补充SkipConstructor =真在基类的定义，该错误会更改为MemberAccessException：无法创建一个抽象类和以下堆栈跟踪。如果我删除了抽象基类的定义，它工作正常。
If I add SkipConstructor = true on the Base class definition, the error changes to "MemberAccessException: Cannot create an abstract class" with the following stack trace. If I remove the abstract from the Base class definition, it works as expected.
System.MemberAccessException: Cannot create an abstract class.
at System.Runtime.Serialization.FormatterServices.nativeGetUninitializedObject(RuntimeType type)
at ProtoBuf.BclHelpers.GetUninitializedObject(Type type) na c:\Dev\protobuf-net\protobuf-net\BclHelpers.cs:line 38
at proto_6(Object , ProtoReader )
at ProtoBuf.Serializers.CompiledSerializer.ProtoBuf.Serializers.IProtoSerializer.Read(Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Serializers\CompiledSerializer.cs:line 57
at ProtoBuf.Meta.RuntimeTypeModel.Deserialize(Int32 key, Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Meta\RuntimeTypeModel.cs:line 775
at ProtoBuf.ProtoReader.ReadTypedObject(Object value, Int32 key, ProtoReader reader, Type type) na c:\Dev\protobuf-net\protobuf-net\ProtoReader.cs:line 579
at ProtoBuf.ProtoReader.ReadObject(Object value, Int32 key, ProtoReader reader) na c:\Dev\protobuf-net\protobuf-net\ProtoReader.cs:line 566
at proto_2(Object , ProtoReader )
at ProtoBuf.Serializers.CompiledSerializer.ProtoBuf.Serializers.IProtoSerializer.Read(Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Serializers\CompiledSerializer.cs:line 57
at ProtoBuf.Meta.RuntimeTypeModel.Deserialize(Int32 key, Object value, ProtoReader source) na c:\Dev\protobuf-net\protobuf-net\Meta\RuntimeTypeModel.cs:line 775
at ProtoBuf.Meta.TypeModel.DeserializeCore(ProtoReader reader, Type type, Object value, Boolean noAutoCreate) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 700
at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type, SerializationContext context) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 589
at ProtoBuf.Meta.TypeModel.Deserialize(Stream source, Object value, Type type) na c:\Dev\protobuf-net\protobuf-net\Meta\TypeModel.cs:line 566
at ProtoBuf.Serializer.Deserialize[T](Stream source) na c:\Dev\protobuf-net\protobuf-net\Serializer.cs:line 77
at ProtobufPolymorphismTest.Program.Main(String[] args) na c:\Desenvolvimento\Testes\ProtobufPolymorphismTest\ProtobufPolymorphismTest\Program.cs:line 30
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
我不知道为什么二重presentation通过protobuf网和Protobuf.js不同产生的，但他们似乎都有效，因为它的工作原理如果基类不是抽象的。
I'm not sure why the binary representation generated through protobuf-net and Protobuf.js are different, but they both seem valid as it works if the Base class is not abstract.
为什么任何想法正在发生的事情或解决，而不从基类中删除抽象的方式？
Any ideas on why this is happening or a way to work around without removing the abstract from Base class?
在此先感谢！
更新
这是在code我用来产生通过Protobuf.js字节序列：
This is the code I used to generate the byte serialization through Protobuf.js:
<script src="//raw.githubusercontent.com/dcodeIO/ByteBuffer.js/master/dist/ByteBufferAB.min.js"></script>
<script src="//cdn.rawgit.com/dcodeIO/ProtoBuf.js/master/dist/ProtoBuf.js"></script>
<script type="text/javascript">
// Proto file
var proto = "";
proto += "package ProtobufPolymorphismTest;\r\n\r\n";
proto += "message Base {\r\n";
proto += " optional int32 BaseProperty = 1 [default = 0];\r\n";
proto += " // the following represent sub-types; at most 1 should have a value\r\n";
proto += " optional Child Child = 100;\r\n";
proto += "}\r\n\r\n";
proto += "message Child {\r\n";
proto += " optional float ChildProperty = 1 [default = 0];\r\n";
proto += "}\r\n\r\n";
proto += "message Request {\r\n";
proto += " optional Base Aggregate = 1;\r\n";
proto += "}";
// Build the entities
var protoFile = dcodeIO.ProtoBuf.loadProto(proto);
var requestClass = protoFile.build("ProtobufPolymorphismTest.Request");
var baseClass = protoFile.build("ProtobufPolymorphismTest.Base");
var childClass = protoFile.build("ProtobufPolymorphismTest.Child");
// Build the request
var base = new baseClass();
base.BaseProperty = 10;
base.Child = new childClass();
base.Child.ChildProperty = 0.5;
var request = new requestClass();
request.Aggregate = base;
// Serialize
var bytes = new Uint8Array(request.toArrayBuffer());
var str = "new byte[] { " + bytes.join(", ") + " };";
console.log(str);
</script>
解决方法
正如马克解释说，protobuf网不支持多态时，场顺序相反。作为一种变通方法，具体到Protobuf.js，您可以更改.proto文件中的字段的顺序为它以正确的顺序序列。
As Marc explained, protobuf-net doesn't support polymorphism when the field order is inverted. As a workaround, specific to Protobuf.js, you can change the order of the fields in the .proto file for it to serialize in the correct order.
在我的情况下，改变.proto文件到以下解决了这个问题：
In my case, changing the .proto file to the following solved the problem:
package ProtobufPolymorphismTest;
message Base {
// the following represent sub-types; at most 1 should have a value
optional Child Child = 100;
optional int32 BaseProperty = 1 [default = 0];
}
message Child {
optional float ChildProperty = 1 [default = 0];
}
message Request {
optional Base Aggregate = 1;
}
（注意选购儿童儿童= 100; 的在的的 BaseProperty ）
推荐答案
长期和短期的它是protobuf网的polymorpism支持，预计将第一消息中的分型（或更具体地说：任何对象，该类型将数据提供之前固定的）。在JS输出，现场数据 BaseProperty 来自第一 - 完全合理的，也许。但是，由于没有包罗万象的协议传承应该如何行为的定义，protobuf网的实现只是真的曾经打算与自己的工作。在字节而言，这实际上归结为其中场标记162，6（和相关联的长度/数据，5，13，0，0，0，63）的显示。
The long and short of it is that protobuf-net's polymorpism support expects the sub-type to be first in the message (or more specifically: for any object, the type will be fixed before data is provided). In the js output, the field data for BaseProperty comes first - perfectly reasonably, perhaps. But since there is no over-arching protocol definition of how inheritance should behave, protobuf-net's implementation was only really ever intended to work with itself. In terms of the bytes, this actually comes down to where the field marker "162, 6" (and the associated length/data, "5, 13, 0, 0, 0, 63") appears.
该库的可以的可能被修改，以允许任何字段顺序多态，但是：它会采取一些努力。我知道，这是的一般的预期来处理任何顺序领域，但由于这已经是规范之外，我并没有专注于这一点。所有其他数据字段都接受以任意顺序 - 只有多态性以这种方式工作
The library could potentially be reworked to allow any field order for polymorphism, but: it would take some effort. I am aware that it is usually expected to process fields in any order, but since this is already outside of the specification, I didn't focus on this. All other data fields are accepted in any order - only polymorphism works this way.
在一般情况下：，因为的多态性是不规范的一部分，我会强烈建议图书馆之间工作时，避免了多态。
In the general case: since polymorphism is not part of the specification, I would strongly recommend avoiding polymorphism when working between libraries.
请注意：你可能迫使这确保多态性领域的合作的下（数字），比的数据字段
Note: you can probably force this to work by ensuring the polymorphism fields are lower (numerically) than the data fields.
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