ProtoBuf serialization missing data even for simple entities

问题

[Update#1]: I've uploaded my modified and fixed "demo" project to https://github.com/sidshetye/SerializersCompare should anyone else be interested in checking out the benchmark.

[Update#2]:I'm seeing that ProtoBufs takes the order of magnitude lead only on subsequent iterations. For a one-time serialization, BinaryFormatter is the one which is an order of magnitude faster. Why? Separate question ...

I'm trying to compare BinaryFormatter, Json.NET and ProtoBuf.NET (got the latter off NuGet today). I'm finding that ProtoBuf outputs no real fields, all nulls and 0s (see below). Plus BinaryFormatter appears to be FAR faster. I basically serialized => deserialized the object and compared

the original with the regenerated object
size in bytes
time in ms

Question

How can I get ProtoBuf to actually spit out the real values and not just (default?) values?
What am I doing wrong for speed? I though ProtoBuf was supposed to be the fastest serializer?

The output I got from my test app is below:

Json: Objects identical
Json in UTF-8: 180 bytes, 249.7054 ms

BinaryFormatter: Objects identical
BinaryFormatter: 512 bytes, 1.7864 ms

ProtoBuf: Original and regenerated objects differ !!
====Regenerated Object====
{
    "functionCall": null,
    "parameters": null,
    "name": null,
    "employeeId": 0,
    "raiseRate": 0.0,
    "addressLine1": null,
    "addressLine2": null
}
ProtoBuf: 256 bytes, 117.969 ms

My test was using a simple entity (see below) inside a console application. System: Windows 8x64, VS2012 Update 1, .NET4.5. By the way, I get the same result using the [ProtoContract] and [ProtoMember(X)] convention. Documentation isn't clear but it appears that DataContract is the newer 'uniformly' support convention (right?)

[Serializable]
[DataContract]
class SimpleEntity
{
    [DataMember(Order = 1)]
    public string functionCall {get;set;}

    [DataMember(Order = 2)]
    public string parameters { get; set; }

    [DataMember(Order = 3)]
    public string name { get; set; }

    [DataMember(Order = 4)]
    public int employeeId { get; set; }

    [DataMember(Order = 5)]
    public float raiseRate { get; set; }

    [DataMember(Order = 6)]
    public string addressLine1 { get; set; }

    [DataMember(Order = 7)]
    public string addressLine2 { get; set; }

    public SimpleEntity()
    {
    }

    public void FillDummyData()
    {
        functionCall = "FunctionNameHere";
        parameters = "x=1,y=2,z=3";

        name = "Mickey Mouse";
        employeeId = 1;
        raiseRate = 1.2F;
        addressLine1 = "1 Disney Street";
        addressLine2 = "Disneyland, CA";
    }
}

For those interested here is the snippet of my AllSerializers class for ProtoBufs

public byte[] SerProtoBuf(object thisObj)
{
    using (MemoryStream ms = new MemoryStream())
    {
        Serializer.Serialize(ms, thisObj);
        return ms.GetBuffer();
    }
}

public T DeserProtoBuf<T>(byte[] bytes)
{

    using (MemoryStream ms = new MemoryStream())
    {
        ms.Read(bytes, 0, bytes.Count());
        return Serializer.Deserialize<T>(ms);
    }
}

回答1:

Firstly, your serialize / deserialize methods are both broken; you are over-reporting the result (GetBuffer(), without Length), and you aren't writing anything into the stream for deserialization. Here's a correct implementation (although you could also use GetBuffer() if you were returning ArraySegment<byte>):

public static byte[] SerProtoBuf(object thisObj)
{
    using (MemoryStream ms = new MemoryStream())
    {
        Serializer.NonGeneric.Serialize(ms, thisObj);
        return ms.ToArray();
    }
}

public static T DeserProtoBuf<T>(byte[] bytes)
{
    using (MemoryStream ms = new MemoryStream(bytes))
    {
        return Serializer.Deserialize<T>(ms);
    }
}

That is why you are getting no data back. Secondly, you don't say how you are timing it, so here's some I've written based on your code (which also includes code to show that it is getting all the values back). Results first:

Via BinaryFormatter:
1 Disney Street
Disneyland, CA
1
FunctionNameHere
Mickey Mouse
x=1,y=2,z=3
1.2

Via protobuf-net:
1 Disney Street
Disneyland, CA
1
FunctionNameHere
Mickey Mouse
x=1,y=2,z=3
1.2

Serialize BinaryFormatter: 112 ms, 434 bytes
Deserialize BinaryFormatter: 113 ms
Serialize protobuf-net: 14 ms, 85 bytes
Deserialize protobuf-net: 19 ms

Analysis:

Both serializers stored the same data; protobuf-net was an order of magnitude faster, and a factor of 5 smaller output. I declare: winner.

Code:

static BinaryFormatter bf = new BinaryFormatter();
public static byte[] SerBinaryFormatter(object thisObj)
{
    using (MemoryStream ms = new MemoryStream())
    {
        bf.Serialize(ms, thisObj);
        return ms.ToArray();
    }
}

public static T DeserBinaryFormatter<T>(byte[] bytes)
{
    using (MemoryStream ms = new MemoryStream(bytes))
    {
        return (T)bf.Deserialize(ms);
    }
}
static void Main()
{
    SimpleEntity obj = new SimpleEntity(), clone;
    obj.FillDummyData();

    // test that we get non-zero bytes
    var data = SerBinaryFormatter(obj);
    clone = DeserBinaryFormatter<SimpleEntity>(data);
    Console.WriteLine("Via BinaryFormatter:");
    Console.WriteLine(clone.addressLine1);
    Console.WriteLine(clone.addressLine2);
    Console.WriteLine(clone.employeeId);
    Console.WriteLine(clone.functionCall);
    Console.WriteLine(clone.name);
    Console.WriteLine(clone.parameters);
    Console.WriteLine(clone.raiseRate);
    Console.WriteLine();

    data = SerProtoBuf(obj);
    clone = DeserProtoBuf<SimpleEntity>(data);
    Console.WriteLine("Via protobuf-net:");
    Console.WriteLine(clone.addressLine1);
    Console.WriteLine(clone.addressLine2);
    Console.WriteLine(clone.employeeId);
    Console.WriteLine(clone.functionCall);
    Console.WriteLine(clone.name);
    Console.WriteLine(clone.parameters);
    Console.WriteLine(clone.raiseRate);
    Console.WriteLine();

    Stopwatch watch = new Stopwatch();
    const int LOOP = 10000;

    watch.Reset();
    watch.Start();
    for (int i = 0; i < LOOP; i++)
    {
        data = SerBinaryFormatter(obj);
    }
    watch.Stop();
    Console.WriteLine("Serialize BinaryFormatter: {0} ms, {1} bytes", watch.ElapsedMilliseconds, data.Length);

    watch.Reset();
    watch.Start();
    for (int i = 0; i < LOOP; i++)
    {
        clone = DeserBinaryFormatter<SimpleEntity>(data);
    }
    watch.Stop();
    Console.WriteLine("Deserialize BinaryFormatter: {0} ms", watch.ElapsedMilliseconds, data.Length);

    watch.Reset();
    watch.Start();
    for (int i = 0; i < LOOP; i++)
    {
        data = SerProtoBuf(obj);
    }
    watch.Stop();
    Console.WriteLine("Serialize protobuf-net: {0} ms, {1} bytes", watch.ElapsedMilliseconds, data.Length);

    watch.Reset();
    watch.Start();
    for (int i = 0; i < LOOP; i++)
    {
        clone = DeserProtoBuf<SimpleEntity>(data);
    }
    watch.Stop();
    Console.WriteLine("Deserialize protobuf-net: {0} ms", watch.ElapsedMilliseconds, data.Length);
}

Lastly, [DataMember(...)] support isn't really the "newer 'uniformly' support convention" - it certainly isn't "newer" - I'm pretty sure it has supported both of those since something like commit #4 (and possibly earlier). It is just options provided for convenience:

not all target platforms have DataMemberAttribute
some people prefer to limit the DTO layer to inbuilt markers
some types are largely outside your control, but may already have those markers (generated data from LINQ-to-SQL, for example)
additionally, note that 2.x allows you to define the model at runtime without having to add attributes (although attributes remain the most convenient way to do it)

来源：https://stackoverflow.com/questions/13715476/protobuf-serialization-missing-data-even-for-simple-entities

标签

serialization

protobuf-net