Develop Reference

Binary Serialization in c#

I am trying to serialize a class object using binary serialization in C#. I have tried and everywhere all I can find that the serialized data goes to a file always in all the examples I have seen.
In my case, I have to store the serialized data in SQL. The following is an example of the method I have created.
//Serializing the List
public void Serialize(Employees emps, String filename)
{
//Create the stream to add object into it.
System.IO.Stream ms = File.OpenWrite(filename);
//Format the object as Binary
BinaryFormatter formatter = new BinaryFormatter();
//It serialize the employee object
formatter.Serialize(ms, emps);
ms.Flush();
ms.Close();
ms.Dispose();
}
How can I get the serialized data directly in a string variable? I don't want to use a file.
Please help.

The easiest way to represent a byte array as a string in C# is with base64 encoding. The below example shows how this would be achieved within your code.
public void Serialize(Employees emps, String filename)
{
//Create the stream to add object into it.
MemoryStream ms = new MemoryStream();
//Format the object as Binary
BinaryFormatter formatter = new BinaryFormatter();
//It serialize the employee object
formatter.Serialize(ms, emps);
// Your employees object serialised and converted to a string.
string encodedObject = Convert.ToBase64String(ms.ToArray());
ms.Close();
}
This creates the string encodedObject. To retrieve the byte array and your serialised object back from the string you will use the below code.
BinaryFormatter bf = new BinaryFormatter();
// Decode the string back to a byte array
byte[] decodedObject = Convert.FromBase64String(encodedObject);
// Create a memory stream and pass in the decoded byte array as the parameter
MemoryStream memoryStream = new MemoryStream(decodedObject);
// Deserialise byte array back to employees object.
Employees employees = bf.Deserialize(memoryStream);

Just use MemoryStream ms = new MemoryStream() instead of your file stream.
You can extract a byte[] for Storage to SQL after serializing by calling ms.ToArray().
And don't forget to put your Stream into a using-Statement, to guarantee correct disposal of the allocated resources.

Serializing Protobuf Object and Sending with ØMQ/ZMQ

I have a protobuf object that I am sending from a C# application (using clrZmq) to a C++ service (using the zmq C++ bindings) on a local machine (for testing). I attempt to send my object from C# using the following
Taurus.Odds odds = Util.GetFakeOdds();
using (var context = ZmqContext.Create())
using (var socket = context.CreateSocket(SocketType.REQ))
{
byte[] buffer = null;
socket.Connect(TARGET); // TARGET = "tcp://127.0.0.1:6500"
Taurus.FeedMux mux = new Taurus.FeedMux();
mux.type = Taurus.FeedMux.Type.ODDS;
mux.odds = odds;
SendStatus status = socket.Send(mux.ToByteArray());
if (status == SendStatus.Sent)
{
int i;
byte[] arr = socket.Receive(buffer, SocketFlags.None, out i);
Taurus.Bet bet = buffer.ToObject<Taurus.Bet>();
}
...
}
Where I am serializing to my Taurus.Odds object to byte[] via the extension method
public static byte[] ToByteArray(this object o)
{
if(o == null)
return null;
BinaryFormatter bf = new BinaryFormatter();
using (MemoryStream ms = new MemoryStream())
{
bf.Serialize(ms, o);
return ms.ToArray();
}
}
I see in my C++ application that the code receives the message, but the C++ ZMQ classes fail to de-serialize it correctly. I have some Java code that send to the C++ code in the same way without issue. My question is, am I sending my object via ZMQ correctly in the above and if not what am I doing wrong?
Thanks for your time.

Here's your error:
I am serializing to my Taurus.Odds object to byte[] via the extension method
...
BinaryFormatter bf = new BinaryFormatter();
...
You seem to be unaware of what BinaryFormatter is. It is in no way related to ProtoBuf. The docs say the following:
Serializes and deserializes an object, or an entire graph of connected objects, in binary format.
This binary format is a .NET-specific implementation detail. And it's very rigid at that, with poor versioning support. It was mainly used in the .NET remoting days, and it's generally considered a bad idea to use it today, as there are much better serializers around.
As you can see, there's no way your C++ app could be able to read that, as it's not in protobuf format.
So throw this method away and replace it with some proper protobuf serializing code, as explained in the protobuf-net docs. You'll need to add [ProtoContract] and [ProtoMember] attributes in your objects. Then you could write something like:
public static byte[] ToByteArray<T>(this T o)
{
if (o == null)
return null;
using (MemoryStream ms = new MemoryStream())
{
ProtoBuf.Serializer.Serialize(ms, o);
return ms.ToArray();
}
}

How to fix OutOfMemoryException when serializing to JSON string?

I have a Class object which contains a property as byte array in it. This class is a Data Contract to my REST service. The byte array property will take any document whose Max Size is limited to 500MB. When I was trying to consume this service and serializing the object I am getting the Memory Out of exception error. Please find the below image
Below is the code snippet
public static string SerializeJSon<T>(T t)
{
MemoryStream stream = new MemoryStream();
DataContractJsonSerializer ds = new DataContractJsonSerializer(typeof(T));
DataContractJsonSerializerSettings s = new DataContractJsonSerializerSettings();
DateTimeFormat dt = new DateTimeFormat("MM/dd/yyyy");
s.DateTimeFormat = dt;
**ds.WriteObject(stream, t);**
string jsonString = Encoding.UTF8.GetString(stream.ToArray());
stream.Close();
return jsonString;
}

Try "do not use 500mb documents in web service calls". THs is the core problem - you try to use a method call mechanism to transport half a gigabyte of data that likely turns into some gigabyte of in memory objects. This is not what web services are designed to do.

DataContractJsonSerializer: serialize object or array (can be both)

I'm accessing the tomtom json api, and the api either returns me an array of objects, or a single object, when an error has happen.
Example:
[{"driverno": "...
Error Example:
{"errorCode": "8011","errorMsg": "request quota reached, error code: 8011"}
The data is accessed WebRequest, WebResponse and they return a stream, which can then be passed to a DataContractJsonSerializer. However, I can't create a serialization class, which accepts both forms of JSON, and the stream can't be passed twice, because the seek function is not supported.
Is there a way, to create a serialization class which supports both types of JSON input?

I found a workaround, where I copy the Stream to a MemoryStream, which enables seeking. I'm not completly settisfied with th solution, becuase it does a Stream copying and the DataContractJsonSerializer twice.
Sample:
string text = File.ReadAllText(PAHT);
text = Regex.Replace(text, "\\{[\\n\\r ]*\"__type", "{\"__type");
// copy to MemoryStream
using (MemoryStream dataStream = new MemoryStream(Encoding.UTF8.GetBytes(text)))
{
DataContractJsonSerializer errorDeserializer = new DataContractJsonSerializer(typeof(RequestError));
RequestError errorSerilaized = (RequestError)errorDeserializer.ReadObject(dataStream);
// check if an error happened
if (errorSerilaized.errorCode == null)
{
// seek the stream to position 0
dataStream.Position = 0;
DataContractJsonSerializer _deserializer = new DataContractJsonSerializer(typeof(NoneErrorSerializationClass));
NoneErrorSerializationClass tripReportsSerialized = (NoneErrorSerializationClass)_deserializer.ReadObject(dataStream);
// ...
}
else
{
MessageBox.Show(errorSerilaized.errorMsg);
}
}

Have trouble deserializing an object when it is sent as a packet

I am trying to learn udp sockets etc.... I created two programs server and client. The client sends a packet to the server, the server bounces it back.
This is the code I use in both programs for converting the data to and from a byte[]
but I am getting an error when converting from byte[]
public static Packet Open(byte[] b)
{
MemoryStream memStream = new MemoryStream();
BinaryFormatter binForm = new BinaryFormatter();
memStream.Write(b, 0, b.Length);
memStream.Seek(0, SeekOrigin.Begin);
object obj = new object();
try
{
// this line here is where the error is occurring
obj = (object)binForm.Deserialize(memStream);
}
catch (Exception er)
{
MessageBox.Show(er.Message);
}
if (obj is Packet)
return (Packet)obj;
else
return null;
}
public byte[] Bundle()
{
BinaryFormatter bf = new BinaryFormatter();
MemoryStream ms = new MemoryStream();
bf.Serialize(ms, this);
return ms.ToArray();
}
If I do this, all from one program it works
Packet p =new Packet();
p.Message="hello";
byte[] data = p.Bundle();
Packet p2 = Packet.Open(data);
MessageBox.Show(p2.Message);
The error I am receiving is "unable to find assembly in "the name of my client program"
AnyIdeas?

It sounds to me like you are serializing a type that is not shared via a reference between both ends. Note: it is not sufficient to have the same class compiled into both, since BinaryFormatter includes the full type name including the assembly, so: it will still count as an unrelated type. The common fix there (and I use the word "fix" entirely incorrectly) is to write an assembly for the DTO and reference that assembly from both client and server. This approach still has many issues, though.
For info, there are other serializers that are compatible with just having a similar class at each end. I'm biased, but I would suggest having a look at protobuf-net; the output is usually significantly smaller, and it isn't tied to the type, meaning the class just has to be broadly similar at each end (it is very version tolerant). Plus it is faster (CPU-wise) too!