1. Portable binary serialization, the Google way
Protocol Buffers
Portable binary serialization, the Google way

2. What problem? For high volume work, no ideal serializer:
Xml/data-contracts: (relatively) expensive to process; large due to repeated tags
Soap: as xml, but more
BinaryFormatter (/NDCS): proprietary closed [non-]standard
Bespoke: lots of work; lots of potential for error

3. What is protobuf? Protocol Buffers defines two things:
A compact binary serialization format (pb)
A text-based descriptor language (.proto)
Implementation specific:
Runtime serialization library / code
.proto parser / code generator
protobuf-net is one of 3 in-progress efforts for .NET

4. What is a .proto? Yet another descriptor language... message Test1 {
required int32 a = 1; }
message Test3 {
optional Test1 c = 3;
service SearchService {
rpc Search (SearchRequest) returns (SearchResponse);

5. So why bother? Compact: Portable: Fast:
no string field names (contrast: XmlSerializer; DataContractSerializer)
uses variable-length encoding where sensible
minimal framing overhead
Portable:
cross-platform (contrast: BinaryFormatter)
extensible (roundtrip-safe)
(protobuf-net works with .NET 2.0; .NET 3.0; CF 2.0; CF 3.0; Silverlight 2.0; Mono)
Fast:
efficient to parse
Optimised for common scenarios, but doesn’t support every complex worst-case scenario.

6. Look familiar? Closely related to data/service-contracts
[DataContract]
public class Test1 {
[DataMember(Name="a", Order=1, IsRequired=true)]
public int A {get;set;} }
public class Test3
[DataMember(Name="c", Order=3, IsRequired=false)]
public Test1 C {get;set;}
[ServiceContract]
public interface ISearchService
[OperationContract]
SearchResponse Search(SearchRequest request);

7. Demo

8. Where can we use it? Communications Persistance Remoting WCF
Sockets / http (proto-rpc?)
Persistance
File system
Database BLOB
SQL/CLR?

9. Existing data? Works with common frameworks:
WCF
LINQ-based data-contracts
XmlType / XmlElement
Can be used to replace, or in parallel with, standard serializers:
ISerializable
IXmlSerializable
Custom attributes for full control
Can also be specified at the class (rather than member) for use with partial classes