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Protocol Buffers. Portable binary serialization, the Google way. 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
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Protocol Buffers Portable binary serialization, the Google way
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
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
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); }
So why bother? • Compact: • 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.
Look familiar? Closely related to data/service-contracts [DataContract] public class Test1 { [DataMember(Name="a", Order=1, IsRequired=true)] public int A {get;set;} } [DataContract] public class Test3 { [DataMember(Name="c", Order=3, IsRequired=false)] public Test1 C {get;set;} } [ServiceContract] public interface ISearchService { [OperationContract] SearchResponse Search(SearchRequest request); }
Where can we use it? • Communications • Remoting • WCF • Sockets / http (proto-rpc?) • Persistance • File system • Database BLOB • SQL/CLR?
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