agbogomolov/froto

Froto: F# Protocol Buffers

F# Protocol Buffers

What are Protocol Buffers

• https://developers.google.com/protocol-buffers/docs/overview
• https://github.com/google/protobuf
• https://github.com/mgravell/protobuf-net

NuGet

• Froto.Parser - Protobuf Parser
• Froto.Core - Protobuf F# Serialization Framework and low-level WireFormat library.

Build Environment Setup for Visual Studio

• Install Paket for Visual Studio from the "Tools/Extensions and Updates..." menu
• Solution path cannot contain pound sign (#), such as ".../F#/froto/" due to a .net limitation

Status

• v0.2.1 (2016-03-01) Added F# serialization framework to Core, w/full wire format support.
• v0.2.0 (2016-01-26) Complete rewrite of parser to support full proto2 and proto3 syntax
• v0.1.0 (2014-02-28) v0.1.0 Dusted off project and moved to GitHub
• v0.0.5 (2012-11-02) blog Parsing a Protocol Buffers .proto File in F#

Updating from Froto 0.1.0

Core

• Froto.Core was reworked to provide serialization and deserialization of all supported wire types and to minimize buffer copying.

• Code depending on Froto.Core.IO will need to be rewritten to use the following modules and types:

  • Froto.Core.WireFormat
  • Froto.Core.Encoding.RawField
  • Froto.Core.ZeroCopyBuffer and subclasses

• Alternatively, the functions in the Froto.Core.Encoding.Serializer module can provide a slightly higher level of abstraction.

• Or, see next.

• Added a framework for easily constructing serializable class types.

• See Froto.Core.Encoding.MessageBase for an abstract base class which provides the serialization framework, and see Froto.Core.Test/ExampleProtoClass.fs for example usage.

Parser

• The parser now generates an AST based on Discriminated Unions, rather than objects. Froto.Parser.Ast (and the underlying parser) now support the full proto2 and proto3 languages.

• The old primary class, Froto.Parser.ProtoAst.ProtoFile has been renamed to Froto.Parser.Model.ProtoFile and given static factory methods to simplify access from C#, VB.net, etc.

  Note that this model curently only supports a subset of the proto2 language. This will be expanded in later releases to fully support proto2 & proto3.

  • ProtoFile.ParseString(s:string)
  • ProtoFile.ParseStream(streamName:string, stream:System.IO.Stream)
  • ProtoFile.ParseFile(fileName:string)

Todo for parser feature-parity with Google protoc

• Load and parse files from import statements. See https://developers.google.com/protocol-buffers/docs/proto3#importing-definitions
• Verify message identifiers used as field types are actually defined and enum values used in option value assignment are actually defined. Note these must handle forward references.
• For option assignment, verify type of literal matches type of option's message field definition.
• Predefine standard options and enums, or load these from an external "descriptor.proto" file. For standard option definitions, see https://github.com/google/protobuf/blob/master/src/google/protobuf/descriptor.proto#L251
• Generate errors with context including file/line/column when any of the above validations fail (note: this might be better than what protoc reports).
• Record enough source information in the AST to generate SourceCodeInfo (see https://github.com/google/protobuf/blob/master/src/google/protobuf/descriptor.proto#L84)
• Record any other information in the AST needed to generate a complete FileDescriptorProto and FileDescriptorSet.