This library contains some useful tools for anyone using Protobuf encoded messages in their swift-nio stack. If not for the dependency on SwiftProtobuf and thus Foundation, this would likely just be a pull request for swift-nio-extras. As it is, I'm happy to keep it here.

The functionality here was inspired by the protobuf codecs in Netty.

dependencies: [
    .package(url: "https://github.com/AlanQuatermain/swift-nio-protobuf.git", .upToNextMinor(from: "0.1.0")),
],

• VarintFrameDecoder and VarintLengthFieldPrepender: Implements VarInt64-based length encoding of messages from up/down the stack. Anything passed to the prepender will be prepended with its length, varint-encoded. The decoder will read varints and accumulate the appropriate number of bytes from its own input, passing each slice to the next handler once all bytes have arrived.
• ProtobufDecoder and ProtobufEncoder: An encoder/decoder pair that encoder or decode a protobuf message type specified as a generic parameter. Note that both will send all input bytes into the SwiftProtobuf encoder/decoder. It is anticipated that you'll want to chain these together to parse or generate standard varint32-delimited protobuf streams.