go-raw-protobuf

A lightweight Go library for encoding and decoding Protocol Buffers (protobuf) without requiring .proto files.

This library provides a simple way to work with protobuf messages dynamically, eliminating the need for precompiled .proto definitions. It supports basic protobuf wire types and is designed for flexibility and ease of use.

Disclaimer: This library is a work in progress and may have rough edges, but it gets the job done! Contributions and feedback are welcome.

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Installation

Add the library to your project using go get:

go get github.com/2xxn/go-raw-protobuf

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Supported Types

The library currently supports the following protobuf wire types:

Decoding:

• Varint (decoded as uint64)
• Length-delimited (decoded as []byte or string if it passes utf-8 validation)
• Fixed32 as [4]byte
• Fixed64 as [8]byte

Encoding:

• integers (int, int32, int64, uint, uint32, uint64, bool) (encoded as varint)
• floating-point numbers (float32, float64) (encoded as LittleEndian fixed32/fixed64)
• strings (string) (encoded as length-delimited)
• byte slices ([]byte) (encoded as length-delimited)
• arrays ([]interface{}, []int, []string) (encoded as length-delimited, nested message)
• nested arrays ([][]interface{}) (encoded as length-delimited, nested message)

No support for repeated fields yet

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Usage

If you want to verify the encoded data manually, feel free to visit protobuf-decoder.netlify.app

Encoding a Message without a struct

Convert a slice of data into a protobuf-encoded byte slice:

data := []interface{}{123.456, "hello there!", []interface{}{true, "test"}}
encoded := Encode(data)
fmt.Println(hex.EncodeToString(encoded)) // Output: Protobuf-encoded hex string

Decoding a Message without a struct

Decode a protobuf-encoded byte slice back into a slice of data:

data, _ := hex.DecodeString("08aefb8999d532120e496e697469616c20636f6d6d6974")
decoded := Decode(data)
fmt.Println(decoded) // Output: Decoded data as a slice

Encoding a Message with a struct

type ProtoStruct struct {
	Id             int     `protoField:"1"`
	Username       string  `protoField:"2"`
	Email          string  `protoField:"3"`
	TestFloat      float32 `protoField:"4"`
	IsAdmin        bool    `protoField:"5"`
	TestOtherFloat float64 `protoField:"6"`
}

data := &ProtoStruct{
	Id:             4588743,
	Username:       "hello",
	Email:          "admin@example.com",
	TestFloat:      1.2,
	TestOtherFloat: 1.23456789,
	IsAdmin:        true,
}

encoded := EncodeStruct(data)
fmt.Println(hex.EncodeToString(encoded)) // Output: Protobuf-encoded hex string

Decoding a Message with a struct

type ProtoStruct struct {
    Id             int     `protoField:"1"`
    Username       string  `protoField:"2"`
    Email          string  `protoField:"3"`
    TestFloat      float32 `protoField:"4"`
    IsAdmin        bool    `protoField:"5"`
    TestOtherFloat float64 `protoField:"6"`
}

data, _ := hex.DecodeString("08c7899802120568656c6c6f1a1161646d696e406578616d706c652e636f6d259a99993f2801311bde8342cac0f33f")

var s ProtoStruct
decoded := DecodeStruct(data, &s) // DecodeToProtoStruct will panic if the struct is not valid

fmt.Printf("%+v\n", s)

Old-fashioned way, still works

Encoding a Message

Convert a slice of data into a protobuf-encoded byte slice:

data := []interface{}{123.456, "hello there!", []interface{}{true, "test"}}
encoded := EncodeProto(ArrayToProtoParts(data))
fmt.Println(hex.EncodeToString(encoded)) // Output: Protobuf-encoded hex string

Decoding a Message

Decode a protobuf-encoded byte slice back into a slice of data:

data, _ := hex.DecodeString("08aefb8999d532120e496e697469616c20636f6d6d6974")
decoded := ProtoPartsToArray(DecodeProto(data).Parts)
// Loop through DecodeProto(data).Parts yourself if dealing with floating-point numbers etc or else fixed32/fixed64 will be returned as []byte and no different from utf8 invalid length-delimited data
fmt.Println(decoded) // Output: Decoded data as a slice

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Contributing

Found a bug or have an idea for improvement? Open an issue or submit a pull request!

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