dyncapnp

go-dyncapnp

go-dyncapnp is a Go library that provides a wrapper around the original capnproto C++ library with CGO. It is designed to parse .capnp schema files on-the-go, without requiring re-compilation. This makes it easier to work with capnproto schemas in Go projects, especially when the schema is being actively developed and updated.

Features

• Written in Go, with CGO bindings to the original Cap'n Proto C++ library
• Parses .capnp schema files on-the-go, without re-compilation
• Capable of encoding/decoding packed/plain Cap'n Proto format binary based on the schema
• Catches C++ exceptions and emits them in Go style

Installation

To use go-dyncapnp in your project, you can simply run:

go get github.com/devsisters/go-dyncapnp

Usage

To use go-dyncapnp, you need to provide a map of files containing capnproto schema definitions, along with any necessary imports and the paths to the schema files. You can then call the ParseFromFiles function to parse the schemas and obtain a map of ParsedSchema objects.

package main

import (
    "fmt"

    "github.com/devsisters/go-dyncapnp"
)

func main() {
	schemaFiles := map[string][]byte{
		"user.capnp": []byte(`
            @0xe4b3f8bd92dc065d;

            struct User {
                id    @0 :UInt64;
                name  @1 :Text;
                email @2 :Text;
            }
        `),
	}

	schemaImports := map[string][]byte{}

	schemaPaths := []string{"user.capnp"}

	schemas, err := dyncapnp.ParseFromFiles(schemaFiles, schemaImports, schemaPaths)
	if err != nil {
		panic(err)
	}

	userFile := schemas["user.capnp"]
	userSchema, err := userFile.Nested("User")
	if err != nil {
		panic(err)
	}

	fmt.Println(userSchema.ShortDisplayName())
	for _, field := range userSchema.AsStruct().Fields() {
		p, err := field.Proto()
		if err != nil {
			panic(err)
		}
		fmt.Printf(" %s @%d %s\n", p.Name(), field.Index(), field.Type().Which())
	}
	// User
	//  id @0 uint64
	//  name @1 text
	//  email @2 text
}

Documentation

For more detailed documentation and additional functions, please visit the official documentation.

Contributing

Contributions are welcome! If you find any bugs or have any suggestions, please open an issue or submit a pull request.

License

This project is licensed under the MIT License - see the LICENSE file for details.