FeiyouG / glsp

Language Server Protocol SDK for Go

This is an early release. Some features are not yet fully implemented.

GLSP

Language Server Protocol SDK for Go.

It enables you to more easily implement language servers by writing them in Go. GLSP contains:

1. all the message structures for easy serialization,
2. a handler for all client methods, and
3. a ready-to-run JSON-RPC 2.0 server supporting stdio, TCP, WebSockets, and Node.js IPC.

All you need to do, then, is provide the features for the language you want to support.

Projects using GLSP:

• Puccini TOSCA Language Server
• zk

References

• go-lsp is another implementation with reduced coverage of the protocol

Minimal Example

package main

import (
	"github.com/tliron/glsp"
	protocol "github.com/tliron/glsp/protocol_3_16"
	"github.com/tliron/glsp/server"
	"github.com/tliron/kutil/logging"

	// Must include a backend implementation. See kutil's logging/ for other options.
	_ "github.com/tliron/kutil/logging/simple"
)

const lsName = "my language"

var version string = "0.0.1"
var handler protocol.Handler

func main() {
	// This increases logging verbosity (optional)
	logging.Configure(1, nil)

	handler = protocol.Handler{
		Initialize:  initialize,
		Initialized: initialized,
		Shutdown:    shutdown,
		SetTrace:    setTrace,
	}

	server := server.NewServer(&handler, lsName, false)

	server.RunStdio()
}

func initialize(context *glsp.Context, params *protocol.InitializeParams) (any, error) {
	capabilities := handler.CreateServerCapabilities()

	return protocol.InitializeResult{
		Capabilities: capabilities,
		ServerInfo: &protocol.InitializeResultServerInfo{
			Name:    lsName,
			Version: &version,
		},
	}, nil
}

func initialized(context *glsp.Context, params *protocol.InitializedParams) error {
	return nil
}

func shutdown(context *glsp.Context) error {
	protocol.SetTraceValue(protocol.TraceValueOff)
	return nil
}

func setTrace(context *glsp.Context, params *protocol.SetTraceParams) error {
	protocol.SetTraceValue(params.Value)
	return nil
}