Language Server Protocol for golang

Language Server Protocol implementation in Go.

Design notes

The package does not include JSON RPC handling as that is better left to other packages.

Example

Example code using github.com/sourcegraph/jsonrpc2

import (
    "fmt"
    "io"
    "context"
    "encoding/json"
    "github.com/sourcegraph/jsonrpc2"
)

func handler(ctx context.Context, conn *jsonrpc2.Conn, req *jsonrpc2.Request) (any, error) {

    switch req.Method {
    case protocol.MethodInitialize:
        var params protocol.InitializeParams
        if err := json.Unmarshal(*req.Params, &params); err != nil {
            return nil, err
        }
    // handle initialize
    case protocol.MethodTextDocumentDidChange:
        var params protocol.DidChangeTextDocumentParams
        if err := json.Unmarshal(*req.Params, &params); err != nil {
            return nil, err
        }
    // handle did change
    default:
        // Respond with a method not found error
        return nil, &jsonrpc2.Error{
            Code:    jsonrpc2.CodeMethodNotFound,
            Message: fmt.Sprintf("Method %s not found", req.Method),
        }
    }
    return nil, nil
}

func (s Server) Run(ctx context.Context, conn io.ReadWriteCloser) error {
    stream := jsonrpc2.NewBufferedStream(conn, jsonrpc2.VSCodeObjectCodec{})
    rpc := jsonrpc2.NewConn(ctx, stream, jsonrpc2.HandlerWithError(s.dispatch))

    select {
    case <-ctx.Done():
        return fmt.Errorf("context closed")
    case <-rpc.DisconnectNotify():
        return nil
    }
}

Author

Henrik Hautakoski henrik@shufflingpixels.com