I have a frontend aplication, that connects to websocket and try to serve json-rpc2 to call client side from server. What is the best way to create *rpc.Client for it in a server application written in Go with "github.com/gorilla/websocket"? I tried to use UnderlyingConn() of *websocket.Conn: jsonrpc2.NewClient(conn.UnderlyingConn()), but it does not work.
I provide NewClient with io.ReadWriteCloser implementation which convert read/writes to websocket operations, thanks to powerman.
package jsonrpc2ws
import (
"github.com/powerman/rpc-codec/jsonrpc2"
"github.com/gorilla/websocket"
"encoding/json"
"io"
"sync"
)
func NewClient(ws *websocket.Conn) *jsonrpc2.Client {
c := &client{
ws:ws,
}
c.initRead()
c.initWrite()
return jsonrpc2.NewClient(c)
}
type client struct {
w *io.PipeWriter
r *io.PipeReader
ws *websocket.Conn
err error // io error
mu sync.Mutex // protects err
}
func (x *client) error() (err error) {
x.mu.Lock()
err = x.err
x.mu.Unlock()
return
}
func (x *client) setError (err error) {
x.mu.Lock()
if x.err != nil {
x.err = err
}
x.mu.Unlock()
}
func (x *client) initRead(){
var w *io.PipeWriter
x.r, w = io.Pipe()
go func(){
_,b,err := x.ws.ReadMessage()
for ; x.error() == nil && err == nil; _,b,err = x.ws.ReadMessage(){
_,err = w.Write(b)
}
x.setError(err)
w.Close()
} ()
}
func (x *client) initWrite(){
var r *io.PipeReader
r,x.w = io.Pipe()
go func(){
dec := json.NewDecoder(r)
var b json.RawMessage
err := dec.Decode(&b)
for ; x.error() == nil && err == nil; err = dec.Decode(&b){
err = x.ws.WriteMessage(websocket.TextMessage, b)
}
x.setError(err)
r.Close()
} ()
}
func (x *client) Write(p []byte) (int, error){
if x.error() != nil {
return 0, x.error()
}
return x.w.Write(p)
}
func (x *client) Read(p []byte) (int, error){
if x.error() != nil {
return 0, x.error()
}
return x.r.Read(p)
}
func (x *client) Close() error{
x.ws.Close()
x.w.Close()
x.r.Close()
return nil
}