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websocket.go
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websocket.go
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package transport
import (
"errors"
"io/ioutil"
"net/http"
"time"
"github.com/gorilla/websocket"
)
const (
upgradeFailed = "Upgrade failed: "
WsDefaultPingInterval = 25 * time.Second
WsDefaultPingTimeout = 5 * time.Second
WsDefaultReceiveTimeout = 60 * time.Second
WsDefaultSendTimeout = 60 * time.Second
WsDefaultBufferSize = 1024 * 32
)
var (
ErrorBinaryMessage = errors.New("Binary messages are not supported")
ErrorBadBuffer = errors.New("Buffer error")
ErrorPacketWrong = errors.New("Wrong packet type error")
ErrorMethodNotAllowed = errors.New("Method not allowed")
ErrorHttpUpgradeFailed = errors.New("Http upgrade failed")
)
type WebsocketConnection struct {
socket *websocket.Conn
transport *WebsocketTransport
}
func (wsc *WebsocketConnection) GetMessage() (message string, err error) {
wsc.socket.SetReadDeadline(time.Now().Add(wsc.transport.ReceiveTimeout))
msgType, reader, err := wsc.socket.NextReader()
if err != nil {
return "", err
}
//support only text messages exchange
if msgType != websocket.TextMessage {
return "", ErrorBinaryMessage
}
data, err := ioutil.ReadAll(reader)
if err != nil {
return "", ErrorBadBuffer
}
text := string(data)
//empty messages are not allowed
if len(text) == 0 {
return "", ErrorPacketWrong
}
return text, nil
}
func (wsc *WebsocketConnection) WriteMessage(message string) error {
wsc.socket.SetWriteDeadline(time.Now().Add(wsc.transport.SendTimeout))
writer, err := wsc.socket.NextWriter(websocket.TextMessage)
if err != nil {
return err
}
if _, err := writer.Write([]byte(message)); err != nil {
return err
}
if err := writer.Close(); err != nil {
return err
}
return nil
}
func (wsc *WebsocketConnection) Close() {
wsc.socket.Close()
}
func (wsc *WebsocketConnection) PingParams() (interval, timeout time.Duration) {
return wsc.transport.PingInterval, wsc.transport.PingTimeout
}
type WebsocketTransport struct {
PingInterval time.Duration
PingTimeout time.Duration
ReceiveTimeout time.Duration
SendTimeout time.Duration
BufferSize int
RequestHeader http.Header
}
func (wst *WebsocketTransport) Connect(url string) (conn Connection, err error) {
dialer := websocket.Dialer{}
socket, _, err := dialer.Dial(url, wst.RequestHeader)
if err != nil {
return nil, err
}
return &WebsocketConnection{socket, wst}, nil
}
func (wst *WebsocketTransport) HandleConnection(
w http.ResponseWriter, r *http.Request) (conn Connection, err error) {
if r.Method != "GET" {
http.Error(w, upgradeFailed+ErrorMethodNotAllowed.Error(), 503)
return nil, ErrorMethodNotAllowed
}
socket, err := websocket.Upgrade(w, r, nil, wst.BufferSize, wst.BufferSize)
if err != nil {
http.Error(w, upgradeFailed+err.Error(), 503)
return nil, ErrorHttpUpgradeFailed
}
return &WebsocketConnection{socket, wst}, nil
}
/**
Websocket connection do not require any additional processing
*/
func (wst *WebsocketTransport) Serve(w http.ResponseWriter, r *http.Request) {}
/**
Returns websocket connection with default params
*/
func GetDefaultWebsocketTransport() *WebsocketTransport {
return &WebsocketTransport{
PingInterval: WsDefaultPingInterval,
PingTimeout: WsDefaultPingTimeout,
ReceiveTimeout: WsDefaultReceiveTimeout,
SendTimeout: WsDefaultSendTimeout,
BufferSize: WsDefaultBufferSize,
}
}