Use upstream slack-go/slack again (#1018)

vendor/github.com/slack-go/slack/rtm.go

@@ -0,0 +1,131 @@
+package slack
+
+import (
+	"context"
+	"net/url"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+const (
+	websocketDefaultTimeout = 10 * time.Second
+	defaultPingInterval     = 30 * time.Second
+)
+
+const (
+	rtmEventTypeAck                 = ""
+	rtmEventTypeHello               = "hello"
+	rtmEventTypeGoodbye             = "goodbye"
+	rtmEventTypePong                = "pong"
+	rtmEventTypeDesktopNotification = "desktop_notification"
+)
+
+// StartRTM calls the "rtm.start" endpoint and returns the provided URL and the full Info block.
+//
+// To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
+func (api *Client) StartRTM() (info *Info, websocketURL string, err error) {
+	ctx, cancel := context.WithTimeout(context.Background(), websocketDefaultTimeout)
+	defer cancel()
+
+	return api.StartRTMContext(ctx)
+}
+
+// StartRTMContext calls the "rtm.start" endpoint and returns the provided URL and the full Info block with a custom context.
+//
+// To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
+func (api *Client) StartRTMContext(ctx context.Context) (info *Info, websocketURL string, err error) {
+	response := &infoResponseFull{}
+	err = api.postMethod(ctx, "rtm.start", url.Values{"token": {api.token}}, response)
+	if err != nil {
+		return nil, "", err
+	}
+
+	api.Debugln("Using URL:", response.Info.URL)
+	return &response.Info, response.Info.URL, response.Err()
+}
+
+// ConnectRTM calls the "rtm.connect" endpoint and returns the provided URL and the compact Info block.
+//
+// To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
+func (api *Client) ConnectRTM() (info *Info, websocketURL string, err error) {
+	ctx, cancel := context.WithTimeout(context.Background(), websocketDefaultTimeout)
+	defer cancel()
+
+	return api.ConnectRTMContext(ctx)
+}
+
+// ConnectRTMContext calls the "rtm.connect" endpoint and returns the
+// provided URL and the compact Info block with a custom context.
+//
+// To have a fully managed Websocket connection, use `NewRTM`, and call `ManageConnection()` on it.
+func (api *Client) ConnectRTMContext(ctx context.Context) (info *Info, websocketURL string, err error) {
+	response := &infoResponseFull{}
+	err = api.postMethod(ctx, "rtm.connect", url.Values{"token": {api.token}}, response)
+	if err != nil {
+		api.Debugf("Failed to connect to RTM: %s", err)
+		return nil, "", err
+	}
+
+	api.Debugln("Using URL:", response.Info.URL)
+	return &response.Info, response.Info.URL, response.Err()
+}
+
+// RTMOption options for the managed RTM.
+type RTMOption func(*RTM)
+
+// RTMOptionUseStart as of 11th July 2017 you should prefer setting this to false, see:
+// https://api.slack.com/changelog/2017-04-start-using-rtm-connect-and-stop-using-rtm-start
+func RTMOptionUseStart(b bool) RTMOption {
+	return func(rtm *RTM) {
+		rtm.useRTMStart = b
+	}
+}
+
+// RTMOptionDialer takes a gorilla websocket Dialer and uses it as the
+// Dialer when opening the websocket for the RTM connection.
+func RTMOptionDialer(d *websocket.Dialer) RTMOption {
+	return func(rtm *RTM) {
+		rtm.dialer = d
+	}
+}
+
+// RTMOptionPingInterval determines how often to deliver a ping message to slack.
+func RTMOptionPingInterval(d time.Duration) RTMOption {
+	return func(rtm *RTM) {
+		rtm.pingInterval = d
+		rtm.resetDeadman()
+	}
+}
+
+// RTMOptionConnParams installs parameters to embed into the connection URL.
+func RTMOptionConnParams(connParams url.Values) RTMOption {
+	return func(rtm *RTM) {
+		rtm.connParams = connParams
+	}
+}
+
+// NewRTM returns a RTM, which provides a fully managed connection to
+// Slack's websocket-based Real-Time Messaging protocol.
+func (api *Client) NewRTM(options ...RTMOption) *RTM {
+	result := &RTM{
+		Client:           *api,
+		IncomingEvents:   make(chan RTMEvent, 50),
+		outgoingMessages: make(chan OutgoingMessage, 20),
+		pingInterval:     defaultPingInterval,
+		pingDeadman:      time.NewTimer(deadmanDuration(defaultPingInterval)),
+		killChannel:      make(chan bool),
+		disconnected:     make(chan struct{}),
+		disconnectedm:    &sync.Once{},
+		forcePing:        make(chan bool),
+		idGen:            NewSafeID(1),
+		mu:               &sync.Mutex{},
+	}
+
+	for _, opt := range options {
+		opt(result)
+	}
+
+	return result
+}