PLT-7809: Add support for Kopano Webmeetings WebRTC server (#7590)

* Add support for Kopano Webmeetings WebRTC server

Add an option to select which WebRTC server to use and add support to
use Kopano Webmeetings as backend instead of Janus. If the new
configuration is not set, WebRTC assumes Janus is used as backend.

* Fixup: remove redundant case. default to janus

* Fixup: use GatewayAdminUrl as direct prefix to admin URL entry point

* Fixup: consumeAndClose

4 files changed, 59 insertions, 9 deletions

diff --git a/app/webrtc.go b/app/webrtc.go
index 2d0bb0708..d8684f1fd 100644
--- a/app/webrtc.go
+++ b/app/webrtc.go
@@ -23,8 +23,9 @@ func GetWebrtcInfoForSession(sessionId string) (*model.WebrtcInfoResponse, *mode
 	}
 
 	result := &model.WebrtcInfoResponse{
-		Token:      token,
-		GatewayUrl: *utils.Cfg.WebrtcSettings.GatewayWebsocketUrl,
+		Token:       token,
+		GatewayUrl:  *utils.Cfg.WebrtcSettings.GatewayWebsocketUrl,
+		GatewayType: *utils.Cfg.WebrtcSettings.GatewayType,
 	}
 
 	if len(*utils.Cfg.WebrtcSettings.StunURI) > 0 {
@@ -48,6 +49,16 @@ func GetWebrtcToken(sessionId string) (string, *model.AppError) {
 		return "", model.NewAppError("WebRTC.getWebrtcToken", "api.webrtc.disabled.app_error", nil, "", http.StatusNotImplemented)
 	}
 
+	switch strings.ToLower(*utils.Cfg.WebrtcSettings.GatewayType) {
+	case "kopano-webmeetings":
+		return GetKopanoWebmeetingsWebrtcToken(sessionId)
+	default:
+		// Default to Janus.
+		return GetJanusWebrtcToken(sessionId)
+	}
+}
+
+func GetJanusWebrtcToken(sessionId string) (string, *model.AppError) {
 	token := base64.StdEncoding.EncodeToString([]byte(sessionId))
 
 	data := make(map[string]string)
@@ -65,7 +76,7 @@ func GetWebrtcToken(sessionId string) (string, *model.AppError) {
 		defer consumeAndClose(rp)
 		return "", model.AppErrorFromJson(rp.Body)
 	} else {
-		janusResponse := model.GatewayResponseFromJson(rp.Body)
+		janusResponse := model.JanusGatewayResponseFromJson(rp.Body)
 		if janusResponse.Status != "success" {
 			return "", model.NewAppError("getWebrtcToken", "api.webrtc.register_token.app_error", nil, "", http.StatusInternalServerError)
 		}
@@ -74,6 +85,29 @@ func GetWebrtcToken(sessionId string) (string, *model.AppError) {
 	return token, nil
 }
 
+func GetKopanoWebmeetingsWebrtcToken(sessionId string) (string, *model.AppError) {
+	data := make(map[string]string)
+	data["type"] = "Token"
+	data["id"] = sessionId
+
+	rq, _ := http.NewRequest("POST", *utils.Cfg.WebrtcSettings.GatewayAdminUrl+"/auth/tokens", strings.NewReader(model.MapToJson(data)))
+	rq.Header.Set("Content-Type", "application/json")
+	rq.Header.Set("Authorization", "Bearer "+*utils.Cfg.WebrtcSettings.GatewayAdminSecret)
+
+	if rp, err := utils.HttpClient(true).Do(rq); err != nil {
+		return "", model.NewAppError("WebRTC.Token", "model.client.connecting.app_error", nil, err.Error(), http.StatusInternalServerError)
+	} else if rp.StatusCode >= 300 {
+		defer consumeAndClose(rp)
+		return "", model.AppErrorFromJson(rp.Body)
+	} else {
+		kwmResponse := model.KopanoWebmeetingsResponseFromJson(rp.Body)
+		if kwmResponse.Value == "" {
+			return "", model.NewAppError("getWebrtcToken", "api.webrtc.register_token.app_error", nil, "", http.StatusInternalServerError)
+		}
+		return kwmResponse.Value, nil
+	}
+}
+
 func GenerateTurnPassword(username string, secret string) string {
 	key := []byte(secret)
 	h := hmac.New(sha1.New, key)
diff --git a/model/config.go b/model/config.go
index d9fbca451..7becddff4 100644
--- a/model/config.go
+++ b/model/config.go
@@ -465,6 +465,7 @@ type NativeAppSettings struct {
 
 type WebrtcSettings struct {
 	Enable              *bool
+	GatewayType         *string
 	GatewayWebsocketUrl *string
 	GatewayAdminUrl     *string
 	GatewayAdminSecret  *string
diff --git a/model/webrtc.go b/model/webrtc.go
index fa15a4b71..3318128fe 100644
--- a/model/webrtc.go
+++ b/model/webrtc.go
@@ -11,19 +11,24 @@ import (
 type WebrtcInfoResponse struct {
 	Token        string `json:"token"`
 	GatewayUrl   string `json:"gateway_url"`
+	GatewayType  string `json:"gateway_type"`
 	StunUri      string `json:"stun_uri,omitempty"`
 	TurnUri      string `json:"turn_uri,omitempty"`
 	TurnPassword string `json:"turn_password,omitempty"`
 	TurnUsername string `json:"turn_username,omitempty"`
 }
 
-type GatewayResponse struct {
+type JanusGatewayResponse struct {
 	Status string `json:"janus"`
 }
 
-func GatewayResponseFromJson(data io.Reader) *GatewayResponse {
+type KopanoWebmeetingsResponse struct {
+	Value string `json:"value"`
+}
+
+func JanusGatewayResponseFromJson(data io.Reader) *JanusGatewayResponse {
 	decoder := json.NewDecoder(data)
-	var o GatewayResponse
+	var o JanusGatewayResponse
 	err := decoder.Decode(&o)
 	if err == nil {
 		return &o
@@ -51,3 +56,13 @@ func WebrtcInfoResponseFromJson(data io.Reader) *WebrtcInfoResponse {
 		return nil
 	}
 }
+
+func KopanoWebmeetingsResponseFromJson(data io.Reader) *KopanoWebmeetingsResponse {
+	decoder := json.NewDecoder(data)
+	var o KopanoWebmeetingsResponse
+	err := decoder.Decode(&o)
+	if err == nil {
+		return &o
+	}
+	return nil
+}
diff --git a/model/webrtc_test.go b/model/webrtc_test.go
index 4b8b26dc1..30a92f2b1 100644
--- a/model/webrtc_test.go
+++ b/model/webrtc_test.go
@@ -27,20 +27,20 @@ func TestWebrtcInfoResponseToFromJson(t *testing.T) {
 	}
 }
 
-func TestGatewayResponseFromJson(t *testing.T) {
+func TestJanusGatewayResponseFromJson(t *testing.T) {
 	if testing.Short() {
 		t.SkipNow()
 	}
 
 	// Valid Gateway Response
 	s1 := `{"janus": "something"}`
-	g1 := GatewayResponseFromJson(strings.NewReader(s1))
+	g1 := JanusGatewayResponseFromJson(strings.NewReader(s1))
 
 	CheckString(t, g1.Status, "something")
 
 	// Malformed JSON
 	s2 := `{"wat"`
-	g2 := GatewayResponseFromJson(strings.NewReader(s2))
+	g2 := JanusGatewayResponseFromJson(strings.NewReader(s2))
 
 	if g2 != nil {
 		t.Fatal("expected nil")