Avoid panic when push messages are empty or nil (#13751)

model/push_notification.go

@@ -5,6 +5,7 @@ package model
 
 import (
 	"encoding/json"
+	"errors"
 	"io"
 	"strings"
 )
@@ -83,16 +84,26 @@ func (me *PushNotification) SetDeviceIdAndPlatform(deviceId string) {
 	}
 }
 
-func PushNotificationFromJson(data io.Reader) *PushNotification {
+func PushNotificationFromJson(data io.Reader) (*PushNotification, error) {
+	if data == nil {
+		return nil, errors.New("push notification data can't be nil")
+	}
 	var me *PushNotification
-	json.NewDecoder(data).Decode(&me)
-	return me
+	if err := json.NewDecoder(data).Decode(&me); err != nil {
+		return nil, err
+	}
+	return me, nil
 }
 
-func PushNotificationAckFromJson(data io.Reader) *PushNotificationAck {
+func PushNotificationAckFromJson(data io.Reader) (*PushNotificationAck, error) {
+	if data == nil {
+		return nil, errors.New("push notification data can't be nil")
+	}
 	var ack *PushNotificationAck
-	json.NewDecoder(data).Decode(&ack)
-	return ack
+	if err := json.NewDecoder(data).Decode(&ack); err != nil {
+		return nil, err
+	}
+	return ack, nil
 }
 
 func (ack *PushNotificationAck) ToJson() string {