Step By Step

1、API请求参数解释说明

2、Nuget安装SDK:aliyun-net-sdk-onsmqtt

3、Code Sample

using System;
using Aliyun.Acs.Core;
using Aliyun.Acs.Core.Exceptions;
using Aliyun.Acs.Core.Profile;
using Aliyun.Acs.OnsMqtt.Model.V20200420;

namespace MQTTForIoT
{
    class Program
    {
        static void Main(string[] args)
        {
            // 公网区域实例测试  https://developer.aliyun.com/article/693979?spm=a2c6h.13262185.0.0.15ba5eb5T92u4V
            IClientProfile profile = DefaultProfile.GetProfile("mq-internet-access", "LTAIOZZg********", "v7CjUJCMk7j9aK****************");
            DefaultAcsClient client = new DefaultAcsClient(profile);

            var request = new ApplyTokenRequest();
            request.Resources = "<parent_topic>/#";
            request.InstanceId = "post-cn-6ja********";
            // 当前时间 + 30分钟
            long expireTime = ((DateTime.Now.AddMinutes(30).Ticks - TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1)).Ticks) / 10000);
            request.ExpireTime = expireTime;
            request.Actions = "R,W";
            Console.WriteLine("expireTime: " + expireTime);
            try
            {
                var response = client.GetAcsResponse(request);
                Console.WriteLine(System.Text.Encoding.Default.GetString(response.HttpResponse.Content));
                Console.ReadKey();
            }
            catch (ServerException e)
            {
                Console.WriteLine(e);
            }
            catch (ClientException e)
            {
                Console.WriteLine(e);
            }
        }
    }
}

4、The Result

expireTime: 1603198649047
{"RequestId":"D03E4AEC-3628-4050-A9EA-4CFF111111AF","Token":"1111+XLFl5s/YWJ/MlDz4t/Lq5HC11111128HAMaxYzmBSHQsWXgdISJ1ZJ+2cxaqqEoGlfCn2imhZ4FoNx3kipRDnjsfBujbJGYgJWUr5piesdvDY0i8fNY68mR3UqN9LKVT5IGzKPvooOIjF1CZZ9uU74CT40m4bkmcftVUBP5SM+VepMKCyQgoJWL8b3AQUS1QPxDA2oGf+JBKuN0DyYW6d7mIYhAqXTpVbQw5nNCvKP80Xo0WYK9UHMgTMh9qdrn6MS1rwaP765dpXzvgHC9nWeHX7K80O6vtOU9M8Qn5VrhkP0F1umbOoYs3NfM+WYZIQx4pkViQo6qqkxgbD7le+3be3pC6mQHEsLVxniQFOoUUHHfSw=="}

更多参考

阿里云微服务消息队列Token Java Code Sample
阿里云常见参数获取位置