Question

我编写了一个C＃程序，该程序以异步方式对供应商进行API调用以生成提交令牌。然后，将此令牌附加到任何表单发布有效负载上，以验证其完整性。它可以作为独立的.Net 4.6.1应用程序很好地工作。我遇到的问题是将其集成到CMS中。与CMS支持人员交谈后，他们要求我将其改为同步操作。我在转换代码时遇到问题。特别是有关检索令牌后发布表单的部分。

这是我最初编写的源代码。显然，AppID和机密已被删除。

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.IO;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Web.UI;

namespace FormSubmission
{
    public partial class _Default : Page
    {
        protected async void Page_Load(object sender, EventArgs e)
        {
            var start = new Start();
            await start.KickOff();
        }

        public class Start
        {

            public async Task<String> KickOff()
            {
                var auth = new Authentication();
                var token = await auth.Authenticate();

                // return await Task.FromResult(token);
                // //Task.FromResult(token);
                if (!String.IsNullOrEmpty(token))
                {
                    var form = new FormSubmission();
                    var formFields = new Form();
                    formFields.createMethod = "SubmitForm";
                    formFields.email = "email@email.com";
                    formFields.mobile = "555-555-5555";
                    formFields.remark = "Hello, hope this works";
                    formFields.attr.attr3 = "mnc";
                    formFields.attr.attr6 = "1000";
                    formFields.attr.attr10 = "first name";
                    formFields.attr.attr11 = "lastname";
                    formFields.attr.attr14 = "City";
                    formFields.attr.attr15 = "State";
                    formFields.attr.attr18 = "USA";
                    formFields.attr.attr25 = "USA";
                    formFields.attr.attr28 = "Newsletter";

                    var serializer = JsonSerializer.Create();

                    var optionsString = new StringBuilder();
                    var writer = new StringWriter(optionsString);

                    serializer.Serialize(writer, formFields);

                    await form.Submit(token, optionsString.ToString());
                }

                return await Task.FromResult("");

            }
        }

        public class Authentication 
        {
            private const string appId = "XXXXXXXXXXXXX";
            private const string secret = "XXXXXXXXXXXXXXXXXXXXXX";

            public async Task<String> Authenticate()
            {
                string url = "https://api-url-goes-here";
                string token = "";

                try
                {

                    using (var client = new HttpClient())
                    {
                        var responseMessage = await client.GetAsync(url + appId + "&secret=" + secret);
                        var content = await responseMessage.Content.ReadAsStringAsync();
                        var contentObject = JObject.Parse(content);
                        token = contentObject["access_token"].ToString();
                        return token;
                    };
                }
                catch (Exception e)
                {
                    throw new Exception("Access token not found");
                }

            }
        }

        public class FormSubmission
        {

            public async Task Submit(string token, string json)
            {
                using (var client = new HttpClient())
                {
                    var message = await client.PostAsync(
                        "https://api-url-goes-here/access_token=" + token,
                        new StringContent(json, Encoding.UTF8, "application/json"));

                    var content = await message.Content.ReadAsStringAsync();
                    Console.Write(content);
                }
            }
        }
    }
}

在与我的CMS版本的.Net匹配的新.Net项目中运行时，此代码非常有用。但是再次，他们告诉我它不支持异步操作（这看起来很奇怪，但是我显然不是一个出色的C＃开发人员）

所以我已经重写了它。

public class Attr
{
    public string attr3;
    public string attr6;
    public string attr10;
    public string attr11;
    public string attr14;
    public string attr15;
    public string attr18;
    public string attr25;
    public string attr28;
}

public class FormSubmission
{
    public string mobile;
    public string email;
    public string remark;
    public string createMethod;
    public Attr attr = new Attr();
}
protected void Page_Load(object sender, EventArgs e)
{

    string token = fetchToken();


    var formFields = new FormSubmission();
    formFields.createMethod = "SubmitForm";
    formFields.email = "email@email.com";
    formFields.mobile = "5555555555";
    formFields.remark = "Non sync";
    formFields.attr.attr3 = "mnc";
    formFields.attr.attr6 = "1000";
    formFields.attr.attr10 = "first name";
    formFields.attr.attr11 = "last name";
    formFields.attr.attr14 = "City";
    formFields.attr.attr15 = "State";
    formFields.attr.attr18 = "USA";
    formFields.attr.attr25 = "USA";
    formFields.attr.attr28 = "Newsletter";

    var serializer = JsonSerializer.Create();

    var optionsString = new StringBuilder();
    var writer = new StringWriter(optionsString);

    serializer.Serialize(writer, formFields);


    var x = new submitForm();
    x.Submit(token, optionsString.ToString());
}

protected string fetchToken()
{

    string appId = "xxxxxxxxxxxxxxx";
    string secret = "xxxxxxxxxxxxxxxxxxxxxxxxxx";
    string url = "https://api-url-goes-here/security/accesstoken?grant_type=client_credentials&appid=";

    string token;

    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url + appId + "&secret=" + secret);
        request.Method = "GET";
        request.KeepAlive = false;
        request.ContentType = "appication/json";

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        string myResponse = "";

        using (System.IO.StreamReader sr = new System.IO.StreamReader(response.GetResponseStream()))
        {
            myResponse = sr.ReadToEnd();
        }

        JObject jobj = JObject.Parse(myResponse);
        token = jobj["access_token"].ToString();

        return token;


    }
    catch (Exception e)
    {
        return e.ToString();
    }

}

public class submitForm
{
    public void Submit(string token, string json)
    {
        using (var client = new HttpClient())
        {
            var message = client.PostAsync("https://api-url-goes-here/v1/customers?access_token=" + token,
                new StringContent(json, Encoding.UTF8, "application/json"));

        }
    }
}

如您所见，它应该是相同的代码。我正在运行的问题，如SubmitForm类上的Submit方法。当我运行程序并打开提琴手时，我可以看到为获取令牌而进行的请求。并且接收到令牌。是SubmitForm类给了我一些问题。我什至没有在提琴手中看到POST请求。谁能帮我吗？

这是给我麻烦的课。

public class submitForm
{
    public void Submit(string token, string json)
    {
        using (var client = new HttpClient())
        {
            var message = client.PostAsync("https://api-url-goes-here/v1/customers?access_token=" + token,
                new StringContent(json, Encoding.UTF8, "application/json"));

        }
    }
}

Answer 1

public void Submit(string token, string json)
{
    using (var client = new HttpClient())
    {
        var message = client.PostAsync("https://api-url-goes-here/v1/customers?access_token=" + token,
            new StringContent(json, Encoding.UTF8, "application/json"));

    }
}

这并不像您期望的那样，因为message现在是Task，而不是您希望的响应，因为您没有等到PostAsync完成。

要使其同步，您有两个选择：

致电.GetAwaiter().GetResult()。可以在以前使用await的任何地方使用该方法，并且不存在该方法的同步版本。例如：

public void Submit(string token, string json)
{
    using (var client = new HttpClient())
    {
        var message = client.PostAsync(
            "https://api-url-goes-here/access_token=" + token,
            new StringContent(json, Encoding.UTF8, "application/json")).GetAwaiter().GetResult();

        var content = message.Content.ReadAsStringAsync().GetAwaiter().GetResult();
        Console.Write(content);
    }
}

here描述了使用.GetAwaiter().GetResult()而非仅使用.Result的原因（主要是因为引发异常的方式）。

或者，

使用HttpWebRequest而不是HttpClient发出相同的请求，就像您在代码的另一部分中所做的一样，因此不必处理仅异步方法。

Answer 2

这可能不是您想听到的，但您不应将异步转换为同步方法。您可能会很幸运，当您使用GetAwaiter().GetResult()时它们可以工作，但是存在死锁或它们无法正常工作的风险。您可以先使用Task.Run然后使用GetAwaiter().GetResult()来运行它们，但这将旋转另一个线程，因此效率不高，并且您的代码仍在阻塞。使它比同步代码慢，因为它必须旋转另一个线程。另外，它肯定会分配gc必须处理的更多内存。

您还应该使用Async后缀来命名异步方法。

如何转换aysnc帖子以进行同步？

2 个答案: