带有json返回的HttpClient表单提交

Question

提前致谢。

我们正在开发 oAuth2 流程，需要一些帮助。给出的要求是使用嵌入的表单变量 POST 到服务器，并期望服务器以 JSON 格式响应。该文档有一个类似的序列，涉及一个返回 JSON 的 GET 请求，并且一个非常相似的方法可以很好地获取响应。但是，在这种情况下，它会给出一个对象引用错误，说明响应为空。我们从服务器收到一条内容长度为 1929 的 200 OK 消息，它说内容类型是 application/json，所以我完全有理由相信内容存在于某处。

public rsAccessToken Signup(string Code, string State, string redirect_uri)
        {

            HttpClient client = new HttpClient();
            rsAccessToken rt = null;
            HttpResponseMessage response = null;
            client.BaseAddress = new Uri(URLtoken);
            string grant_type = "authorization_code";

            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
            var byteArray = Encoding.ASCII.GetBytes(string.Format("{0}:{1}", clientid, secret));
            client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, URLtoken);
            var parameters = new Dictionary<string, string> { { "grant_type", grant_type }, { "code", Code }, { "state", State }, { "redirect_uri", redirect_uri } };
            var encodedContent = new FormUrlEncodedContent(parameters);
            Task task = client.PostAsync(URLtoken, encodedContent)
           .ContinueWith((taskwithresponse) =>
           {
               Task<string> jsonString = response.Content.ReadAsStringAsync();
               jsonString.Wait();
               rt = JsonConvert.DeserializeObject<rsAccessToken>(jsonString.Result);
           });
            task.Wait();

            client.Dispose();

            return rt;
        }

在 taskwithresponse 点捕获的响应是：

Id = 104, Status = RanToCompletion, Method = "{null}", Result = "StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:\r\n{\r\n  Connection: keep-alive\r\n  Date: Mon, 14 Sep 2020 14:41:55 GMT\r\n  ETag: W/\"789-W2Me6TSLLmO4+fEmAtfH4YWXhxs\"\r\n  Set-Cookie: TS0108eb76=0119a2687f0aa2133862c3de61eb2485030f83265a0e1bcb62403e1c777052fccfeacf2df6a14e78b161afc6a43cfc2622532765bc; Max-Age=900; Path=/\r\n  Content-Length: 1929\r\n  Content-Type: application/json; charset=utf-8\r\n}"

感谢您的帮助。

Answer 1

正确的代码是：

public rsAccessToken VeteranSignup(string Code, string State, string redirect_uri)
    {

        HttpClient client = new HttpClient();
        rsAccessToken rt = null;
        client.BaseAddress = new Uri(URLtoken);
        string grant_type = "authorization_code";

        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
        var byteArray = Encoding.ASCII.GetBytes(string.Format("{0}:{1}", clientid, secret));
        client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
        HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, URLtoken);
        var parameters = new Dictionary<string, string> { { "grant_type", grant_type }, { "code", Code }, { "state", State }, { "redirect_uri", redirect_uri } };
        var encodedContent = new FormUrlEncodedContent(parameters);
        Task task = client.PostAsync(URLtoken, encodedContent)
       .ContinueWith((taskwithresponse) =>
       {
           Task<string> jsonString = taskwithresponse.Result.Content.ReadAsStringAsync();
           jsonString.Wait();
           rt = JsonConvert.DeserializeObject<rsAccessToken>(jsonString.Result);
       });
        task.Wait();

        client.Dispose();

        return rt;
    }

Answer 2

1. 你应该使用taskwithreponse

2. 此外，您应该使用纯 aysnc 链。不要通过 aynsc 调用来同步调用。

    public async Task<rsAccessToken> Signup(string Code, string State, string redirect_uri)
    {
        using(HttpClient client = new HttpClient())
        {
           rsAccessToken rt = null;
   
           client.BaseAddress = new Uri(URLtoken);
           string grant_type = "authorization_code";
   
           client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
           var byteArray = Encoding.ASCII.GetBytes(string.Format("{0}:{1}", clientid, secret));
           client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
           var(HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, URLtoken))
           {
                 var parameters = new Dictionary<string, string> { { "grant_type", grant_type }, { "code", Code }, { "state", State }, { "redirect_uri", redirect_uri } };
                 var encodedContent = new FormUrlEncodedContent(parameters);
                 HttpResponseMessage response = await client.PostAsync(URLtoken, encodedContent)
   
                var jsonString = await response.Content.ReadAsStringAsync();
                rt = JsonConvert.DeserializeObject<rsAccessToken>(jsonString.Result);
           }
   
        return rt;
      }
    }