如何使用 HTTP POST 从 C# 调用 Web 服务

Question

我想编写 c# 类，该类将创建与运行到 www.temp.com 的 Web 服务的连接，将 2 个字符串参数发送到方法 DoSomething 并获取字符串结果。 我不想使用 wsdl。因为我知道网络服务的参数，所以我只想进行一个简单的调用。

我想在 .Net 2 中应该有一个简单的方法来做到这一点，但我找不到任何例子......

Answer 1

如果此“webservice”是简单的 HTTP GET，则可以使用 WebRequest ：

WebRequest request = WebRequest.Create("http://www.temp.com/?param1=x¶m2=y");
request.Method="GET";
WebResponse response = request.GetResponse();

从那里您可以查看 response.GetResponseStream 用于输出。您可以用同样的方式访问 POST 服务。

然而，如果这是一个 SOAP Web 服务，那就没那么容易了。根据 Web 服务的安全性和选项，有时您可以采用已形成的请求并将其用作模板 - 替换参数值并发送它（使用 Webrequest），然后手动解析 SOAP 响应...但在这种情况下您正在考虑大量额外的工作，不妨使用 wsdl.exe 来生成代理。

Answer 2

我将探索如何将 ASP.NET MVC 用于您的 Web 服务。您可以通过标准表单参数提供参数并以 JSON 形式返回结果。

[HttpPost]
public ActionResult MyPostAction( string foo, string bar )
{
     ...
     return Json( new { Value = "baz" } );
}

HttpWebRequest

var request = WebRequest.Create( "/controller/mypostaction" );
request.Method = "POST";
var data = string.Format( "foo={0}&bar={1}", foo, bar );
using (var writer = new StreamWriter( request.GetRequestStream() ))
{
    writer.WriteLine( data );
}
var response = request.GetResponse();
var serializer = new DataContractJsonSerializer(typeof(PostActionResult));
var result = serializer.ReadObject( response.GetResponseStream() )
                 as PostActionResult;

在您的客户端中，使用您拥有的

public class PostActionResult
{
     public string Value { get; set; }
}

Answer 3

另一种调用 POST 方法的方法是，我曾经在 WebAPI 中调用 POST 方法。

            WebClient wc = new WebClient();

            string result;
            wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
            result = wc.UploadString("http://localhost:23369/MyController/PostMethodName/Param 1/Param 2","");

            Response.Write(result);

Answer 4

您可以使用 Newtonsoft.Json 返回 List 对象：

WebClient wc = new WebClient();
  string result;
  wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
  var data = string.Format("Value1={0}&Value2={1}&Value3={2}", "param1", "param2", "param3");
  result = wc.UploadString("http:your_services", data);
  var ser = new JavaScriptSerializer();
  var people = ser.Deserialize<object_your[]>(result);

Answer 5

这是一个无需凭据即可调用任何服务的静态方法

    /// <summary>
    ///     Connect to service without credentials
    /// </summary>
    /// <param name="url">string url</param>
    /// <param name="requestType">type of request</param>
    /// <param name="objectResult">expected success object result</param>
    /// <param name="objectErrorResult">expected error object result</param>
    /// <param name="objectErrorResultDescription">expected error object description</param>
    /// <param name="body">request body</param>
    /// <param name="bodyType">type of body</param>
    /// <param name="parameters">parameters of request</param>
    /// <returns></returns>
    public static object ConnectToService(string url, string model, RequestType requestType, string objectResult, string objectErrorResult,
                                                      string objectErrorResultDescription, string body = null, string bodyType = null,
                                                      string parameters = null)
    {
        try
        {
            HttpClient client = new HttpClient();
            string tokenEndpoint = url;
            StringContent stringContent;
            string result = string.Empty;

            switch (requestType)
            {
                case RequestType.Get:
                    {
                        var returnRequest = client.GetAsync(tokenEndpoint).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Post:
                    {
                        stringContent = new StringContent(body, Encoding.UTF8, bodyType);

                        var returnRequest = client.PostAsync(tokenEndpoint, stringContent).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Put:
                    {
                        stringContent = new StringContent(body, Encoding.UTF8, bodyType);

                        var returnRequest = client.PutAsync(tokenEndpoint, stringContent).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Delete:
                    {
                        var returnRequest = client.DeleteAsync(tokenEndpoint).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                default:
                    break;
            }

            JObject jobject = !string.IsNullOrEmpty(result) ? JObject.Parse(result) : null;
            var obj = jobject != null ? (jobject[objectResult]?.ToList()?.Count > 0 ? jobject[objectResult]?.ToList() : null) : null;

            return (obj == null && jobject?.ToString() == null && jobject[objectResult]?.ToString() == null) ? throw new Exception(($"{jobject[objectErrorResult]?.ToString()} - {jobject[objectErrorResultDescription]?.ToString()}") ?? (new { Error = new { Code = 400, Message = $"{model} - Requisição inválida." } }).ToString()) : (obj ?? (object)jobject[objectResult]?.ToString()) == null ? jobject : (obj ?? (object)jobject[objectResult]?.ToString());
        }
        catch (NullReferenceException)
        {
            return null;
        }
        catch (Exception e)
        {
            throw new Exception($"{model} - Requisição inválida. Detalhes: {e.Message ?? e.InnerException.Message}");
        }
    }

这是一个可使用凭据来调用任何服务的静态方法

    /// <summary>
    ///     Connect to service with credentials
    /// </summary>
    /// <param name="url">string url</param>
    /// <param name="requestType">type of request</param>
    /// <param name="handler">credentials</param>
    /// <param name="objectResult">expected success object result</param>
    /// <param name="objectErrorResult">expected error object result</param>
    /// <param name="objectErrorResultDescription">expected error object description</param>
    /// <param name="body">request body</param>
    /// <param name="bodyType">type of body</param>
    /// <param name="parameters">parameters of request</param>
    /// <returns></returns>
    public static object ConnectToService(string url, string model, RequestType requestType, HttpClientHandler handler, string objectResult, string objectErrorResult,
                                                      string objectErrorResultDescription, string body = null, string bodyType = null,
                                                      string parameters = null)
    {
        try
        {
            HttpClient client = new HttpClient(handler);
            string tokenEndpoint = url;
            StringContent stringContent;
            string result = string.Empty;

            switch (requestType)
            {
                case RequestType.Get:
                    {
                        var returnRequest = client.GetAsync(tokenEndpoint).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Post:
                    {
                        stringContent = new StringContent(body, Encoding.UTF8, bodyType);

                        var returnRequest = client.PostAsync(tokenEndpoint, stringContent).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Put:
                    {
                        stringContent = new StringContent(body, Encoding.UTF8, bodyType);

                        var returnRequest = client.PutAsync(tokenEndpoint, stringContent).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                case RequestType.Delete:
                    {
                        var returnRequest = client.DeleteAsync(tokenEndpoint).Result;
                        result = returnRequest.Content.ReadAsStringAsync().Result;

                        break;
                    }
                default:
                    break;
            }

            JObject jobject = !string.IsNullOrEmpty(result) ? JObject.Parse(result) : null;
            var obj = jobject != null ? (jobject[objectResult]?.ToList()?.Count > 0 ? jobject[objectResult]?.ToList() : null) : null;

            return (obj == null && jobject?.ToString() == null && jobject[objectResult]?.ToString() == null) ? throw new Exception(($"{jobject[objectErrorResult]?.ToString()} - {jobject[objectErrorResultDescription]?.ToString()}") ?? (new { Error = new { Code = 400, Message = $"{model} - Requisição inválida." } }).ToString()) : (obj ?? (object)jobject[objectResult]?.ToString()) == null ? jobject : (obj ?? (object)jobject[objectResult]?.ToString());
        }
        catch (NullReferenceException)
        {
            return null;
        }
        catch (Exception e)
        {
            throw new Exception($"{model} - Invalid request. {e.Message.Split(',')[0] ?? e.InnerException.Message.Split(',')[0]}");
        }
    }