第一步是为HTTP客户机创建helper类。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

namespace callApi.Helpers
{
    public class CallApi
    {
        private readonly Uri BaseUrlUri;
        private HttpClient client = new HttpClient();

        public CallApi(string baseUrl)
        {
            BaseUrlUri = new Uri(baseUrl);
            client.BaseAddress = BaseUrlUri;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(
                new MediaTypeWithQualityHeaderValue("application/json"));
        }

        public HttpClient getClient()
        {
            return client;
        }

        public HttpClient getClientWithBearer(string token)
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
            return client;
        }
    }
}

然后可以在代码中使用这个类。

这是如何使用上面的类调用不带承载的REST API的示例。

// GET API/values
[HttpGet]
public async Task<ActionResult<string>> postNoBearerAsync(string email, string password,string baseUrl, string action)
{
    var request = new LoginRequest
    {
        email = email,
        password = password
    };

    var callApi = new CallApi(baseUrl);
    var client = callApi.getClient();
    HttpResponseMessage response = await client.PostAsJsonAsync(action, request);
    if (response.IsSuccessStatusCode)
        return Ok(await response.Content.ReadAsAsync<string>());
    else
        return NotFound();
}

这是一个如何调用需要承载的REST API的示例。

// GET API/values
[HttpGet]
public async Task<ActionResult<string>> getUseBearerAsync(string token, string baseUrl, string action)
{
    var callApi = new CallApi(baseUrl);
    var client = callApi.getClient();
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
    HttpResponseMessage response = await client.GetAsync(action);
    if (response.IsSuccessStatusCode)
    {
        return Ok(await response.Content.ReadAsStringAsync());
    }
    else
        return NotFound();
}

如果您想查看它如何工作的工作示例，还可以参考下面的存储库。

https://github.com/mokh223/callApi

HTTP GET请求

    string api = this.configuration["getApiUrl"];//Read from Iconfiguration object injected
     public async Task<HttpResponseMessage> GetAsync(string api, ILogger log, params dynamic[] parameters)
            {
                log.LogInformation($"Get Token");
                var token = await GetTokenAsync(this.configuration["ClientId"], this.configuration["AppKey"]).ConfigureAwait(false);
                using (var client = new HttpClient())
                {
                  client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(BearerTokenName, token);
                    var apiBaseUrl = this.configuration["BaseUrl"];
                   
                    client.BaseAddress = new Uri(apiBaseUrl);
                    var apiUrl = ConstructUrl(api, parameters);
                    var result = await client.GetAsync(apiUrl).ConfigureAwait(false);
    
                    if (result.StatusCode == System.Net.HttpStatusCode.OK)
                    {
                        return result;
                    }
                    else
                    {
                       throw new HttpResponseException(new HttpResponseMessage(result.StatusCode) { Content = new StringContent(result.ReasonPhrase) });
                    }
                }
            }
    

从HttpResponseMessage读取字符串，如下所示

     var client = await this.httpClientService.GetAsync(url, logger, Convert.ToInt32(Id, CultureInfo.InvariantCulture)).ConfigureAwait(false);
     var response = await client.Content.ReadAsStringAsync();

HTTP POST请求

     public async Task<string> PostAsync(string api, string contentValue, ILogger logger)
           {
               var token = await GetTokenAsync(this.configuration["ClientId"], this.configuration["AppKey"]).ConfigureAwait(false);
   
               using (var client = new HttpClient())
               {
                   client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(BearerTokenName, token);
                   client.BaseAddress = new Uri(resource);
                   var content = new StringContent(contentValue, Encoding.UTF8, MediaTypeNames.Application.Json);
                   var result = await client.PostAsync(new Uri(api, UriKind.Relative), content).ConfigureAwait(false);
   
                   if (result.StatusCode == System.Net.HttpStatusCode.OK)
                   {
                       return await result.Content.ReadAsStringAsync();
                   }
                   else
                   {
                       throw new HttpResponseException(new HttpResponseMessage(result.StatusCode) { Content = new StringContent(result.ReasonPhrase) });
                   }
               }
           }

    var response = await this.httpClientService.PostAsync(this.configuration["getDetails"], content, this.configuration["ApiBaseUrl"], logger).ConfigureAwait(false);
      catch (System.Web.Http.HttpResponseException httpException)
                        {
                            if (httpException.Response.StatusCode == HttpStatusCode.Unauthorized)
                            {
                                logger.LogError($"Failed To Update", httpException);
                            }
                            else
                            {
                                throw;
                            }
                        }
    return response;

在使用。net 4.5或。net Core时调用REST API

我推荐DalSoft。RestClient(注意:是我创建的)。原因是，因为它使用动态类型，您可以在一个流畅的调用中包装所有内容，包括序列化/反序列化。下面是一个工作的PUT示例:

dynamic client = new RestClient("http://jsonplaceholder.typicode.com");

var post = new Post { title = "foo", body = "bar", userId = 10 };

var result = await client.Posts(1).Put(post);

第一步是为HTTP客户机创建helper类。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

namespace callApi.Helpers
{
    public class CallApi
    {
        private readonly Uri BaseUrlUri;
        private HttpClient client = new HttpClient();

        public CallApi(string baseUrl)
        {
            BaseUrlUri = new Uri(baseUrl);
            client.BaseAddress = BaseUrlUri;
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(
                new MediaTypeWithQualityHeaderValue("application/json"));
        }

        public HttpClient getClient()
        {
            return client;
        }

        public HttpClient getClientWithBearer(string token)
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
            return client;
        }
    }
}

然后可以在代码中使用这个类。

这是如何使用上面的类调用不带承载的REST API的示例。

// GET API/values
[HttpGet]
public async Task<ActionResult<string>> postNoBearerAsync(string email, string password,string baseUrl, string action)
{
    var request = new LoginRequest
    {
        email = email,
        password = password
    };

    var callApi = new CallApi(baseUrl);
    var client = callApi.getClient();
    HttpResponseMessage response = await client.PostAsJsonAsync(action, request);
    if (response.IsSuccessStatusCode)
        return Ok(await response.Content.ReadAsAsync<string>());
    else
        return NotFound();
}

这是一个如何调用需要承载的REST API的示例。

// GET API/values
[HttpGet]
public async Task<ActionResult<string>> getUseBearerAsync(string token, string baseUrl, string action)
{
    var callApi = new CallApi(baseUrl);
    var client = callApi.getClient();
    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
    HttpResponseMessage response = await client.GetAsync(action);
    if (response.IsSuccessStatusCode)
    {
        return Ok(await response.Content.ReadAsStringAsync());
    }
    else
        return NotFound();
}

如果您想查看它如何工作的工作示例，还可以参考下面的存储库。

https://github.com/mokh223/callApi

    var TakingRequset = WebRequest.Create("http://xxx.acv.com/MethodName/Get");
    TakingRequset.Method = "POST";
    TakingRequset.ContentType = "text/xml;charset=utf-8";
    TakingRequset.PreAuthenticate = true;

    //---Serving Request path query
     var PAQ = TakingRequset.RequestUri.PathAndQuery;

    //---creating your xml as per the host reqirement
    string xmlroot=@"<root><childnodes>passing parameters</childnodes></root>";
    string xmlroot2=@"<root><childnodes>passing parameters</childnodes></root>";

    //---Adding Headers as requested by host 
    xmlroot2 = (xmlroot2 + "XXX---");
    //---Adding Headers Value as requested by host 
  //  var RequestheaderVales = Method(xmlroot2);

    WebProxy proxy = new WebProxy("XXXXX-----llll", 8080);
    proxy.Credentials = new NetworkCredential("XXX---uuuu", "XXX----", "XXXX----");
    System.Net.WebRequest.DefaultWebProxy = proxy;


    // Adding The Request into Headers
    TakingRequset.Headers.Add("xxx", "Any Request Variable ");
    TakingRequset.Headers.Add("xxx", "Any Request Variable");

    byte[] byteData = Encoding.UTF8.GetBytes(xmlroot);
    TakingRequset.ContentLength = byteData.Length;

    using (Stream postStream = TakingRequset.GetRequestStream())
    {
        postStream.Write(byteData, 0, byteData.Length);
        postStream.Close();
    }



    StreamReader stredr = new StreamReader(TakingRequset.GetResponse().GetResponseStream());
    string response = stredr.ReadToEnd();

我使用Web API 2.0以这种简单的方式做到了这一点。您可以删除UseDefaultCredentials。我在自己的用例中使用了它。

List<YourObject> listObjects = new List<YourObject>();

string response = "";
using (var client = new WebClient() { UseDefaultCredentials = true })
{
     response = client.DownloadString(apiUrl);
}

listObjects = JsonConvert.DeserializeObject<List<YourObject>>(response);
return listObjects;