如何使用C＃调用REST api？

本文翻译自：How do I make calls to a REST api using C#?

This is the code I have so far: 这是我到目前为止的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System;
using System.Net.Http;
using System.Web;
using System.Net;
using System.IO;

namespace ConsoleProgram
{
    public class Class1
    {
        private const string URL = "https://sub.domain.com/objects.json?api_key=123";
        private const string DATA = @"{""object"":{""name"":""Name""}}";

        static void Main(string[] args)
        {
            Class1.CreateObject();
        }

        private static void CreateObject()
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
            request.Method = "POST";
            request.ContentType = "application/json"; 
            request.ContentLength = DATA.Length;
            StreamWriter requestWriter = new StreamWriter(request.GetRequestStream(), System.Text.Encoding.ASCII);
            requestWriter.Write(DATA);
            requestWriter.Close();

             try {
                WebResponse webResponse = request.GetResponse();
                Stream webStream = webResponse.GetResponseStream();
                StreamReader responseReader = new StreamReader(webStream);
                string response = responseReader.ReadToEnd();
                Console.Out.WriteLine(response);
                responseReader.Close();
            } catch (Exception e) {
                Console.Out.WriteLine("-----------------");
                Console.Out.WriteLine(e.Message);
            }

        }
    }
}

The problem is that I think the exception block is being triggered (because when I remove the try-catch, I get a server error (500) message. But I don't see the Console.Out lines I put in the catch block. 问题是我认为异常块正在触发（因为当我删除try-catch时，会收到服务器错误（500）消息。但是我看不到放置在catch块中的Console.Out行。

My Console: 我的控制台：

The thread 'vshost.NotifyLoad' (0x1a20) has exited with code 0 (0x0).
The thread '' (0x1988) has exited with code 0 (0x0).
The thread 'vshost.LoadReference' (0x1710) has exited with code 0 (0x0).
'ConsoleApplication1.vshost.exe' (Managed (v4.0.30319)): Loaded 'c:\users\l. preston sego iii\documents\visual studio 11\Projects\ConsoleApplication1\ConsoleApplication1\bin\Debug\ConsoleApplication1.exe', Symbols loaded.
'ConsoleApplication1.vshost.exe' (Managed (v4.0.30319)): Loaded 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll', Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
A first chance exception of type 'System.Net.WebException' occurred in System.dll
The thread 'vshost.RunParkingWindow' (0x184c) has exited with code 0 (0x0).
The thread '' (0x1810) has exited with code 0 (0x0).
The program '[2780] ConsoleApplication1.vshost.exe: Program Trace' has exited with code 0 (0x0).
The program '[2780] ConsoleApplication1.vshost.exe: Managed (v4.0.30319)' has exited with code 0 (0x0).

I'm using Visual Studio 2011 Beta, and .NET 4.5 Beta. 我正在使用Visual Studio 2011 Beta和.NET 4.5 Beta。

---

#1楼

参考：https://stackoom.com/question/eMfm/如何使用C-调用REST-api

---

#2楼

The ASP.Net Web API has replaced the WCF Web API previously mentioned. ASP.Net Web API取代了前面提到的WCF Web API。

I thought I'd post an updated answer since most of these responses are from early 2012, and this thread is one of the top results when doing a Google search for "call restful service c#". 我想我应该发布更新的答案，因为这些回复大多数都来自2012年初，而该线程是在Google搜索“呼叫宁静的服务c＃”时的最佳结果之一。

Current guidance from Microsoft is to use the Microsoft ASP.NET Web API Client Libraries to consume a RESTful service. Microsoft当前的指南是使用Microsoft ASP.NET Web API客户端库来使用RESTful服务。 This is available as a NuGet package, Microsoft.AspNet.WebApi.Client. 它可以作为NuGet包Microsoft.AspNet.WebApi.Client使用。 You will need to add this NuGet package to your solution. 您将需要将此NuGet软件包添加到您的解决方案中。

Here's how your example would look when implemented using the ASP.Net Web API Client Library: 使用ASP.Net Web API客户端库实现时，示例如下所示：

using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers; 

namespace ConsoleProgram
{
    public class DataObject
    {
        public string Name { get; set; }
    }

    public class Class1
    {
        private const string URL = "https://sub.domain.com/objects.json";
        private string urlParameters = "?api_key=123";

        static void Main(string[] args)
        {
            HttpClient client = new HttpClient();
            client.BaseAddress = new Uri(URL);

            // Add an Accept header for JSON format.
            client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/json"));

            // List data response.
            HttpResponseMessage response = client.GetAsync(urlParameters).Result;  // Blocking call! Program will wait here until a response is received or a timeout occurs.
            if (response.IsSuccessStatusCode)
            {
                // Parse the response body.
                var dataObjects = response.Content.ReadAsAsync>().Result;  //Make sure to add a reference to System.Net.Http.Formatting.dll
                foreach (var d in dataObjects)
                {
                    Console.WriteLine("{0}", d.Name);
                }
            }
            else
            {
                Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
            }

            //Make any other calls using HttpClient here.

            //Dispose once all HttpClient calls are complete. This is not necessary if the containing object will be disposed of; for example in this case the HttpClient instance will be disposed automatically when the application terminates so the following call is superfluous.
            client.Dispose();
        }
    }
}

If you plan on making multiple requests, you should re-use your HttpClient instance. 如果计划发出多个请求，则应重新使用HttpClient实例。 See this question and its answers for more details on why a using statement was not used on the HttpClient instance in this case: Do HttpClient and HttpClientHandler have to be disposed? 有关为什么在这种情况下HttpClient实例上不使用using语句的更多详细信息，请参见此问题及其答案： 是否必须处置HttpClient和HttpClientHandler？

For more details, including other examples, go here: http://www.asp.net/web-api/overview/web-api-clients/calling-a-web-api-from-a-net-client 有关更多详细信息，包括其他示例，请转到此处： http : //www.asp.net/web-api/overview/web-api-clients/calling-a-web-api-from-a-net-client

This blog post may also be useful: http://johnnycode.com/2012/02/23/consuming-your-own-asp-net-web-api-rest-service/ 该博客文章也可能有用： http : //johnnycode.com/2012/02/23/consumption-your-own-asp-net-web-api-rest-service/

---

#3楼

    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=@"passing parameters";
    string xmlroot2=@"passing parameters";

    //---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();

---

#4楼

Please use below code for your REST api request 请对您的REST API请求使用以下代码

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Json;

namespace ConsoleApplication2
{
    class Program
    {
        private const string URL = "https://XXXX/rest/api/2/component";
        private const string DATA = @"{
    ""name"": ""Component 2"",
    ""description"": ""This is a JIRA component"",
    ""leadUserName"": ""xx"",
    ""assigneeType"": ""PROJECT_LEAD"",
    ""isAssigneeTypeValid"": false,
    ""project"": ""TP""}";

        static void Main(string[] args)
        {
            AddComponent();
        }

        private static void AddComponent()
        {
            System.Net.Http.HttpClient client = new System.Net.Http.HttpClient();
            client.BaseAddress = new System.Uri(URL);
            byte[] cred = UTF8Encoding.UTF8.GetBytes("username:password");
            client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(cred));
            client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));

            System.Net.Http.HttpContent content = new StringContent(DATA, UTF8Encoding.UTF8, "application/json");
            HttpResponseMessage messge = client.PostAsync(URL, content).Result;
            string description = string.Empty;
            if (messge.IsSuccessStatusCode)
            {
                string result = messge.Content.ReadAsStringAsync().Result;
                description = result;
            }
        }
    }
}

---

#5楼

This is an example code that works for sure. 这是可以肯定起作用的示例代码。 It took me a day to make this to read a set of object from Rest service: 我花了一天的时间才能从Rest服务中读取一组对象：

RootObject is the type of the object Im reading from the rest service. RootObject是Im从其余服务读取的对象的类型。

string url = @"http://restcountries.eu/rest/v1";
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(IEnumerable));
WebClient syncClient = new WebClient();
string content = syncClient.DownloadString(url);

using (MemoryStream memo = new MemoryStream(Encoding.Unicode.GetBytes(content)))
{
    IEnumerable countries = (IEnumerable)serializer.ReadObject(memo);    
}

Console.Read();

---

#6楼

Update for calling a REST API when using .NET 4.5 or .NET Core 使用.NET 4.5或.NET Core时用于调用REST API的更新

I would suggest DalSoft.RestClient (caveat I created it). 我建议DalSoft.RestClient （我创建它的腔 ）。 The reason being because it uses dynamic typing you can wrap everything up in one fluent call including serialization/de-serialization. 原因是因为它使用动态类型，所以您可以将所有内容包装在一个流畅的调用中，包括序列化/反序列化。 Below is a working PUT example: 以下是一个有效的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);