IHttpClientFactory是什么？为什么出现了IHttpClientFactory
一、IHttpClientFactory是什么？
IHttpClientFactory是.netcore2.1才开始引入的，是HttpClient的工厂接口，它为我们提供了获取HttpClient的接口，它帮助我们维护HttpClient的生命周期。当我们需要HttpClient访问网络时，它会自动帮我们获取或者是创建HttpClient（存在空闲的HttpClient时，直接提供；当不存在可用的HttpClient时自动创建）。它相当于HttpClient池。
二、为什么出现IHttpClientFactory？
传统的HttpClient创建后，其占用了Socket资源并且其不会是及时的回收。我们每次new一个HttpClient时是一个全新的对象，所以在高并发下又是会导致socket资源耗尽（Unable to connect to the remote serverSystem.Net.Sockets.SocketException: Only one usage of each socket address (protocol/network address/port) is normally permitted.）。而如果采用单例或者静态的HttpClient，却达不到高效的使用网络请求，而且当访问不同的url时，单例或者静态的HttpClient往往会导致访问混乱而出现错误。
.NetCore简单封装基于IHttpClientFactory的HttpClient请求
1 public class HttpWebClient
2 {
3
4 private IHttpClientFactory _httpClientFactory;
5 public HttpWebClient(IHttpClientFactory httpClientFactory)
6 {
7 this._httpClientFactory = httpClientFactory;
8 }
9 /// <summary>
10 /// Get请求
11 /// </summary>
12 /// <param name="url"></param>
13 /// <param name="dicHeaders"></param>
14 /// <param name="timeoutSecond"></param>
15 /// <returns></returns>
16 //public async Task<string> GetAsync(string url, int timeoutSecond = 120)
17 //{
18 // var client = _httpClientFactory.CreateClient();
19 // #region 最好不要这样绑定header，
20 // //DefaultRequestHeaders是和httpClient绑定的，当完成当前请求后，其它请求从factory中获取时，还是会有绑定的header的
21 // //会造成错误
22 // //if (dicHeaders != null)
23 // //{
24 // // foreach (var header in dicHeaders)
25 // // {
26 // // client.DefaultRequestHeaders.Add(header.Key, header.Value);
27 // // }
28 // //}
29 // #endregion
30 // client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
31 // var response = await client.GetAsync(url);
32 // var result = await response.Content.ReadAsStringAsync();
33 // return result;
34 //}
35
36
37
38
39 /// <summary>
40 /// Get异步请求
41 /// </summary>
42 /// <param name="url"></param>
43 /// <param name="dicHeaders"></param>
44 /// <param name="timeoutSecond"></param>
45 /// <returns></returns>
46 public async Task<string> GetAsync(string url, Dictionary<string, string> dicHeaders, int timeoutSecond = 120)
47 {
48 var client = _httpClientFactory.CreateClient();
49 var request = new HttpRequestMessage(HttpMethod.Get, url);
50 if (dicHeaders != null)
51 {
52 foreach (var header in dicHeaders)
53 {
54 request.Headers.Add(header.Key, header.Value);
55 }
56 }
57 client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
58 var response = await client.SendAsync(request);
59 if (response.IsSuccessStatusCode)
60 {
61 var result = await response.Content.ReadAsStringAsync();
62 return result;
63 }
64 else
65 {
66 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
67
68 }
69 }
70 /// <summary>
71 ///
72 /// </summary>
73 /// <param name="url"></param>
74 /// <param name="requestString"></param>
75 /// <param name="dicHeaders"></param>
76 /// <param name="timeoutSecond"></param>
77 /// <returns></returns>
78 public async Task<string> PostAsync(string url, string requestString, Dictionary<string, string> dicHeaders, int timeoutSecond)
79 {
80 var client = _httpClientFactory.CreateClient();
81 var requestContent = new StringContent(requestString);
82 if (dicHeaders != null)
83 {
84 foreach (var head in dicHeaders)
85 {
86 requestContent.Headers.Add(head.Key, head.Value);
87 }
88 }
89 client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
90 var response = await client.PostAsync(url, requestContent);
91 if (response.IsSuccessStatusCode)
92 {
93 var result = await response.Content.ReadAsStringAsync();
94 return result;
95 }
96 else
97 {
98 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
99 }
100 }
101 /// <summary>
102 ///
103 /// </summary>
104 /// <param name="url"></param>
105 /// <param name="requestString"></param>
106 /// <param name="dicHeaders"></param>
107 /// <param name="timeoutSecond"></param>
108 /// <returns></returns>
109 public async Task<string> PutAsync(string url, string requestString, Dictionary<string, string> dicHeaders, int timeoutSecond)
110 {
111 var client = _httpClientFactory.CreateClient();
112 var requestContent = new StringContent(requestString);
113 if (dicHeaders != null)
114 {
115 foreach (var head in dicHeaders)
116 {
117 requestContent.Headers.Add(head.Key, head.Value);
118 }
119 }
120 client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
121 var response = await client.PutAsync(url, requestContent);
122 if (response.IsSuccessStatusCode)
123 {
124 var result = await response.Content.ReadAsStringAsync();
125 return result;
126 }
127 else
128 {
129 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
130 }
131 }
132
133 /// <summary>
134 /// Patch异步请求
135 /// </summary>
136 /// <param name="url"></param>
137 /// <param name="requestString"></param>
138 /// <param name="dicHeaders"></param>
139 /// <param name="timeoutSecond"></param>
140 /// <returns></returns>
141 public async Task<string> PatchAsync(string url, string requestString, Dictionary<string, string> dicHeaders, int timeoutSecond)
142 {
143 var client = _httpClientFactory.CreateClient();
144 var requestContent = new StringContent(requestString);
145 if (dicHeaders != null)
146 {
147 foreach (var head in dicHeaders)
148 {
149 requestContent.Headers.Add(head.Key, head.Value);
150 }
151 }
152 client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
153 var response = await client.PatchAsync(url, requestContent);
154 if (response.IsSuccessStatusCode)
155 {
156 var result = await response.Content.ReadAsStringAsync();
157 return result;
158 }
159 else
160 {
161 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
162 }
163 }
164 public async Task<string> DeleteAsync(string url, Dictionary<string, string> dicHeaders, int timeoutSecond)
165 {
166 var client = _httpClientFactory.CreateClient();
167 var request = new HttpRequestMessage(HttpMethod.Delete, url);
168 if (dicHeaders != null)
169 {
170 foreach (var head in dicHeaders)
171 {
172 request.Headers.Add(head.Key, head.Value);
173 }
174 }
175 client.Timeout = TimeSpan.FromSeconds(timeoutSecond);
176 var response = await client.SendAsync(request);
177 if (response.IsSuccessStatusCode)
178 {
179 var result = await response.Content.ReadAsStringAsync();
180 return result;
181 }
182 else
183 {
184 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
185 }
186 }
187 /// <summary>
188 /// 异步请求（通用）
189 /// </summary>
190 /// <param name="url"></param>
191 /// <param name="method"></param>
192 /// <param name="requestString"></param>
193 /// <param name="dicHeaders"></param>
194 /// <param name="timeoutSecond"></param>
195 /// <returns></returns>
196 public async Task<string> ExecuteAsync(string url, HttpMethod method, string requestString, Dictionary<string, string> dicHeaders, int timeoutSecond = 120)
197 {
198 var client = _httpClientFactory.CreateClient();
199 var request = new HttpRequestMessage(method, url)
200 {
201 Content = new StringContent(requestString),
202 };
203 if (dicHeaders != null)
204 {
205 foreach (var header in dicHeaders)
206 {
207 request.Headers.Add(header.Key, header.Value);
208 }
209 }
210 var response = await client.SendAsync(request);
211 if (response.IsSuccessStatusCode)
212 {
213 var result = await response.Content.ReadAsStringAsync();
214 return result;
215 }
216 else
217 {
218 throw new CustomerHttpException($"接口请求错误,错误代码{response.StatusCode}，错误原因{response.ReasonPhrase}");
219 }
220 }
221
222 }
CustomerHttpException类的简单定义
public class CustomerHttpException : Exception
{
public CustomerHttpException() : base()
{ }
public CustomerHttpException(string message) : base(message)
{ }
}