C# HttpClient 请求认证、数据传输笔记
<p>C# HttpClient 请求认证、数据传输笔记</p><p></p><div class="toc"><div class="toc-container-header">目录</div><ul><li>一，授权认证<ul><li><ul><li>1. 基础认证示例</li><li>2. JWT 认证示例</li><li>3. Cookie 示例</li></ul></li></ul></li><li>二，请求类型</li><li>三，数据传输<ul><li><ul><li>1. Query</li><li>2. Header</li><li>3. 表单</li><li>4. JSON</li><li>5. 上传文件</li></ul></li></ul></li></ul></div><p></p>
<h2 id="一授权认证">一，授权认证</h2>
<p>客户端请求服务器时，需要通过授权认证许可，方能获取服务器资源，目前比较常见的认证方式有 Basic 、JWT、Cookie。</p>
<p>HttpClient 是 C# 中的 HTTP/HTTPS 客户端，用于发送 HTTP 请求和接收来自通过 URI 确认的资源的 HTTP 响应。下面以具体代码做示范。</p>
<h4 id="1-基础认证示例">1. 基础认证示例</h4>
<pre><code class="language-c#"> // Basic基础认证
public async Task Basic(string user, string password, string url)
{
// 如果认证页面是 https 的，请参考一下 jwt 认证的 HttpClientHandler
// 创建client
HttpClient client = new HttpClient();
// 创建身份认证
// using System.Net.Http.Headers;
AuthenticationHeaderValue authentication = new AuthenticationHeaderValue(
"Basic",
Convert.ToBase64String(Encoding.UTF8.GetBytes($"{user}:{password}")
));
client.DefaultRequestHeaders.Authorization = authentication;
byte[] response = await client.GetByteArrayAsync(url);
client.Dispose();
}
</code></pre>
<p>可以看到 Basic 认证的安全程度非常低，多用于路由器和嵌入式设备，而且往往不会使用 HTTPS。</p>
<h4 id="2-jwt-认证示例">2. JWT 认证示例</h4>
<pre><code class="language-c#"> // Jwt认证
public async Task Bearer(string token, string url)
{
// HttpClientHandler及其派生类使开发人员能够配置各种选项, 包括从代理到身份验证。
// helpLink https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpclienthandler?view=netframework-4.8
var httpclientHandler = new HttpClientHandler();
// 如果服务器有 https 证书，但是证书不安全，则需要使用下面语句
// => 也就是说，不校验证书，直接允许
httpclientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true;
using (var httpClient = new HttpClient(httpclientHandler))
{
// 创建身份认证
// System.Net.Http.Headers.AuthenticationHeaderValue;
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
await httpClient.GetAsync(url);
httpClient.Dispose();
}
}
</code></pre>
<p>JWT 认证，需要客户端携带 token ，token 是一段加密过的字符串，关于原理这里不多说，token 是通过客户端 header 携带的。</p>
<p>另外，对于测试的 Web 应用或者内网应用， HTTPS 证书可能不是公网国际认证的证书，就需要跳过认证，直接允许访问使用。</p>
<pre><code class="language-c#"> var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
};
</code></pre>
<h4 id="3-cookie-示例">3. Cookie 示例</h4>
<p>HttpClient 中，Cookie 有两种处理方式。</p>
<p>一种是已经知道 Cookie ，直接将 Cookie 存储到 HttpClient 中；另一种是还没有 Cookie ，通过账号密码登录获取到 Cookie ，自动存储到 HttpClient 对象中，接着使用当前 HttpClient 对象请求 URL。</p>
<p>两种方式的设定，是通过 HttpClientHandler 的 UseCookies 属性设置的。</p>
<p>示例</p>
<pre><code class="language-c#"> var httpclientHandler = new HttpClientHandler()
{
UseCookies = true
};
</code></pre>
<p> UseCookies 获取或设置一个值，该值指示处理程序是否使用 CookieContainer 属性存储服务器 Cookie，并在发送请求时使用这些 Cookie。</p>
<p>方式1：</p>
<pre><code class="language-c#"> // 先用账号密码登陆再请求
public async Task Cookie(string user, string password, string loginUrl, string url)
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
UseCookies = true
};
// 如果服务器有 https 证书，但是证书不安全，则需要使用下面语句
// => 也就是说，不校验证书，直接允许
var loginContent = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string,string>("user",user),
new KeyValuePair<string, string>("password",password)
});
using (var httpClient = new HttpClient(httpclientHandler))
{
// 先登陆
var result = await httpClient.PostAsync(loginUrl, loginContent);
// 登陆成功后，客户端会自动携带 cookie ，不需要再手动添加
//if (result.IsSuccessStatusCode)
//{
// /*
// * 如果请求成功
// */
//}
var result2 = await httpClient.GetAsync(url);
// httpclient 已经携带 Cookie ，可以多次使用
// var result3 = await httpClient.GetAsync(url3);
// var result4 = await httpClient.GetAsync(url4);
httpClient.Dispose();
}
}
</code></pre>
<p>方式2：</p>
<pre><code class="language-c#"> //已经拿到 cookie ，直接使用 cookie 请求
public async Task Cookie(string cookie, string url)
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
UseCookies = false
};
// 如果服务器有 https 证书，但是证书不安全，则需要使用下面语句
// => 也就是说，不校验证书，直接允许
using (var httpClient = new HttpClient(httpclientHandler))
{
httpClient.DefaultRequestHeaders.Add("Cookie", cookie);
await httpClient.GetAsync(url);
httpClient.Dispose();
}
}
</code></pre>
<h2 id="二请求类型">二，请求类型</h2>
<p>HTTP 请求里，有 GET、POST、DELETE、PUT 等请求方式。</p>
<p>HttpClient 中，有以下请求相关的方法</p>
<ol>
<li>CancelPendingRequests</li>
<li>DeleteAsync</li>
<li>GetAsync</li>
<li>GetByteArrayAsync</li>
<li>GetStreamAsync</li>
<li>GetStringAsync</li>
<li>PostAsync</li>
<li>PutAsync</li>
<li>SendAsync</li>
</ol>
<p>其中， CancelPendingRequests 是取消该实例所有挂起的请求，不是请求类型。</p>
<p>SendAsync 用于处理送 HttpRequestMessage(表示一条 HTTP 请求消息)，比较原生。</p>
<p><img src="https://img2018.cnblogs.com/blog/1315495/201910/1315495-20191011202239404-1456868843.jpg" alt="s" loading="lazy"></p>
<p>对于 GetAsync、PostAsync等请求方法，使用过程类似，下面是使用示例</p>
<pre><code class="language-c#"> public async void Request(string url)
{
using (var httpClient = new HttpClient())
{
// HttpClient 中，所有 Get 请求都是异步的
HttpResponseMessage result = await httpClient.GetAsync(url);
// Task<>.Result 可以获取异步结果
result = httpClient.GetAsync(url).Result;
//var result1 = await httpClient.GetByteArrayAsync(url);
//var result1 = await httpClient.GetStreamAsync(url);
//var result1 = await httpClient.GetStringAsync(url);
// ByteArrayContent
FormUrlEncodedContent fromContent = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string,string>("Email","123@qq.com"),
new KeyValuePair<string, string>("Number","666")
});
// 使用 Post ，必须携带 继承 HttpContent 的对象
// 就是说，Post 必须要上传数据
result = await httpClient.PostAsync(url, fromContent);
// 如果没有数据要上传，可以使用 null
result = await httpClient.PostAsync(url, null);
httpClient.Dispose();
}
</code></pre>
<h2 id="三数据传输">三，数据传输</h2>
<p>HTTP/HTTPS 请求中，往往随着数据传输，例如表单提交、JSON上传、文件上传等，下面以代码示范。</p>
<h4 id="1-query">1. Query</h4>
<p>ASP.NET Core API 可以这样写</p>
<pre><code class="language-c#">
public async Task<JsonResult> AAA(int? a, int? b)
{
if (a == null || b == null)
return new JsonResult(new { code = 0, result = "aaaaaaaa" });
return new JsonResult(new { code = 2000, result = a + "|" + b });
}
</code></pre>
<p>HttpClient</p>
<pre><code class="language-c#"> // URL Query 参数
public void Query(string a, string b)
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
};
using (var httpClient = new HttpClient(httpclientHandler))
{
var result = httpClient.PostAsync($"https://localhost:5001/test?a={a}&b={b}", null).Result;
httpClient.Dispose();
}
}
</code></pre>
<h4 id="2-header">2. Header</h4>
<p>Header 是以键值形式存储的，HttpClient 示例</p>
<pre><code class="language-c#"> // Header 头
public void Header()
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
};
using (var httpClient = new HttpClient(httpclientHandler))
{
httpClient.DefaultRequestHeaders.Add("MyEmail", "123@qq.com");
var result = httpClient.GetAsync($"https://localhost:5001/test").Result;
httpClient.Dispose();
}
}
</code></pre>
<p>ASP.NET Core API 示例</p>
<pre><code class="language-c#">
public async Task<JsonResult> DDD(int? a, int? b)
{
if (a == null || b == null)
return new JsonResult(new { code = 0, result = "aaaaaaaa" });
return new JsonResult(new { code = 200, result = a + "|" + b });
}
</code></pre>
<h4 id="3-表单">3. 表单</h4>
<pre><code class="language-c#"> //表单提交
// application/x-www-form-urlencoded
public void From()
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
};
var fromContent = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string,string>("Id","1"),
new KeyValuePair<string,string>("Name","痴者工良"),
new KeyValuePair<string, string>("Number","666666")
});
using (var httpClient = new HttpClient(httpclientHandler))
{
var result = httpClient.PostAsync("https://localhost:5001/test", fromContent).Result;
Console.WriteLine(result.Content.ReadAsStringAsync().Result);
httpClient.Dispose();
}
}
</code></pre>
<h4 id="4-json">4. JSON</h4>
<p>除了 JSON ，还有</p>
<ul>
<li>text/html<br>
application/javascript<br>
text/plain<br>
application/xml</li>
</ul>
<p>他们都是使用 StringContent 来表示。</p>
<pre><code class="language-c#"> // Json 等
public void StringAnd(string json)
{
var httpclientHandler = new HttpClientHandler()
{
ServerCertificateCustomValidationCallback = (message, cert, chain, error) => true,
};
var jsonContent = new StringContent(json);
// Json 是 StringContent，上传时要指定 Content-Type 属性，除此外还有
// text/html
// application/javascript
// text/plain
// application/xml
jsonContent.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");
using (var httpClient = new HttpClient(httpclientHandler))
{
var result = httpClient.PostAsync("https://localhost:5001/test", jsonContent).Result;
Console.WriteLine(result.Content.ReadAsStringAsync().Result);
httpClient.Dispose();
}
}
</code></pre>
<h4 id="5-上传文件">5. 上传文件</h4>
<p>API 这样写</p>
<pre><code class="language-c#"> //上传文件是 post 方式，这里加不加都可以
public async Task<IActionResult> UploadFiles(List<IFormFile> files)
{
// ...
}
</code></pre>
<p>HttpClient 写法</p>
<pre><code class="language-c#"> // 上传文件
public async Task File(string filepath, string fromName, string url)
{
using (var client = new HttpClient())
{
FileStream imagestream = System.IO.File.OpenRead(filepath);
// multipartFormDataContent.Add();
var multipartFormDataContent = new MultipartFormDataContent()
{
{
new ByteArrayContent(System.IO.File.ReadAllBytes(filepath)), // 文件流
fromName, // 对应 服务器 WebAPI 的传入参数
Path.GetFileName(filepath) // 上传的文件名称
}
};
/*
* 如果服务器 API 写法是
* (IFromFile files)
* 那么上面的 fromName="files"
*/
// multipartFormDataContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
HttpResponseMessage response = await client.PostAsync(url, multipartFormDataContent);
if (!response.IsSuccessStatusCode)
{
Console.WriteLine("up image error");
Console.WriteLine(response.RequestMessage);
}
}
}
</code></pre>
</div>
<div id="MySignature" role="contentinfo">
痴者工良(https://whuanle.cn)<br><br>
来源：https://www.cnblogs.com/whuanle/p/11656734.html
頁:
[1]