我一直在使用HttpClient构建REST客户端，但我无法弄清楚如何向服务器进行身份验证，也找不到任何示例。最有可能我会使用基本身份验证，但确实任何示例都会受到赞赏。
在早期版本中（有在线示例），您可以这样做：
HttpClient client = new HttpClient("http://localhost:8080/ProductService/");
client.TransportSettings.Credentials =
new System.Net.NetworkCredential("admin", "admin");
然而，在版本0.3.0中，TransportSettings属性已不再存在。
所有这些都已经过时了。最终的方法如下：
var credentials = new NetworkCredential(userName, password);
var handler = new HttpClientHandler { Credentials = credentials };
using (var http = new HttpClient(handler))
{
// ...
}
HttpClient库没有被纳入.NET 4中。但是可以在这里找到它：http://nuget.org/List/Packages/HttpClient。不过，在这个版本的HttpClient中，身份验证是以不同的方式完成的。
var httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Authorization
= new AuthenticationHeaderValue("basic","...");
var webRequestHandler = new WebRequestHandler();
CredentialCache creds = new CredentialCache();
creds.Add(new Uri(serverAddress), "basic",
new NetworkCredential("user", "password"));
webRequestHandler.Credentials = creds;
var httpClient = new HttpClient(webRequestHandler);
请注意，这个库将在下周更新，并且会有一些小的破坏性改变！
using (var client = new HttpClient())
{
var encoding = new ASCIIEncoding();
var authHeader = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(encoding.GetBytes(string.Format("{0}:{1}", "username", "password"))));
client.DefaultRequestHeaders.Authorization = authHeader;
// Now, the Authorization header will be sent along with every request, containing the username and password.
}
从.NET 4.8开始，.NET Core 3.1和.NET Standard 2.0建议同时使用HttpClient和CredentialCache。类似于这样：
const string basicAuthUser = @"myUser";
const string basicAuthPass = @"myPass";
const string host = @"https://my.host.com";
const string path = @"/api";
using (var httpClientHandler = new HttpClientHandler()) {
httpClientHandler.PreAuthenticate = true;
httpClientHandler.UseDefaultCredentials = true;
var basicCredCache = new CredentialCache();
var basicCredentials = new NetworkCredential(basicAuthUser, basicAuthPass);
basicCredCache.Add(new Uri(new Uri(host), path), "Basic", basicCredentials);
httpClientHandler.Credentials = basicCredCache;
using (var client = new HttpClient(httpClientHandler)) {
client.BaseAddress = new Uri(host);
using (var request = new HttpRequestMessage(HttpMethod.Get /*HttpMethod.Post*/, path)) {
//
// Send request here
//
}
}
}
注意：将HttpClient包装在using中可能会在高负载下导致Socket耗尽。 但是，保持HttpClient为单例可能会导致其他问题，例如旧的DNS问题。请从这里开始阅读这个长故事。
using( var client = new HttpClient() )
{
var byteArray = Encoding.ASCII.GetBytes("MyUSER:MyPASS");
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
....
}
正如此处的答案所概述的那样：
我相信这篇文章有些旧了，但是对于任何想要更新答案的人来说，当我建立我的测试服务器时，我使用了以下代码：
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("http://myServer/api/Person");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var byteArray = Encoding.ASCII.GetBytes($"{UserName}:{ApiPassword}");
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
或者这样也可以：
using (var http = new HttpClient())
{
// byteArray is username:password for the server
var byteArray = Encoding.ASCII.GetBytes("myUserName:myPassword");
http.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
string uri = "http://myServer/api/people" ;
var response = await http.GetStringAsync(uri);
List<Person> agencies = JsonConvert.DeserializeObject<List<Person>>(response);
foreach (Person person in people)
{
listBox1.Items.Add(person.Name);
}
}
我刚刚下载了0.3.0版本，它已经被移除了。现在在HttpClientChannel中。
HttpClient client = new HttpClient(...);
var channel = new HttpClientChannel();
channel.Credentials = new NetworkCredential(...);
client.Channel = channel;
如果没有明确指定，它将使用默认实例的HttpClientChannel。
更新：这在 .Net 4.5 中已经无效了；请参见下面的正确答案：https://dev59.com/yGs05IYBdhLWcg3wNPE3#15034995
只有在指定了DefaultRequestHeaders时才能正常工作，其他方式都不行。
HttpClientHandler.PreAuthenticate设为true，详情请参阅 http://msdn.microsoft.com/en-us/library/system.net.http.httpclienthandler.preauthenticate.aspx。 - Duncan Smart