您如何将基本身份验证与 System.Net.Http.HttpClient 一起使用？

Question

我正在尝试在 c# .net core 中实现一个 rest 客户端，它需要首先进行基本身份验证，然后在后续请求中利用一个 Bearer 令牌。

当我尝试将基本身份验证与带有 FormUrlEncodedContent 对象的 client.PostAsync 结合使用时，出现异常：

System.InvalidOperationException occurred in System.Net.Http.dll: 'Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects.'

//setup reusable http client
HttpClient client = new HttpClient();
Uri baseUri = new Uri(url);
client.BaseAddress = baseUri;
client.DefaultRequestHeaders.Clear();
client.DefaultRequestHeaders.ConnectionClose = true;

//Post body content
var values = new List<KeyValuePair<string,string>>();
values.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));

var content = new FormUrlEncodedContent(values);

//Basic Authentication
var authenticationString = $"{clientId}:{clientSecret}";
var base64EncodedAuthenticationString = Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes(authenticationString));
content.Headers.Add("Authorization", $"Basic {base64EncodedAuthenticationString}");

//make the request
var task = client.PostAsync("/oauth2/token",content);
var response = task.Result;
response.EnsureSuccessStatusCode();
string responseBody = response.Content.ReadAsStringAsync().Result;
Console.WriteLine(responseBody);

Exception has occurred: CLR/System.InvalidOperationException
An unhandled exception of type 'System.InvalidOperationException' occurred in System.Net.Http.dll: 'Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects.'
   at System.Net.Http.Headers.HttpHeaders.GetHeaderDescriptor(String name)
   at System.Net.Http.Headers.HttpHeaders.Add(String name, String value)

Answer 1

从调用代码显式创建 HttpClient 并不是一个好习惯。请使用HttpClientFactory来简化很多事情。

但是，如果您想使用基本身份验证，只需创建HttpRequestMessage并添加以下标头：

var request = new HttpRequestMessage(HttpMethod.Post, getPath)
{
    Content = new FormUrlEncodedContent(values)
};
request.Headers.Authorization = new BasicAuthenticationHeaderValue("username", "password");
// other settings

如果您决定使用推荐的 IHttpClientFactory，那就更简单了：

serviceCollection.AddHttpClient(c =>
{
   c.BaseAddress = new Uri("your base url");
   c.SetBasicAuthentication("username", "password");
})

Answer 2

看起来您不能使用 PostAsync 并且可以访问用于身份验证的标题。我不得不使用 HttpRequestMessage 和 SendAsync。

//setup reusable http client
HttpClient client = new HttpClient();
Uri baseUri = new Uri(url);
client.BaseAddress = baseUri;
client.DefaultRequestHeaders.Clear();
client.DefaultRequestHeaders.ConnectionClose = true;

//Post body content
var values = new List<KeyValuePair<string, string>>();
values.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));
var content = new FormUrlEncodedContent(values);

var authenticationString = $"{clientId}:{clientSecret}";
var base64EncodedAuthenticationString = Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes(authenticationString));

var requestMessage = new HttpRequestMessage(HttpMethod.Post, "/oauth2/token");
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Basic", base64EncodedAuthenticationString);
requestMessage.Content = content;

//make the request
var task = client.SendAsync(requestMessage);
var response = task.Result;
response.EnsureSuccessStatusCode();
string responseBody = response.Content.ReadAsStringAsync().Result;
Console.WriteLine(responseBody);

Answer 3

不要编码整个身份验证字符串 - 编码“用户名：密码”表达式并将结果附加到“基本”前缀。

var authenticationString = $"{clientId}:{clientSecret}";
var base64EncodedAuthenticationString = Convert.ToBase64String(System.Text.ASCIIEncoding.UTF8.GetBytes(authenticationString));
content.Headers.Add("Authorization", "Basic " + base64EncodedAuthenticationString);

此外，请考虑仅使用 ASCII 编码 - 服务器可能无法理解 UTF8，除非您charset向标头添加声明。

维基百科似乎很好地涵盖了这一点。

Answer 4

具体问题是这一行（如下）

content.Headers.Add("Authorization", $"Basic {base64EncodedAuthenticationString}");

这会失败，因为HttpContent.Headers( System.Net.Http.Headers.HttpContentHeaders) 仅适用于特定于内容的标头，例如Content-Type、Content-Length等。

你已经声明你不能使用它DefaultRequestHeaders，因为你只需要它用于一个请求 - 但你也不能使用它PostAsync- 只有SendAsync你自己构建HttpRequestMessage，根据你自己的答案 和@NeilMoss的答案- 但你将来可以使用扩展方法。

但为了其他读者的利益，另一种选择是在现有的基础上添加一个新的扩展方法PostAsync，这实际上非常简单（只有 3 行！）：

public Task<HttpResponseMessage> PostAsync( this HttpClient httpClient, Uri requestUri, HttpContent content, String basicUserName, String basicPassword, String? challengeCharSet = null, CancellationToken cancellationToken = default )
{
    if( basicUserName.IndexOf(':') > -1 ) throw new ArgumentException( message: "RFC 7617 states that usernames cannot contain colons.", paramName: nameof(basicUserName) );

    HttpRequestMessage httpRequestMessage = new HttpRequestMessage( HttpMethod.Post, requestUri );
    httpRequestMessage.Content = content;

    //

    Encoding encoding = Encoding.ASCII;
    if( challengeCharSet != null )
    {
        try
        {
            encoding = Encoding.GetEncoding( challengeCharSet );
        }
        catch
        {
            encoding = Encoding.ASCII;
        }
    }

    httpRequestMessage.Headers.Authorization = new AuthenticationHeaderValue(
        scheme   : "Basic",
        parameter: Convert.ToBase64String( encoding.GetBytes( userName + ":" + password ) )
    );

    return SendAsync( httpRequestMessage, cancellationToken );
}

用法：

HttpClient httpClient = ...

using( HttpResponseMessage response = await httpClient.PostAsync( uri, content, basicUserName: "AzureDiamond", basicPassword: "hunter2" ).ConfigureAwait(false) )
{
    // ...
}

Answer 5

使用 .NET 6，我使用该HttpClient.DefaultRequestHeaders.Authorization属性来设置授权标头。

// This example will send a signing request to the RightSignature API
var api = "https://api.rightsignature.com/public/v2/sending_requests";

// requestJson is the serialized JSON request body
var contentData = new StringContent(requestJson, Encoding.UTF8, "application/json");

// Instantiate client (for testing), use Microsoft's guidelines in production
var client = new HttpClient();

// Use basic auth, the token has already been converted to base64
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", tokenB64);

try
{
    var response = await client.PostAsync(api, contentData);
}
...

祝你好运！