C# HttpClient设置DefaultRequestHeaders Authorization未随请求发送问题

原HttpClient实现代码 #

private HttpClient GetHttpClient()
{
    HttpClient client = new HttpClient()
        {
            BaseAddress = new Uri(Settings.BaseAddress)
        };

    client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Settings.ApiKey);

    // 尝试过直接添加头的方式也无效
    // client.DefaultRequestHeaders.Add( "Authorization", "Basic " + Settings.ApiKey);

    return client;
}

private async Task<string> GetAccount()
{
    using (HttpClient httpClient = GetHttpClient())
    {
        HttpResponseMessage response = await httpClient.GetAsync($"/v1/accounts/{Settings.AccountNumber}");
        response.EnsureSuccessStatusCode();
        string json = await response.Content.ReadAsStringAsync();
    }

    return await Task.FromResult((string)null);
}

已在HttpClient实例上配置了默认的Authorization请求头，但实际发送请求时该头并未被包含在内（注：抓包结果显示请求中无此头）。

更新：改用WebRequest方式仍无效 #

string authorization = Convert.ToBase64String(Encoding.ASCII.GetBytes($"{Settings.ApiKey}"));
// 生成的Base64值为 c2tfbGl2ZV9YREpEUnR2eFVhRmpyMmoydkZJTm9kemE6

// 但Firefox中捕获到的有效授权值是
// c2tfbGl2ZV9YREpEUnR2eFVhRmpyMmoydkZJTm9kemE6dW5kZWZpbmVk

authorization = "c2tfbGl2ZV9YREpEUnR2eFVhRmpyMmoydkZJTm9kemE6dW5kZWZpbmVk";

var request = WebRequest.Create($"{Settings.BaseAddress}/v1/accounts/{Settings.AccountNumber}");
// 尝试过用AuthenticationHeaderValue的方式也无效
// AuthenticationHeaderValue h = new AuthenticationHeaderValue("Basic", authorization);
request.Headers.Add("authorization", "Basic " + authorization);

string text;
var rr = (HttpWebResponse)request.GetResponse();

using (var sr = new StreamReader(rr.GetResponseStream()))
{
    text = sr.ReadToEnd();
}

对比验证：wget命令可正常请求 #

# wget --header="Authorization: Basic c2tfbGl2ZV9YREpEUnR2eFVhRmpyMmoydkZJTm9kemE6" https://api.example.com/v1/accounts/accountNumber --output-document -

以上命令能够成功获取到接口返回内容。

内容的提问来源于stack exchange，提问作者Richard Barraclough