无法使用 HttpClient 获取 API 资源答案

【问题标题】：Can't get API resource using HttpClient无法使用 HttpClient 获取 API 资源
【发布时间】：2018-06-17 17:18:54
【问题描述】：

我正在使用 Identity Server4，并且我已经使用 ResourceOwnerPassword 授权类型配置了一个 Web API 项目。

Web API 方法：

[HttpGet]
[Authorize(Roles = "Badmin")]
[Route("GetUsers")]
public IActionResult GetUsers()
{
    List<ApplicationUser> users = _context.ApplicationUsers
        .AsNoTracking().ToListAsync().Result;

    return Json(users);
}

在我的控制台程序代码中：

if (response != null)
{
    using (HttpClient client = new HttpClient())
    {
        Console.WriteLine("AccessToken:" + Environment.NewLine + response.AccessToken);
        Console.WriteLine(Environment.NewLine);

        HttpResponseMessage resourceOwnerPasswordResponse = await client.GetAsync("https://localhost:44366/identity/GetUsers");

        client.DefaultRequestHeaders.Add("Bearer", response.AccessToken);

        if (!resourceOwnerPasswordResponse.IsSuccessStatusCode)
        {
            Console.WriteLine(resourceOwnerPasswordResponse.StatusCode);
            Console.WriteLine("HttpClient ResourceOwnerPassword Result: " + resourceOwnerPasswordResponse.StatusCode);
            Console.WriteLine(Environment.NewLine);
        }
        else
        {
            string result = await resourceOwnerPasswordResponse.Content.ReadAsStringAsync();
            Console.WriteLine("HttpClient ResourceOwnerPassword Result: " + Environment.NewLine + JsonConvert.DeserializeObject(result));
            Console.WriteLine(Environment.NewLine);
        }
    }
}

第二种方式：

if (response != null)
{
    HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create("https://localhost:44366/identity/GetUsers");
    httpWebRequest.ContentType = "application/json";
    httpWebRequest.Headers.Add("Authorization", string.Format("Bearer {0}", response.AccessToken));
    httpWebRequest.Method = "GET";

    HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();

    string result = string.Empty;

    using (Stream responseStream = httpWebResponse.GetResponseStream())
    {
        if (responseStream != null)
        {
            StreamReader streamReader = new StreamReader(responseStream);
            result = streamReader.ReadToEnd();
            streamReader.Close();
        }
    }

    Console.WriteLine("HttpWebRequest ResourceOwnerPassword Result: " + Environment.NewLine + JsonConvert.DeserializeObject(result));
}

查看控制台结果：

所以我的问题是为什么当我使用HttpCliet 时，我得到未经授权（代码 401），而第二种方式成功获取了用户数据。

【问题讨论】：

标签： c# asp.net-core identityserver4 dotnet-httpclient asp.net-core-webapi

【解决方案1】：

令牌应该在发出请求之前添加到客户端，并且您需要确保它是授权标头。

client.DefaultRequestHeaders.Authorization = 
    new AuthenticationHeaderValue("Bearer", response.AccessToken);

//OR

//client.DefaultRequestHeaders
//  .Add("Authorization", string.Format("Bearer {0}", response.AccessToken));

var resourceOwnerPasswordResponse = await client.GetAsync("https://localhost:44366/identity/GetUsers");

这就是为什么它在第二个示例而不是第一个示例中起作用

如果使用ToListAsync，Web API 操作也应该是异步的

[HttpGet]
[Authorize(Roles = "Badmin")]
[Route("GetUsers")]
public async Task<IActionResult> GetUsers() {
    var users = await _context.ApplicationUsers.AsNoTracking().ToListAsync();

    return Json(users);
}

【讨论】：