Question

我正在使用ADAL令牌在Xamarin Forms项目中调用我的WebAPI。但是ADAL令牌在1小时后到期，http次来电将被授权。

我想在收到未经授权的状态时刷新令牌。我阅读了一些示例并说使用DelegatingHandler，但我不知道DelegatingHandler是什么以及如何将其与HTTP client一起使用。

Answer 1

根据您的描述，我检查了这个问题。要使用DelegatingHandler，您可以参考以下代码段：

<强> CustomMessageHandler：

public class CustomMessageHandler: DelegatingHandler
{
    private string _accessToken;
    private string _refreshToken;
    public CustomMessageHandler(string accessToken, string refreshToken)
    {
        _accessToken = accessToken;
        _refreshToken = refreshToken;
    }

    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", _accessToken);
        var response= await base.SendAsync(request, cancellationToken);
        if (response.StatusCode == HttpStatusCode.Unauthorized)
        {
            /* TODO:
             * 1. Retrieve the new access_token via the refresh_token
             * 2. Update the current field _accessToken
             * 3. Retry the previous failed request    
             */
        }
        return response;
    }
}

<强>用法：

 HttpClient client = new HttpClient(new CustomMessageHandler("{your-access-token}", "{your-refresh-token}"));

使用ADAL令牌正确处理HttpStatusCode = Unauthorized

1 个答案: