指向Windows 10 UWP时PostAsync抛出IRandomAccessStream错误

时间:2015-08-02 16:34:01

标签: c# windows-runtime uwp

我正在将Windows 8.1应用程序移植到Windows 10 UWP,但调用PostAsync现在会抛出异常。

这个确切的代码在定位8.1时效果很好,但是当我以Windows 10 UWP为目标时,它会引发以下异常:

This IRandomAccessStream does not support the GetInputStreamAt method because it requires cloning and this stream does not support cloning.

代码

    public async void TestPost()
    {
        var parameters = GetParameters();
        var formattedData = new FormUrlEncodedContent(parameters);
        using (var clientHandler = new HttpClientHandler { Credentials = GetCredentials() })
        {
            using (var httpClient = new HttpClient(clientHandler))
            {
                var response = await httpClient.PostAsync(postUrl, formattedData);
            }
        }
    }

private Dictionary<string, string> GetParameters()
{
    var parameters = new Dictionary<string, string>();
    parameters["grant_type"] = "url";
    parameters["device_id"] = "unique key";
    parameters["redirect_uri"] = "redirect url";
    return parameters;
}

public static NetworkCredential GetCredentials()
{
    return new NetworkCredential("<secret key>", "");
}

堆栈跟踪

 at System.IO.NetFxToWinRtStreamAdapter.ThrowCloningNotSuported(String methodName)
   at System.IO.NetFxToWinRtStreamAdapter.GetInputStreamAt(UInt64 position)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.Http.HttpHandlerToFilter.<SendAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.Http.HttpClientHandler.<SendAsync>d__1.MoveNext()

3 个答案:

答案 0 :(得分:2)

您是否尝试过使用Windows.Web.Http.HttpClient

// using Windows.Web.Http;
// using Windows.Web.Http.Filters;

var parameters = GetParameters();
var formattedData = new HttpFormUrlEncodedContent(parameters);
using (var clientHandler = new HttpBaseProtocolFilter())
{
    clientHandler.ServerCredential = GetCredentials();

    using (var httpClient = new HttpClient(clientHandler))
    {
        var response = await httpClient.PostAsync(postUrl, formattedData);
    }
}

答案 1 :(得分:0)

这是一个错误。解决方法是使用Windows.Web

using Windows.Web.Http;
using Windows.Web.Http.Filters;
using Windows.Web.Http.Headers;

    /// <summary>
    /// Performs the post asynchronous.
    /// </summary>
    /// <typeparam name="T">The generic type parameter.</typeparam>
    /// <param name="uri">The URI.</param>
    /// <param name="objectToPost">The object to post.</param>
    /// <returns>The response message.</returns>
    private static async Task<HttpResponseMessage> PerformPostAsync<T>string uri, object objectToPost)
    {
        HttpResponseMessage response = null;

        // Just add default filter (to enable enterprise authentication)
        HttpBaseProtocolFilter filter = new HttpBaseProtocolFilter();

        using (HttpClient client = HttpService.CreateHttpClient(filter))
        {
            // Now create the new request for the post
            HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, new Uri(uri));

            if (objectToPost != null)
            {
                // Frist get the bytes
                byte[] bytes = UTF8Encoding.UTF8.GetBytes(JsonHelper.Serialize(objectToPost));

                // Now create the HttpBufferContent from the bytes and set the request content
                IHttpContent content = new HttpBufferContent(bytes.AsBuffer());
                content.Headers.ContentType = HttpMediaTypeHeaderValue.Parse(HttpService.JsonMediaType);
                request.Content = content;
            }

            // Now complete the request
            response = await client.SendRequestAsync(request);
        }

        return response;
    }

    /// <summary>
    /// Creates the HTTP client.
    /// </summary>
    /// <param name="filter">The filter.</param>
    /// <returns>HTTP client.</returns>
    private static HttpClient CreateHttpClient(HttpBaseProtocolFilter filter = null)
    {
        HttpClient client = new HttpClient(filter);
        client.DefaultRequestHeaders.Accept.Add(new HttpMediaTypeWithQualityHeaderValue(HttpService.JsonMediaType));
        return client;
    }
}

答案 2 :(得分:0)

我们需要将PCL System.Net.Http库用于跨平台,因此我们无法将所有内容交换为使用特定于平台的库。我们最终为特定的问题案例使用了不同的HttpMessageHandler。该处理程序将实际调用委托给Windows.Web.Http库。

/// <summary>
/// A System.Net.Http message handler that delegates out to Windows.Web.Http.HttpClient.
/// </summary>
public class WindowsHttpMessageHandler : HttpMessageHandler
{
    private const string UserAgentHeaderName = "User-Agent";

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        Windows.Web.Http.HttpClient client = new Windows.Web.Http.HttpClient();

        Windows.Web.Http.HttpRequestMessage webRequest = new Windows.Web.Http.HttpRequestMessage
        {
            Method = ConvertMethod(request.Method),
            RequestUri = request.RequestUri,
            Content = await ConvertRequestContentAsync(request.Content).ConfigureAwait(false),
        };

        CopyHeaders(request.Headers, webRequest.Headers);

        Windows.Web.Http.HttpResponseMessage webResponse = await client.SendRequestAsync(webRequest)
            .AsTask(cancellationToken)
            .ConfigureAwait(false);

        HttpResponseMessage response = new HttpResponseMessage
        {
            StatusCode = ConvertStatusCode(webResponse.StatusCode),
            ReasonPhrase = webResponse.ReasonPhrase,
            Content = await ConvertResponseContentAsync(webResponse.Content).ConfigureAwait(false),
            RequestMessage = request,
        };

        CopyHeaders(webResponse.Headers, response.Headers);

        return response;
    }

    private static void CopyHeaders(HttpRequestHeaders input, Windows.Web.Http.Headers.HttpRequestHeaderCollection output)
    {
        foreach (var header in input)
        {
            output.Add(header.Key, GetHeaderValue(header.Key, header.Value));
        }
    }

    private static void CopyHeaders(HttpContentHeaders input, Windows.Web.Http.Headers.HttpContentHeaderCollection output)
    {
        foreach (var header in input)
        {
            output.Add(header.Key, GetHeaderValue(header.Key, header.Value));
        }
    }

    private static void CopyHeaders(Windows.Web.Http.Headers.HttpContentHeaderCollection input, HttpContentHeaders output)
    {
        foreach (var header in input)
        {
            if (!string.Equals(header.Key, "Expires", StringComparison.OrdinalIgnoreCase) || header.Value != "-1")
            {
                output.Add(header.Key, header.Value);
            }
        }
    }

    private static void CopyHeaders(Windows.Web.Http.Headers.HttpResponseHeaderCollection input, HttpResponseHeaders output)
    {
        foreach (var header in input)
        {
            output.Add(header.Key, header.Value);
        }
    }

    private static string GetHeaderValue(string name, IEnumerable<string> value)
    {
        return string.Join(string.Equals(name, UserAgentHeaderName, StringComparison.OrdinalIgnoreCase) ? " " : ",", value);
    }

    private static Windows.Web.Http.HttpMethod ConvertMethod(HttpMethod method)
    {
        return new Windows.Web.Http.HttpMethod(method.ToString());
    }

    private static async Task<Windows.Web.Http.IHttpContent> ConvertRequestContentAsync(HttpContent content)
    {
        if (content == null)
        {
            return null;
        }

        Stream contentStream = await content.ReadAsStreamAsync().ConfigureAwait(false);
        var result = new Windows.Web.Http.HttpStreamContent(contentStream.AsInputStream());

        CopyHeaders(content.Headers, result.Headers);

        return result;
    }

    private static async Task<HttpContent> ConvertResponseContentAsync(Windows.Web.Http.IHttpContent content)
    {
        var responseStream = await content.ReadAsInputStreamAsync();
        var result = new StreamContent(responseStream.AsStreamForRead());

        CopyHeaders(content.Headers, result.Headers);

        return result;
    }

    private static HttpStatusCode ConvertStatusCode(Windows.Web.Http.HttpStatusCode statusCode)
    {
        return (HttpStatusCode)(int)statusCode;
    }
}

虽然我们只需要拨打几个电话,但并未对所有用例进行100%测试。