HttpContent.ReadAsStringAsync导致请求挂起

Question

在ASP.NET WebAPi 2代码中，我有一个委托处理程序

public class RequestHandler1 : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var formData2 = await ReadContent(request);
        return await base.SendAsync(request, cancellationToken);
    }

    private static async Task<string> ReadContent(HttpRequestMessage request)
    {
        using (var ms = new MemoryStream())
        {
            await request.Content.CopyToAsync(ms);
            ms.Seek(0, SeekOrigin.Begin);

            using (var sr = new StreamReader(ms, Encoding.UTF8, true, 100, true))
            {
                return sr.ReadToEnd();
            }
        }
    }

    private static async Task<string> ReadContent3(HttpRequestMessage request)
    {
        var text = await request.Content.ReadAsStringAsync();
        return text;
    }
}

这个问题与HttpContent.ReadAsStringAsync causes request to hang (or other strange behaviours)有关，但在那个帖子中从来没有得到正确的回答。

当我调用return await base.SendAsync(request, cancellationToken);时，它就挂了。我是调用ReadContent还是ReadContent3都无关紧要

还有什么建议吗？

Answer 1

试试这段代码

public class CustomLogHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var logMetadata = await BuildRequestMetadata(request);
        var response = await base.SendAsync(request, cancellationToken);
        logMetadata = await BuildResponseMetadata(logMetadata, response);
        await SendToLog(logMetadata);
        return response;
    }
    private async Task<LogMetadata> BuildRequestMetadata(HttpRequestMessage request)
    {
        LogMetadata log = new LogMetadata
        {
            RequestMethod = request.Method.Method,
            RequestTimestamp = DateTime.Now,
            RequestUri = request.RequestUri.ToString(),
            RequestContent = await request.Content.ReadAsStringAsync(),
        };
        return log;
    }
    private async Task<LogMetadata> BuildResponseMetadata(LogMetadata logMetadata, HttpResponseMessage response)
    {
        logMetadata.ResponseStatusCode = response.StatusCode;
        logMetadata.ResponseTimestamp = DateTime.Now;
        logMetadata.ResponseContentType = response.Content == null ? string.Empty : response.Content.Headers.ContentType.MediaType;
        logMetadata.Response = await response.Content.ReadAsStringAsync();
        return logMetadata;
    }
    private async Task<bool> SendToLog(LogMetadata logMetadata)
    {
        try
        {
            //write your code
        }
        catch
        {
            return false;
        }
        return true;
    }

}