14

我正在尝试从新的 Asp.Net Web Api 中的请求中提取一些数据。我有一个这样的处理程序设置：

public class MyTestHandler : DelegatingHandler
{
    protected override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
        if (request.Content.IsFormData())
        {
            request.Content.ReadAsStreamAsync().ContinueWith(x => {
                var result = "";
                using (var sr = new StreamReader(x.Result))
                {
                    result = sr.ReadToEnd();
                }
                Console.Write(result);
            });
        }

        return base.SendAsync(request, cancellationToken);
    }
}

这是我的http请求：

POST http://127.0.0.1/test HTTP/1.1
Connection: Keep-Alive
Content-Length: 29
Content-Type: application/x-www-form-urlencoded
Expect: 100-continue
Host: 127.0.0.1

my_property=my_value

问题是，无论我如何尝试从中读取信息，request.Content它总是空的。我试过了

request.Content.ReadAsStreamAsync
request.Content.ReadAsFormDataAsync
request.Content.ReadAs<FormDataCollection>

也

    [HttpGet,HttpPost]
    public string Index([FromBody]string my_property)
    {
        //my_property == null
        return "Test";
    }

如果有效，则没有。我无法从体内取出数据。我在 Windows 7 上的 IIS 内托管并使用 Fiddler 提交请求。我究竟做错了什么？

4

6 回答 6

20

问题是使用 Web Api 只能读取一次正文。我运行了一个 HTTP 模块，它记录了请求的所有详细信息并正在读取正文。

于 2012-08-17T16:32:11.083 回答
7

这很丑陋，但是从最初的修补看来，实际上您可以替换 DelegatingHandler 中的 Content ...

protected override Task SendAsync(
          HttpRequestMessage request,
          CancellationToken cancellationToken)
      {                    
          Stream stream = new MemoryStream();

          request.Content.ReadAsStreamAsync().Result.CopyTo(stream);
          stream.Seek(0,SeekOrigin.Begin);

          // copy off the content "for later"
          string query = new StreamReader(stream).ReadToEnd();
          stream.Seek(0,SeekOrigin.Begin);

          // if further processing depends on content type
          // go ahead and grab current value
          var contentType = request.Content.Headers.ContentType;

          request.Content = new StreamContent(stream);
          request.Content.Headers.ContentType = contentType;

          return base.SendAsync(request, cancellationToken);
     }

我不知道这是好还是坏（怀疑不好），但是....它似乎工作并遵循我见过的模型，推荐给那些需要修改请求标头和内容的人“在路上”一个委托处理程序。

您的里程可能会有很大差异。

于 2012-10-06T13:10:18.987 回答
6

我的答案基于 brmore 的代码；

此函数可以安全地读取任何处理程序中的内容

private string SafeReadContentFrom(HttpRequestMessage request)
{
     var contentType = request.Content.Headers.ContentType;
     var contentInString = request.Content.ReadAsStringAsync().Result;
     request.Content = new StringContent(contentInString);
     request.Content.Headers.ContentType = contentType;
     return contentInString;
}
于 2013-11-28T09:36:16.117 回答
2

这对我有用。

[HttpPost]
public IHttpActionResult Index(HttpRequestMessage request)
{
    var form = request.Content.ReadAsFormDataAsync().Result;
    return Ok();
}
于 2016-05-12T08:20:47.593 回答
0

我遇到了同样的问题，最后选择不在日志中写入内容。我生活在记录内容类型和内容长度。

但尽可能将所有内容写入日志中始终是一个好主意。

但似乎目前使用 WebApi 我们无法实现这一点。

于 2012-08-27T04:41:51.000 回答
0

您可以先创建提供程序。MultipartMemoryStreamProvider() 然后Request.Content.ReadAsMultipartAsync(provider); 然后阅读内容

public async Task<IHttpActionResult> Post(int id, string type)
{
    // Check if the request contains multipart/form-data.
    if(!Request.Content.IsMimeMultipartContent("form-data"))
        return BadRequest("Unsupported media type");

    try
    {
        var azureManager = new AzureManager();
        var imageManager = new ImageManager();
        var provider = new MultipartMemoryStreamProvider();

        await Request.Content.ReadAsMultipartAsync(provider);

        var assets = new List<Asset>();
        foreach (var file in provider.Contents)
        {
            var stream = await file.ReadAsStreamAsync();
            var guid = Guid.NewGuid();
            string blobName = guid.ToString();

            await azureManager.UploadAsync(blobName, stream);

            var asset = new Asset
            {
                PropertyId = id,
                FileId = guid,
                FileName = file.Headers.ContentDisposition.FileName.Trim('\"').ToLower(),
                FileSize = file.Headers.ContentLength ?? 0,
                MimeType = file.Headers.ContentType.MediaType.ToLower()
            };

            if (type == "photos")
            {
                asset.Type = AssetType.Photo;

                // Resize and crop copies to 16:9
                using (MemoryStream thumb = imageManager.ResizeImage(stream, 320, 180))
                {
                    await azureManager.UploadAsync(blobName, thumb, BlobContainers.Thumbs);
                }
                using (MemoryStream photo = imageManager.ResizeImage(stream, 1024, 576))
                {
                    await azureManager.UploadAsync(blobName, photo, BlobContainers.Photos);
                }
            }
            else
                asset.AssumeType();

            assets.Add(asset);
        }

        db.Assets.AddRange(assets);
        await db.SaveChangesAsync();

        return Ok(new { Message = "Assets uploaded ok", Assets = assets });
    }
    catch (Exception ex)
    {
        return BadRequest(ex.GetBaseException().Message);
    }
}
于 2015-02-05T15:56:35.810 回答