HttpContent边界双引号

Question

我有这个代码样本，它是作为另一个问题(Send a file via HTTP POST with C#)的答案发布的。它工作得很好，除了一个问题。它用双引号将HTTP标头中的边界括起来：

多部分/表单数据；boundary="04982073-787d-414b-a0d2-8e8a1137e145“

这会阻塞我正在尝试调用的the服务。浏览器没有那些双引号。我得找个办法告诉.NET别再玩了。

private System.IO.Stream Upload(string actionUrl, string paramString, Stream paramFileStream, byte [] paramFileBytes)
{
    HttpContent stringContent = new StringContent(paramString);
    HttpContent fileStreamContent = new StreamContent(paramFileStream);
    HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
    using (var client = new HttpClient())
    using (var formData = new MultipartFormDataContent())
    {
        formData.Add(stringContent, "param1", "param1");
        formData.Add(fileStreamContent, "file1", "file1");
        formData.Add(bytesContent, "file2", "file2");
        var response = client.PostAsync(actionUrl, formData).Result;
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }
        return response.Content.ReadAsStreamAsync().Result;
    }
}

Answer 1

您可以使用以下代码从边界中删除引号：

var boundary = formData.Headers.ContentType.Parameters.First(o => o.Name == "boundary"); 
boundary.Value = boundary.Value.Replace("\"", String.Empty);    

Answer 2

在similar issue in the dotnet runtime repo中展开讨论。选择不带引号包括两个步骤

1. 选择您自己的不带引号的boundary
2. remove自动生成的

标题，其中一个不带引号

private System.IO.Stream Upload(string actionUrl, string paramString, Stream paramFileStream, byte [] paramFileBytes)
{
    HttpContent stringContent = new StringContent(paramString);
    HttpContent fileStreamContent = new StreamContent(paramFileStream);
    HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
    //Set your own boundary, otherwise the internal boundary between multiple parts remains with quotes
    string boundaryDelimiter = String.Format("----------{0}", DateTime.Now.Ticks.ToString("x"));
    using (var client = new HttpClient())
    using (var formData = new MultipartFormDataContent(boundaryDelimiter))
    {
        formData.Add(stringContent, "param1", "param1");
        formData.Add(fileStreamContent, "file1", "file1");
        formData.Add(bytesContent, "file2", "file2");
        //remove quotes from ContentType Header
        _multiPartContent.Headers.Remove("Content-Type");
        _multiPartContent.Headers.TryAddWithoutValidation("Content-Type", "multipart/form-data; boundary=" + boundaryDelimiter);

        var response = client.PostAsync(actionUrl, formData).Result;
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }
        return response.Content.ReadAsStreamAsync().Result;
    }
}

Answer 3

这是一个老问题，但我也有同样的问题，用@Luis Perez在他的答案中指出的同样的方法解决了，但使用它有一个缺点，MultipartContent不再计算内容大小，所以这是我的解决方案：

var multipartContent = new MultipartFormDataContent();
var boundaryParameter = multipartContent.Headers.ContentType
                                        .Parameters.Single(p => p.Name == "boundary");
boundaryParameter.Value = boundaryParameter.Value.Replace("\"", "");

// --- Put the rest of content here

var size = (await multipartContent.ReadAsStreamAsync()).Length;
multipartContent.Headers.ContentLength = size;

希望这能对外面的人有所帮助。