Question

我正在编写一个Web API服务，我想接受一个文件（图像）和一个包含图像关键信息的序列化对象（JSON）。没有图像部分的问题但是当我添加包含反序列化对象的字符串内容时，我在尝试确定哪个是哪个并且相应地采取行动时遇到问题。

客户端代码如下：

HttpClient client = new HttpClient();

MultipartFormDataContent content = new MultipartFormDataContent();
content.Add(new StreamContent(File.Open("c:\\MyImages\\Image00.jpg", FileMode.Open)), "image_file", "Image00.jpg");

ImageKeys ik = new ImageKeys { ImageId = "12345", Timestamp = DateTime.Now.ToString() };
JavaScriptSerializer js = new JavaScriptSerializer();
if (ik != null)
{
    content.Add(new StringContent(js.Serialize(ik), Encoding.UTF8, "application/json"), "image_keys");
}

string uri = "http://localhost/MyAPI/api/MyQuery/TransferFile";
var request = new HttpRequestMessage()
{
    RequestUri = new Uri(uri),
    Method = HttpMethod.Post
};

request.Content = content;

string responseStr = "";
try
{
    HttpResponseMessage result = client.SendAsync(request).Result;
    string resultContent = string.Format("{0}:{1}", result.StatusCode, result.ReasonPhrase);

    //
    // Handle the response
    //
    responseStr = resultContent;
}
catch (Exception ex)
{
    responseStr = ex.Message;
}

listBox1.Items.Add(responseStr);

所以我首先包含图像文件，然后是序列化对象StringContent。在服务器端，我使用以下代码来解析消息。

HttpRequestMessage request = this.Request;
HttpResponseMessage ret = new HttpResponseMessage();

//
// Verify that this is an HTML Form file upload request
//
if (!request.Content.IsMimeMultipartContent())
{
    throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}

string root = "c:\\tmp\\uploads";
if (!Directory.Exists(root))
{
    Directory.CreateDirectory(root);
}

//
// Create a stream provider for setting up output streams that saves the output under c:\tmp\uploads
// If you want full control over how the stream is saved then derive from MultipartFormDataStreamProvider
// and override what you need.
//
MultipartFormDataStreamProvider streamProvider = new MultipartFormDataStreamProvider(root);

try
{
    await request.Content.ReadAsMultipartAsync(streamProvider);
    foreach (var file in streamProvider.Contents)
    {
        if (file.Headers.ContentDisposition.Name == "image_file")
        {
            FileInfo finfo = new FileInfo(streamProvider.FileData.First().LocalFileName);

            string destFile = Path.Combine(root, streamProvider.FileData.First().Headers.ContentDisposition.FileName.Replace("\"", ""));
            //
            // File.Move cannot deal with duplicate files
            // Ensure that the target does not exist. 
            //
            if (File.Exists(destFile))
            {
                File.Delete(destFile);
            }

            File.Move(finfo.FullName, destFile);
        }
        else if (file.Headers.ContentDisposition.Name == "image_keys")
        {
            // deserialize key class
            string str = file.ReadAsStringAsync().Result;

            JavaScriptSerializer js = new JavaScriptSerializer();
            ImageKeys ik = js.Deserialize<ImageKeys>(str);
        }
    }

    ret.StatusCode = HttpStatusCode.OK;
    ret.Content = new StringContent("File uploaded.");
}
catch (Exception ex)
{
    ret.StatusCode = HttpStatusCode.UnsupportedMediaType;
    ret.Content = new StringContent("File upload failed.");
}

return ret;

foreach循环尝试将多部分内容中的每个项目作为文件处理，但我想分别处理各种内容类型，但我不清楚它们是如何描绘的。感谢

Answer 1

您可以将 Content 转换为 MultipartFormDataContent 并对其进行迭代。根据内容类型，您可以将其作为文件或字符串读取。字符串内容类型示例：

var dataContents = request.Content as MultipartFormDataContent;

foreach (var dataContent in dataContents)
{
    var name = dataContent.Headers.ContentDisposition.Name;
    var value = dataContent.ReadAsStringAsync().Result;
    ...
}

如何解析MultipartFormDataContent

1 个答案: