Question

我正在尝试使用C＃中的HttpClient进行多部分表单发布，并且发现以下代码不起作用。

重要：

var jsonToSend = JsonConvert.SerializeObject(json, Formatting.None, new IsoDateTimeConverter());
var multipart = new MultipartFormDataContent();
var body = new StringContent(jsonToSend, Encoding.UTF8, "application/json");

multipart.Add(body);
multipart.Add(new ByteArrayContent(File.ReadAllBytes("test.txt")), "test", "test.txt");

var httpClient = new HttpClient();
var response = httpClient.PostAsync(new Uri("http://localhost:55530"), multipart).Result;

完整计划：

namespace CourierMvc.Worker
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                Console.WriteLine("Hit any key to make request.");
                Console.ReadKey();

                try
                {
                    var request = new RestRequest(Method.POST)
                    {
                        Resource = "http://localhost:55530"
                    };

                    var json = new CourierMessage
                    {
                        Id = Guid.NewGuid().ToString(),
                        Key = "awesome",
                        From = "khalid@home.com",
                        To = new[] { "me@test.com", "you@test.com" },
                        Subject = "test",
                        Body = "body",
                        Processed = DateTimeOffset.UtcNow,
                        Received = DateTime.Now,
                        Created = DateTime.Now,
                        Sent = DateTime.Now,
                        Links = new[] { new Anchor { Link = "http://google.com" }, new Anchor { Link = "http://yahoo.com" } }
                    };

                    var jsonToSend = JsonConvert.SerializeObject(json, Formatting.None, new IsoDateTimeConverter());
                    var multipart = new MultipartFormDataContent();
                    var body = new StringContent(jsonToSend, Encoding.UTF8, "application/json");

                    multipart.Add(body);
                    multipart.Add(new ByteArrayContent(File.ReadAllBytes("test.txt")), "test", "test.txt");

                    var httpClient = new HttpClient();
                    var response = httpClient.PostAsync(new Uri("http://localhost:55530"), multipart).Result;

                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
            }
        }
    }
}

我真的不知道为什么它不起作用。我把文件发布到端点，但是身体（json）永远不会到达那里。我做错了吗？

服务器端代码请求：

namespace CourierMvc.Controllers
{
    public class HomeController : Controller
    {
        //
        // GET: /Home/

        public ActionResult Index()
        {
            return Content("Home#Index");
        }


        [ValidateInput(false)]
        public ActionResult Create(CourierMessage input)
        {
            var files = Request.Files;

            return Content("OK");
        }

    }
}

路线配置：

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Create", id = UrlParameter.Optional }
    );

}

Answer 1

public class CourierMessage
{
    public string Id { get; set; }
    public string Key { get; set; }
    public string From { get; set; }
    public string Subject { get; set; }
    public string Body { get; set; }
    public DateTimeOffset Processed { get; set; }
    public DateTime Received { get; set; }
    public DateTime Created { get; set; }
    public DateTime Sent { get; set; }
    public HttpPostedFileBase File { get; set; }
}  




while (true)
{
    Console.WriteLine("Hit any key to make request.");
    Console.ReadKey();

    using (var client = new HttpClient())
    {
        using (var multipartFormDataContent = new MultipartFormDataContent())
        {
            var values = new[]
            {
                new KeyValuePair<string, string>("Id", Guid.NewGuid().ToString()),
                new KeyValuePair<string, string>("Key", "awesome"),
                new KeyValuePair<string, string>("From", "khalid@home.com")
                 //other values
            };

            foreach (var keyValuePair in values)
            {
                multipartFormDataContent.Add(new StringContent(keyValuePair.Value), 
                    String.Format("\"{0}\"", keyValuePair.Key));
            }

            multipartFormDataContent.Add(new ByteArrayContent(File.ReadAllBytes("test.txt")), 
                '"' + "File" + '"', 
                '"' + "test.txt" + '"');

            var requestUri = "http://localhost:5949";
            var result = client.PostAsync(requestUri, multipartFormDataContent).Result;
        }
    }
}

enter image description here

Answer 2

所以我看到的问题是MultipartFormDataContent请求消息将始终将请求的内容类型设置为“multipart / form-data”。将json结束并将其置于请求中仅“看起来”类似于模型绑定器作为字符串。

您的选择是：

让您的mvc操作方法接收一个字符串并反序列化到您的对象
将模型的每个属性作为表单部分发布
创建一个可处理您请求的自定义模型活页夹。
将操作分解为两个帖子，首先发送json元数据，另一个发送文件。来自服务器的响应应该发送一些id或密钥来关联这两个请求。

如果您将MultipartFormDataContent替换为MultipartContent，则可以通过the RFC document和the MSDN documentation阅读这些内容。但我还没有测试过。

Answer 3

这是如何使用MultipartFormDataContent使用HTTPClient发布字符串和文件流的示例。需要为每个HTTPContent指定Content-Disposition和Content-Type：

这是我的榜样。希望它有所帮助：


private static void Upload()
        {

            using (var client = new HttpClient())
            {
                client.DefaultRequestHeaders.Add("User-Agent", "CBS Brightcove API Service");

                using (var content = new MultipartFormDataContent())
                {
                    var path = @"C:\B2BAssetRoot\files\596086\596086.1.mp4";

                    string assetName = Path.GetFileName(path);

                    var request = new HTTPBrightCoveRequest()
                        {
                            Method = "create_video",
                            Parameters = new Params()
                                {
                                    CreateMultipleRenditions = "true",
                                    EncodeTo = EncodeTo.Mp4.ToString().ToUpper(),
                                    Token = "x8sLalfXacgn-4CzhTBm7uaCxVAPjvKqTf1oXpwLVYYoCkejZUsYtg..",
                                    Video = new Video()
                                        {
                                            Name = assetName,
                                            ReferenceId = Guid.NewGuid().ToString(),
                                            ShortDescription = assetName
                                        }
                                }
                        };

                    //Content-Disposition: form-data; name="json"
                    var stringContent = new StringContent(JsonConvert.SerializeObject(request));
                    stringContent.Headers.Add("Content-Disposition", "form-data; name=\"json\"");
                    content.Add(stringContent, "json");


                    FileStream fs = File.OpenRead(path);

                    var streamContent = new StreamContent(fs);
                    streamContent.Headers.Add("Content-Type", "application/octet-stream");
                    streamContent.Headers.Add("Content-Disposition", "form-data; name=\"file\"; filename=\"" + Path.GetFileName(path) + "\"");
                    content.Add(streamContent, "file", Path.GetFileName(path));

                    //content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");



                    Task message = client.PostAsync("http://api.brightcove.com/services/post", content);

                    var input = message.Result.Content.ReadAsStringAsync();
                    Console.WriteLine(input.Result);
                    Console.Read();
                }
            }
        }

Answer 4

string path = @"C:\New folder\Test.pdf";  // **ANY FILE**
                            
var formContent = new MultipartFormDataContent
{
     { new ByteArrayContent(File.ReadAllBytes(path)), "file", Path.GetFileName(path) }
};

var client = new HttpClient();
var response = client.PostAsync(_configuration["Url"], formContent).Result;

C＃中的HttpClient Multipart Form Post

4 个答案: