HttpClient：如何一次上传多个文件

Question

我正在尝试使用System.Net.Http.HttpClient 上传多个文件。

using (var content = new MultipartFormDataContent())
{
   content.Add(new StreamContent(imageStream), "image", "image.jpg");
   content.Add(new StreamContent(signatureStream), "signature", "image.jpg.sig");

   var response = await httpClient.PostAsync(_profileImageUploadUri, content);
   response.EnsureSuccessStatusCode();
}

这只会发送多部分/表单数据，但我希望多部分/混合在帖子的某个地方。

更新：好的，我知道了。

using (var content = new MultipartFormDataContent())
{
    var mixed = new MultipartContent("mixed")
    {
        CreateFileContent(imageStream, "image.jpg", "image/jpeg"),
        CreateFileContent(signatureStream, "image.jpg.sig", "application/octet-stream")
    };

    content.Add(mixed, "files");

    var response = await httpClient.PostAsync(_profileImageUploadUri, content);
    response.EnsureSuccessStatusCode();
}

private StreamContent CreateFileContent(Stream stream, string fileName, string contentType)
{
    var fileContent = new StreamContent(stream);
    fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("file") {FileName = fileName};
    fileContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);
    return fileContent;
}

这在钢丝鲨上看起来是正确的。但我看不到控制器中的文件。

[HttpPost]
public ActionResult UploadProfileImage(IEnumerable<HttpPostedFileBase> postedFiles)
{
    if(postedFiles == null)
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);

    // more code here
}

postedFiles 仍然为空。有什么想法吗？

Answer 1

成功了。但是行为很奇怪。

using (var content = new MultipartFormDataContent())
{
    content.Add(CreateFileContent(imageStream, "image.jpg", "image/jpeg"));
    content.Add(CreateFileContent(signatureStream, "image.jpg.sig", "application/octet-stream"));

    var response = await httpClient.PostAsync(_profileImageUploadUri, content);
    response.EnsureSuccessStatusCode();
}

private StreamContent CreateFileContent(Stream stream, string fileName, string contentType)
{
    var fileContent = new StreamContent(stream);
    fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") 
    { 
        Name = "\"files\"", 
        FileName = "\"" + fileName + "\""
    }; // the extra quotes are key here
    fileContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);            
    return fileContent;
}

[HttpPost]
public ActionResult UploadProfileImage(IList<HttpPostedFileBase> files)
{
    if(files == null || files.Count != 2)
        return new HttpStatusCodeResult(HttpStatusCode.BadRequest);

    // more code
}