C # HttpClient 4.5 multipart/form-data load

有人知道如何在.Net 4.5中使用 HttpClient和 multipart/form-data上传吗？

我在网上找不到任何例子。

295235 次浏览
小开

它的工作原理大致如下(例如使用 image/jpg 文件) :

async public Task<HttpResponseMessage> UploadImage(string url, byte[] ImageData)
{
var requestContent = new MultipartFormDataContent();
//    here you can specify boundary if you need---^
var imageContent = new ByteArrayContent(ImageData);
imageContent.Headers.ContentType =
MediaTypeHeaderValue.Parse("image/jpeg");


requestContent.Add(imageContent, "image", "image.jpg");


return await client.PostAsync(url, requestContent);
}

(您可以使用任何 requestContent.Add()，请查看 HttpContent 的后代以查看可以传入的可用类型)

完成后，您将在 HttpResponseMessage.Content中找到可以使用 HttpContent.ReadAs*Async的响应内容。

小开
最佳答案

我的结果是这样的:

public static async Task<string> Upload(byte[] image)
{
using (var client = new HttpClient())
{
using (var content =
new MultipartFormDataContent("Upload----" + DateTime.Now.ToString(CultureInfo.InvariantCulture)))
{
content.Add(new StreamContent(new MemoryStream(image)), "bilddatei", "upload.jpg");


using (
var message =
await client.PostAsync("http://www.directupload.net/index.php?mode=upload", content))
{
var input = await message.Content.ReadAsStringAsync();


return !string.IsNullOrWhiteSpace(input) ? Regex.Match(input, @"http://\w*\.directupload\.net/images/\d*/\w*\.[a-z]{3}").Value : null;
}
}
}
}
小开

这是如何使用 MultipartFormDataContent 通过 HTTPClient 发布字符串和文件流的示例。内容处理和内容类型需要为每个 HTTPContent 指定:

下面是我的例子，希望对你有所帮助:

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");
//Content-Disposition: form-data; name="file"; filename="C:\B2BAssetRoot\files\596090\596090.1.mp4";
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<HttpResponseMessage> message = client.PostAsync("http://api.brightcove.com/services/post", content);


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

这里有一个完整的例子，我的工作。在请求中的 boundary值是由.NET 自动添加。

var url = "http://localhost/api/v1/yourendpointhere";
var filePath = @"C:\path\to\image.jpg";


HttpClient httpClient = new HttpClient();
MultipartFormDataContent form = new MultipartFormDataContent();


FileStream fs = File.OpenRead(filePath);
var streamContent = new StreamContent(fs);


var imageContent = new ByteArrayContent(streamContent.ReadAsByteArrayAsync().Result);
imageContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");


form.Add(imageContent, "image", Path.GetFileName(filePath));
var response = httpClient.PostAsync(url, form).Result;
小开

试试这个对我有用。

private static async Task<object> Upload(string actionUrl)
{
Image newImage = Image.FromFile(@"Absolute Path of image");
ImageConverter _imageConverter = new ImageConverter();
byte[] paramFileStream= (byte[])_imageConverter.ConvertTo(newImage, typeof(byte[]));


var formContent = new MultipartFormDataContent
{
// Send form text values here
{new StringContent("value1"),"key1"},
{new StringContent("value2"),"key2" },
// Send Image Here
{new StreamContent(new MemoryStream(paramFileStream)),"imagekey","filename.jpg"}
};


var myHttpClient = new HttpClient();
var response = await myHttpClient.PostAsync(actionUrl.ToString(), formContent);
string stringContent = await response.Content.ReadAsStringAsync();


return response;
}
小开

下面是另一个关于如何使用 HttpClient上传 multipart/form-data的示例。

它将文件上传到 REST API，并包括文件本身(例如 JPG)和其他 API 参数。文件通过 FileStream直接从本地磁盘上传。

请参阅 给你了解完整的示例，其中包括其他特定于 API 的逻辑。

public static async Task UploadFileAsync(string token, string path, string channels)
{
// we need to send a request with multipart/form-data
var multiForm = new MultipartFormDataContent();


// add API method parameters
multiForm.Add(new StringContent(token), "token");
multiForm.Add(new StringContent(channels), "channels");


// add file and directly upload it
FileStream fs = File.OpenRead(path);
multiForm.Add(new StreamContent(fs), "file", Path.GetFileName(path));


// send request to API
var url = "https://slack.com/api/files.upload";
var response = await client.PostAsync(url, multiForm);
}
小开 
public async Task<object> PassImageWithText(IFormFile files)
{
byte[] data;
string result = "";
ByteArrayContent bytes;


MultipartFormDataContent multiForm = new MultipartFormDataContent();


try
{
using (var client = new HttpClient())
{
using (var br = new BinaryReader(files.OpenReadStream()))
{
data = br.ReadBytes((int)files.OpenReadStream().Length);
}


bytes = new ByteArrayContent(data);
multiForm.Add(bytes, "files", files.FileName);
multiForm.Add(new StringContent("value1"), "key1");
multiForm.Add(new StringContent("value2"), "key2");


var res = await client.PostAsync(_MEDIA_ADD_IMG_URL, multiForm);
}
}
catch (Exception e)
{
throw new Exception(e.ToString());
}


return result;
}
小开 
X509Certificate clientKey1 = null;
clientKey1 = new X509Certificate(AppSetting["certificatePath"],
AppSetting["pswd"]);
string url = "https://EndPointAddress";
FileStream fs = File.OpenRead(FilePath);
var streamContent = new StreamContent(fs);


var FileContent = new ByteArrayContent(streamContent.ReadAsByteArrayAsync().Result);
FileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("ContentType");
var handler = new WebRequestHandler();




handler.ClientCertificateOptions = ClientCertificateOption.Manual;
handler.ClientCertificates.Add(clientKey1);
handler.ServerCertificateValidationCallback = (httpRequestMessage, cert, cetChain, policyErrors) =>
{
return true;
};




using (var client = new HttpClient(handler))
{
// Post it
HttpResponseMessage httpResponseMessage = client.PostAsync(url, FileContent).Result;


if (!httpResponseMessage.IsSuccessStatusCode)
{
string ss = httpResponseMessage.StatusCode.ToString();
}
}
小开

我添加了一个代码片段，它显示了如何发布一个文件到一个 API，已经通过 DELETEhttp 动词公开。使用 DELETEhttp 谓词上载文件并不常见，但允许这样做。我假定使用 WindowsNTLM 身份验证来授权调用。

人们可能会面临的问题是，HttpClient.DeleteAsync方法的所有重载都没有 HttpContent的参数，就像我们在 PostAsync方法中得到的那样

var requestUri = new Uri("http://UrlOfTheApi");
using (var streamToPost = new MemoryStream("C:\temp.txt"))
using (var fileStreamContent = new StreamContent(streamToPost))
using (var httpClientHandler = new HttpClientHandler() { UseDefaultCredentials = true })
using (var httpClient = new HttpClient(httpClientHandler, true))
using (var requestMessage = new HttpRequestMessage(HttpMethod.Delete, requestUri))
using (var formDataContent = new MultipartFormDataContent())
{
formDataContent.Add(fileStreamContent, "myFile", "temp.txt");
requestMessage.Content = formDataContent;
var response = httpClient.SendAsync(requestMessage).GetAwaiter().GetResult();
    

if (response.IsSuccessStatusCode)
{
// File upload was successfull
}
else
{
var erroResult = response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
throw new Exception("Error on the server : " + erroResult);
}
}

在 C # 文件的顶部需要以下名称空间:

using System;
using System.Net;
using System.IO;
using System.Net.Http;

P.S. 在上面的代码片段中，您看到了许多使用块(IDisposable 模式) ，这些块看起来不太干净。遗憾的是，using结构的语法不支持在单个语句中初始化多个变量。

小开

示例与预加载器 Dotnet 3.0核心

ProgressMessageHandler processMessageHander = new ProgressMessageHandler();


processMessageHander.HttpSendProgress += (s, e) =>
{
if (e.ProgressPercentage > 0)
{
ProgressPercentage = e.ProgressPercentage;
TotalBytes = e.TotalBytes;
progressAction?.Invoke(progressFile);
}
};


using (var client = HttpClientFactory.Create(processMessageHander))
{
var uri = new Uri(transfer.BackEndUrl);
client.DefaultRequestHeaders.Authorization =
new AuthenticationHeaderValue("Bearer", AccessToken);


using (MultipartFormDataContent multiForm = new MultipartFormDataContent())
{
multiForm.Add(new StringContent(FileId), "FileId");
multiForm.Add(new StringContent(FileName), "FileName");
string hash = "";


using (MD5 md5Hash = MD5.Create())
{
var sb = new StringBuilder();
foreach (var data in md5Hash.ComputeHash(File.ReadAllBytes(FullName)))
{
sb.Append(data.ToString("x2"));
}
hash = result.ToString();
}
multiForm.Add(new StringContent(hash), "Hash");


using (FileStream fs = File.OpenRead(FullName))
{
multiForm.Add(new StreamContent(fs), "file", Path.GetFileName(FullName));
var response = await client.PostAsync(uri, multiForm);
progressFile.Message = response.ToString();


if (response.IsSuccessStatusCode) {
progressAction?.Invoke(progressFile);
} else {
progressErrorAction?.Invoke(progressFile);
}
response.EnsureSuccessStatusCode();
}
}
}

提交答案