WebAPI文件上传-无需将文件写入磁盘 [英] WebAPI File Uploading - Without writing files to disk

问题描述

有关处理使用FormData上传到ASP.NET WebAPI处理程序的文件的所有文档/教程/问题，均使用MultipartFormDataStreamProvider处理多部分流以将其拆分为相关的表单字段和文件.

All the documentation / tutorials / questions about processing a file uploaded using FormData to a ASP.NET WebAPI handler use MultipartFormDataStreamProvider to process the multipart stream to split it into the relevant form fields and files.

var root = HttpContext.Current.Server.MapPath("~/App_Data");
var provider = new MultipartFormDataStreamProvider(root);

await Request.Content.ReadAsMultipartAsync(provider);

foreach (MultipartFileData file in provider.FileData)
{
   // File
}

但是，文件在处理过程中会自动写入目录中.

However, the files are automatically written to a directory during processsing.

当我只能使用HttpContext.Current.Request.Files[0].InputStream直接在内存中访问给定的文件流时，似乎很麻烦.

It seems a lot of hassle when I could just use HttpContext.Current.Request.Files[0].InputStream to access a given file stream directly in memory.

WebAPI如何直接访问文件流而无需使用MultipartFormDataStreamProvider的IO开销?

How can WebAPI just access the file stream directly without the IO overhead of using MultipartFormDataStreamProvider?

官方教程: http://www.asp .net/web-api/overview/advanced/sending-html-form-data，-part-2

推荐答案

已解决:

使用现有的简单 MultipartMemoryStreamProvider .不需要自定义类或提供程序.这与重复问题不同，该问题通过编写解决方案定制提供商.

Use the existing simple MultipartMemoryStreamProvider. No custom classes or providers required. This differers from the duplicate question which solved the solution by writing a custom provider.

然后按如下方式在WebAPI处理程序中使用它:

Then use it in a WebAPI handler as so:

public async Task<IHttpActionResult> UploadFile()
{
    if (!Request.Content.IsMimeMultipartContent())
    {
        return StatusCode(HttpStatusCode.UnsupportedMediaType);
    }        

    var filesReadToProvider = await Request.Content.ReadAsMultipartAsync();

    foreach (var stream in filesReadToProvider.Contents)
    {
        var fileBytes = await stream.ReadAsByteArrayAsync();
    }
}

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