Sers/dotnet/Library/Vit/Vit.Net.Http.FormFile/MultipartForm.cs

using System.Collections.Generic;
using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Net.Http.Headers;
using System.IO;
using System.Threading.Tasks;

namespace Vit.Net.Http.FormFile
{


    /*
     * https://www.cnblogs.com/liuxiaoji/p/10266609.html
     * 
        <ItemGroup>
        <PackageReference Include = "Microsoft.AspNetCore.Http" Version="2.2.2" />
        <PackageReference Include = "Microsoft.Net.Http.Headers" Version="2.2.8" />
        </ItemGroup>
    */



    public class FormFile
    {
        /// <summary>
        /// 文件在form中的name（如 "files"）
        /// </summary>
        public string formKey;
        /// <summary>
        /// 上传文件时的文件名称（含后缀 如 "user.jpg"）
        /// </summary>
        public string fileName;
        /// <summary>
        /// 文件的二进制正文内容
        /// </summary>
        public byte[] content;
    }

    /// <summary>
    /// 
    /// </summary>
    public class MultipartForm
    {
        public Dictionary<string,string> form { get; private set; }
        public List<FormFile> files { get; private set; }


        public MultipartForm(Stream Body, string ContentType)
        {
            ReadMultipartForm(this, Body, ContentType);
        }


        public MultipartForm(byte[] Body, string ContentType)
        {
            using (var stream = new MemoryStream(Body))
            {
                ReadMultipartForm(this, stream, ContentType);
            }
           
        }


        #region ReadMultipartForm
        private static async Task<MultipartForm> ReadMultipartForm(MultipartForm formData,Stream Body, string ContentType)
        {
            var boundary = HeaderUtilities.RemoveQuotes(MediaTypeHeaderValue.Parse(ContentType).Boundary).Value;
            var reader = new MultipartReader(boundary, Body);


            formData.files = new List<FormFile>();
            formData.form = new Dictionary<string, string>();
     


            MultipartSection section;
            while ((section = await reader.ReadNextSectionAsync()) != null)
            {        
                ContentDispositionHeaderValue contentDisposition = section.GetContentDispositionHeader();
                if (contentDisposition == null) continue;
             
                if (contentDisposition.IsFileDisposition())
                {
                    var file = section.AsFileSection();
                    byte[] buff;
                    using (var stream = new MemoryStream())
                    {
                        await section.Body.CopyToAsync(stream);
                        //await file.FileStream.CopyToAsync(stream);
                        buff = stream.ToArray();
                    }
                    formData.files.Add(new FormFile { formKey = file.Name, fileName = contentDisposition.FileName.ToString(), content = buff });
                }
                else if (contentDisposition.IsFormDisposition())
                {
                    var form = section.AsFormDataSection();
                    formData.form[form.Name] = await form.GetValueAsync();                     
                }
            }
            return formData;
        }
        #endregion
    }
}