data-transfer/SnapshotWinFormsApp/Tools/FileTools.cs

using SnapshotWinFormsApp.Entities.NewHotline;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Net.Http.Headers;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using File = SnapshotWinFormsApp.Entities.NewHotline.File;

namespace SnapshotWinFormsApp.Tools;

public class FileTools
{
    /// <summary>
    /// 下载网络文件并上传到文件服务器, 返回 File.Id
    /// </summary>
    /// <param name="file"></param>
    /// <param name="cancellationToken"></param>
    /// <returns></returns>
    public async Task<FileJson> GetNetworkFileAsync(string file, CancellationToken cancellationToken = default)
    {
        try
        {
            var fileBytes = await DownloadFileToMemoryAsync(file);
            if (fileBytes is null) return new FileJson();

            var uploadUrl = ConfigurationManager.AppSettings["FileServerUrl"] + "/file/upload?source=hotline";
            var match = Regex.Match(file, "[^/]+\\.[a-zA-Z0-9]+$").Value;
            var resultJson = await UploadFileFromMemoryAsync(fileBytes, match, uploadUrl);
            var result = resultJson.FromJson<ApiResponse<FileJson>>();
            var fileSplit = match.Split('.');
            var entity = new File()
            {
                Additions = result.Result.Id,
                FileName = result.Result.FileName,
                Path = result.Result.Path,
                AllPath = file,
                Type = fileSplit[1],
                Name = fileSplit[0],
            };
            return result.Result;
        }
        catch (Exception e)
        {
            var message = $"下载网络文件并上传到文件服务器失败: {e.Message}";
        }
        return new FileJson();
    }

    /// <summary>
    /// 下载文件, 返回字节
    /// </summary>
    /// <param name="url"></param>
    /// <returns></returns>
    private async Task<byte[]> DownloadFileToMemoryAsync(string url)
    {
        try
        {
            using var client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync(url);
            response.EnsureSuccessStatusCode();
            return await response.Content.ReadAsByteArrayAsync();

        }
        catch (Exception e)
        {
            var msg = e.Message;
        }
        finally
        {
        }
        return null;
    }

    public async Task<string> UploadFileFromMemoryAsync(byte[] fileBytes, string fileName, string uploadUrl)
    {
        using HttpClient client = new HttpClient();
        using var multipartContent = new MultipartFormDataContent();
        var fileContent = new ByteArrayContent(fileBytes);
        fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("image/jpeg");

        multipartContent.Add(fileContent, "fileData", fileName);

        HttpResponseMessage response = await client.PostAsync(uploadUrl, multipartContent);
        response.EnsureSuccessStatusCode();

        var result = await response.Content.ReadAsStringAsync();
        return result;
    }
}