009_DI-Elec/newFront/c#前端/SWS.CAD/Services/AnnexesService.cs

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using SWS.CAD.Helper;
using SWS.CAD.Models;
using SWS.CAD.Models.NoEntity;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Security.Policy;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Web;

namespace SWS.CAD.Services
{
    public class AnnexesService : HttpService
    {

        public AnnexesService() : base()
        {

        }
        /// <summary>
        /// 查询文件实体
        /// </summary> 
        /// <returns></returns>
        public async Task<annexesfile> GetAnnexesFile(string folderId)
        {
            var res = await this.GetAsync<annexesfile>($"AnnexesApi/GetFileEntity?projectId={GlobalObject.curProject.ProjectId}&folderId={folderId}");

            if (res.code == 200)
            {

                return res.data;
            }
            else
            {
                return null;//ERROR INFO
            }
        }
        /// <summary>
        /// 上传本地文件到server
        /// </summary>
        /// <param name="fullFilePath">完整的路径</param>
        /// <param name="fileName">带后缀</param>
        /// <returns>返回新的一个folder ID</returns>
        public async Task<string> UploadFile(string fullFilePath, string fileName)
        {
            using (var stream = new FileStream(fullFilePath, FileMode.Open, FileAccess.Read))
            {
                var res = await this.PostFileAsync<string>($"AnnexesApi/UploadFile", stream, fileName);
                return res;//new Folder Id 
            }
        }

        /// <summary>
        /// 下载文件
        /// </summary>
        /// <param name="url">文件下载地址</param>
        /// <param name="savePath">本地保存路径</param>
        /// <param name="progress">进度报告接口（可选）</param>
        /// <param name="cancellationToken">取消令牌（可选）</param>
        /// <returns>返回空字符串认为是OK的</returns>
        public async Task<string> DownloadFile(
            string savePath, string fileId,
            IProgress<double> progress = null,
            CancellationToken cancellationToken = default)
        {
            try
            {
                var p = Path.GetDirectoryName(savePath);
                if (!Directory.Exists(p))
                    Directory.CreateDirectory(p);
                string url = $"AnnexesApi/DownFile?fileId={fileId}";
                // 发送请求并获取响应
                using (var response = await GlobalObject.client.GetAsync(
                    url,
                    HttpCompletionOption.ResponseHeadersRead,
                    cancellationToken))
                {

                    if (response.StatusCode != HttpStatusCode.OK)
                    {
                        string errorMsg = $"服务器地址 [{url}] 文件下载失败, 返回HTTP代码：" + response.StatusCode;
                        LoggerHelper.Current.Error(errorMsg);
                        throw new HttpRequestException(errorMsg);
                    }
                    response.EnsureSuccessStatusCode(); // 确保响应成功
                    var result = await response.Content.ReadAsStringAsync();
                    learunHttpRes<object> resultObj = null;
                    try
                    {
                        resultObj = JsonConvert.DeserializeObject<learunHttpRes<object>>(result);
                    }
                    catch (JsonException)
                    {
                        //对下载文件来说，如果正常的话，这里反而是合理的，因为返回的就是stream的东西，不能被解析为learunHttpRes
                        await HandleStreamAsync();
                        return "";
                    }

                    if (resultObj.code != 200)
                    {
                        switch (resultObj.code)
                        {
                            case 400:
                            case 500:
                                return resultObj.info.ToString(); //业务错误，不是http本质错误                                
                            default:
                                string errorMsg = $"服务器地址 [{url}] Get失败, 返回自定义代码：" + resultObj.code;
                                LoggerHelper.Current.Error(errorMsg);
                                throw new HttpRequestException(errorMsg);
                        }

                    }
                    else
                    { 
                        await HandleStreamAsync();
                        return "";
                      
                    } 

                    async Task HandleStreamAsync()
                    {
                        #region core
                        // 获取文件总大小（可能为 null）
                        var totalBytes = response.Content.Headers.ContentLength;

                        // 创建文件流
                        using (var contentStream = await response.Content.ReadAsStreamAsync())
                        using (var fileStream = new FileStream(
                            savePath,
                            FileMode.Create,
                            FileAccess.Write,
                            FileShare.None,
                            bufferSize: 8192,
                            useAsync: true))
                        {
                            var buffer = new byte[8192];
                            var totalBytesRead = 0L;
                            var bytesRead = 0;

                            // 分块读取并写入文件
                            while ((bytesRead = await contentStream.ReadAsync(
                                buffer,
                                0,
                                buffer.Length,
                                cancellationToken)) > 0)
                            {
                                await fileStream.WriteAsync(
                                    buffer,
                                    0,
                                    bytesRead,
                                    cancellationToken);

                                totalBytesRead += bytesRead;

                                // 报告进度（如果有总大小）
                                if (totalBytes.HasValue)
                                {
                                    var percent = (double)totalBytesRead / totalBytes.Value * 100;
                                    progress?.Report(percent);
                                }
                            }
                        }
                        #endregion
                    }

                }
            }
            catch (HttpRequestException ex)
            {
                return ex.Message;
                //throw new Exception($"下载请求失败: {ex.Message}");
            }
            catch (TaskCanceledException ex2)
            {
                return ex2.Message;
                // 取消操作时删除已下载的部分文件
                //if (File.Exists(savePath)) File.Delete(savePath);
                //throw;
            }
            catch (Exception ex3)
            {
                return ex3.Message;
                //throw new Exception($"下载失败: {ex.Message}");
            }


        }
    }
}