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C#在.NET MVC中如何设计大附件上传的进度监控界面？

news 2026/5/12 16:14:53

开发者日记：2023年X月X日星期X 长沙晴

项目背景
今日正式启动客户的大文件传输系统项目，需求明确：支持20G文件/文件夹上传下载、跨平台（Windows/macOS/Linux）、全浏览器兼容（含IE8）、断点续传、保留文件夹层级结构。后端使用**.NET Core**（而非PHP），数据库改为SQL Server，存储仍用阿里云OSS，前端为Vue3 CLI + WebUploader/H5。客户强调高频文件夹上传场景，需极致优化用户体验。免费开源代码和7*24支持的压力依旧，但技术栈调整带来新挑战。

技术选型与调整

前端框架
- Vue3 CLI：维持组件化开发，但需适配IE8的Polyfill（如babel-polyfill）。
- WebUploader：核心上传组件，需深度定制文件夹解析逻辑。
- H5 File API：现代浏览器备用方案，IE8回退到Flash上传。
后端架构
- .NET Core：替代PHP，利用IFormFile处理分片，System.Data.SqlClient操作SQL Server。
- SQL Server：存储文件元数据（路径、分片状态、用户ID）。
核心难点升级
- 高频文件夹上传：需优化递归解析性能，避免前端卡顿。
- 断点续传稳定性：SQL Server事务保证分片记录一致性。
- IE8兼容性：Flash上传需处理跨域问题（crossdomain.xml）。

前端代码优化（Vue3 + WebUploader）

1. 强化文件夹上传逻辑

// src/components/FolderUploader.vueimport{ref,onMounted}from'vue';importWebUploaderfrom'webuploader';import'webuploader/dist/webuploader.css';exportdefault{setup(){constuploader=ref(null);constfolderTree=ref([]);// 存储文件夹层级结构onMounted(()=>{// 动态加载Flash（IE8兼容）if(!WebUploader.Uploader.support('HTML5')){WebUploader.Uploader.register({name:'flash',fn:()=>'/assets/Uploader.swf'});}uploader.value=newWebUploader.Uploader({swf:'/assets/Uploader.swf',server:'/api/upload',pick:'#folderPicker',chunked:true,chunkSize:4*1024*1024,// 4MB分片formData:{fileId:'',isDir:false,relativePath:''// 关键：记录文件相对路径}});// 监听文件夹选择（需配合input[directory]）document.getElementById('folderInput').addEventListener('change',(e)=>{constitems=e.target.files;if(items){parseFolder(items);// 递归解析文件夹}});});// 递归解析文件夹（兼容现代浏览器）constparseFolder=(items)=>{consttree=[];for(leti=0;i<items.length;i++){constfile=items[i];constpath=file.webkitRelativePath||file.name;// 相对路径constsegments=path.split('/');// 构建树形结构letcurrentLevel=tree;segments.slice(0,-1).forEach(segment=>{letdir=currentLevel.find(item=>item.name===segment);if(!dir){dir={name:segment,type:'directory',children:[]};currentLevel.push(dir);}currentLevel=dir.children;});// 添加文件节点currentLevel.push({name:segments.pop(),type:'file',file:file,relativePath:path});}folderTree.value=tree;uploadFolder(tree);};// 上传文件夹内容constuploadFolder=(tree)=>{tree.forEach(node=>{if(node.type==='directory'){uploadFolder(node.children);// 递归上传子目录}else{constformData=uploader.value.option('formData');formData.relativePath=node.relativePath;uploader.value.addFile(node.file,node.relativePath);}});};return{uploader,folderTree};}};

2. IE8兼容性处理

后端代码实现（.NET Core + SQL Server）

1. 分片上传接口

// Controllers/UploadController.csusingMicrosoft.AspNetCore.Mvc;usingSystem.Data.SqlClient;usingSystem.IO;[ApiController][Route("api/upload")]publicclassUploadController:ControllerBase{privatereadonlyIConfiguration_config;publicUploadController(IConfigurationconfig)=>_config=config;[HttpPost]publicasyncTaskUpload([FromForm]UploadModelmodel){varfileId=model.FileId??Guid.NewGuid().ToString();vartempDir=Path.Combine("/tmp/uploads",fileId);Directory.CreateDirectory(tempDir);// 保存分片varchunkPath=Path.Combine(tempDir,$"chunk_{model.ChunkIndex}");using(varstream=newFileStream(chunkPath,FileMode.Create)){awaitmodel.File.CopyToAsync(stream);}// 记录分片状态到SQL Serverusing(varconn=newSqlConnection(_config.GetConnectionString("Default"))){awaitconn.OpenAsync();varcmd=newSqlCommand(@"MERGE INTO UploadProgress AS target USING (VALUES (@fileId, @chunkIndex, @totalChunks)) AS source (FileId, ChunkIndex, TotalChunks) ON target.FileId = source.FileId AND target.ChunkIndex = source.ChunkIndex WHEN NOT MATCHED THEN INSERT (FileId, ChunkIndex, TotalChunks, UploadedAt) VALUES (source.FileId, source.ChunkIndex, source.TotalChunks, GETDATE());",conn);cmd.Parameters.AddWithValue("@fileId",fileId);cmd.Parameters.AddWithValue("@chunkIndex",model.ChunkIndex);cmd.Parameters.AddWithValue("@totalChunks",model.TotalChunks);awaitcmd.ExecuteNonQueryAsync();}// 如果是最后一块，合并并上传OSSif(model.ChunkIndex==model.TotalChunks-1){varfinalPath=Path.Combine(tempDir,"final_file");using(varoutput=System.IO.File.Create(finalPath)){for(inti=0;i<model.TotalChunks;i++){varchunk=System.IO.File.ReadAllBytes(Path.Combine(tempDir,$"chunk_{i}"));awaitoutput.WriteAsync(chunk,0,chunk.Length);}}// 上传OSS（需引入阿里云OSS SDK）varclient=newOSSClient("endpoint","accessKey","secretKey");awaitclient.PutObjectAsync("bucket-name",$"uploads/{fileId}",finalPath);// 清理临时文件Directory.Delete(tempDir,true);}returnOk(new{success=true,fileId});}}publicclassUploadModel{publicIFormFileFile{get;set;}publicstringFileId{get;set;}publicintChunkIndex{get;set;}publicintTotalChunks{get;set;}publicstringRelativePath{get;set;}// 文件夹层级路径}

2. SQL Server表结构

CREATETABLEUploadProgress(IdINTIDENTITY(1,1)PRIMARYKEY,FileId NVARCHAR(64)NOTNULL,ChunkIndexINTNOTNULL,TotalChunksINTNOTNULL,UploadedAt DATETIME2DEFAULTGETDATE(),UNIQUE(FileId,ChunkIndex));

断点续传实现

1. 前端恢复逻辑

// 检查未完成上传constcheckResume=async(fileId)=>{constres=awaitfetch(`/api/upload/progress?fileId=${fileId}`);constdata=awaitres.json();if(data.completedChunks<data.totalChunks){uploader.value.option('formData',{fileId,chunk:data.completedChunks});uploader.value.upload();}};// 本地存储fileId（即使浏览器关闭）window.addEventListener('beforeunload',()=>{if(uploader.value.getFiles().length>0){localStorage.setItem('lastUploadId',uploader.value.option('formData').fileId);}});

2. 后端进度查询

[HttpGet("progress")]publicasyncTaskGetProgress(stringfileId){using(varconn=newSqlConnection(_config.GetConnectionString("Default"))){awaitconn.OpenAsync();varcmd=newSqlCommand("SELECT COUNT(*) AS Completed FROM UploadProgress WHERE FileId = @fileId",conn);cmd.Parameters.AddWithValue("@fileId",fileId);varcount=(int)awaitcmd.ExecuteScalarAsync();returnOk(new{completedChunks=count});}}