.Net Core实现图片文件上传下载功能

来源：动视网责编：小采时间：2020-11-27 22:35:41

.Net Core实现图片文件上传下载功能

.Net Core实现图片文件上传下载功能:当下.Net Core项目可是如雨后春笋一般发展起来，作为.Net大军中的一员，我热忱地拥抱了.Net Core并且积极使用其进行业务的开发，我们先介绍下.Net Core项目下实现文件上传下载接口。一、开发环境毋庸置疑，宇宙第一IDE VisualStudio 2017

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导读.Net Core实现图片文件上传下载功能:当下.Net Core项目可是如雨后春笋一般发展起来，作为.Net大军中的一员，我热忱地拥抱了.Net Core并且积极使用其进行业务的开发，我们先介绍下.Net Core项目下实现文件上传下载接口。一、开发环境毋庸置疑，宇宙第一IDE VisualStudio 2017

当下.Net Core项目可是如雨后春笋一般发展起来，作为.Net大军中的一员，我热忱地拥抱了.Net Core并且积极使用其进行业务的开发，我们先介绍下.Net Core项目下实现文件上传下载接口。

一、开发环境

毋庸置疑，宇宙第一IDE VisualStudio 2017

二、项目结构

FilesController 文件上传下载控制器

PictureController 图片上传下载控制器

Return_Helper_DG 返回值帮助类

三、关键代码

1、首先我们来看Startup.cs 这个是我们的程序启动配置类，在这里我们进行一系列的配置。

跨域配置：

当然跨域少不了dll的引用，我们使用Nuget引用相关的引用包

服务器资源路径置换，这样可以防止客户端猜测服务端文件路径，制造一个虚拟的隐射进行访问，提高了安全性。

Startup.cs的完整代码如下：

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Logging;
using System.IO;

namespace QX_Core.FilesCenter
{
 public class Startup
 {
 public Startup(IHostingEnvironment env)
 {
 var builder = new ConfigurationBuilder()
 .SetBasePath(env.ContentRootPath)
 .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
 .AddEnvironmentVariables();
 Configuration = builder.Build();
 }

 public IConfigurationRoot Configuration { get; }

 // This method gets called by the runtime. Use this method to add services to the container.
 public void ConfigureServices(IServiceCollection services)
 {
 // Add framework services.
 services.AddMvc();
 #region CORS
 services.AddCors(options =>
 {
 options.AddPolicy("AllowSpecificOrigin",
 builder => builder.WithOrigins("http://localhost:3997").AllowAnyHeader().AllowAnyOrigin().AllowAnyMethod());
 });
 #endregion
 }

 // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
 public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
 {
 //loggerFactory.AddConsole(Configuration.GetSection("Logging"));
 //loggerFactory.AddDebug();

 app.UseMvc();
 // Shows UseCors with named policy.
 app.UseCors("AllowSpecificOrigin");

 app.UseStaticFiles(new StaticFileOptions()
 {
 FileProvider = new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), @"wwwroot/Files")),
 RequestPath = new PathString("/src")
 });
 }
 }
}

2、Return_Helper_DG类用户设置一个统一的返回值反馈到客户端
Return_Helper_DG类的代码如下：

using System.Net;
/**
* author:qixiao
* create:2017-5-19 15:15:05
* */
namespace QX_Core.FilesCenter.QX_Core.Helper
{
 public abstract class Return_Helper_DG
 {
 public static object IsSuccess_Msg_Data_HttpCode(bool isSuccess, string msg, dynamic data, HttpStatusCode httpCode = HttpStatusCode.OK)
 {
 return new { isSuccess = isSuccess, msg = msg, httpCode = httpCode, data = data };
 }
 public static object Success_Msg_Data_DCount_HttpCode(string msg, dynamic data = null, int dataCount = 0, HttpStatusCode httpCode = HttpStatusCode.OK)
 {
 return new { isSuccess = true, msg = msg, httpCode = httpCode, data = data, dataCount = dataCount };
 }
 public static object Error_Msg_Ecode_Elevel_HttpCode(string msg, int errorCode = 0, int errorLevel = 0, HttpStatusCode httpCode = HttpStatusCode.InternalServerError)
 {
 return new { isSuccess = false, msg = msg, httpCode = httpCode, errorCode = errorCode, errorLevel = errorLevel };
 }
 }
}

3、FilesController是我们的文件上传控制器接口，这里定义了对上传的文件的接收操作，并且在控制器上启用跨域配置

using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;
using QX_Core.FilesCenter.QX_Core.Helper;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace QX_Core.FilesCenter.Controllers
{
 //[Produces("application/json")]
 [Route("api/[controller]")]
 [EnableCors("AllowSpecificOrigin")]
 public class FilesController : Controller
 {
 private IHostingEnvironment hostingEnv;

 public FilesController(IHostingEnvironment env)
 {
 this.hostingEnv = env;
 }

 [HttpPost]
 public IActionResult Post()
 {
 var files = Request.Form.Files;
 long size = files.Sum(f => f.Length);

 //size > 100MB refuse upload !
 if (size > 104857600)
 {
 return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("files total size > 100MB , server refused !"));
 }

 List<string> filePathResultList = new List<string>();

 foreach (var file in files)
 {
 var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');

 string filePath = hostingEnv.WebRootPath + $@"\Files\Files\";

 if (!Directory.Exists(filePath))
 {
 Directory.CreateDirectory(filePath);
 }

 fileName = Guid.NewGuid() + "." + fileName.Split('.')[1];

 string fileFullName = filePath + fileName;

 using (FileStream fs = System.IO.File.Create(fileFullName))
 {
 file.CopyTo(fs);
 fs.Flush();
 }
 filePathResultList.Add($"/src/Files/{fileName}");
 }

 string message = $"{files.Count} file(s) /{size} bytes uploaded successfully!";

 return Json(Return_Helper_DG.Success_Msg_Data_DCount_HttpCode(message, filePathResultList, filePathResultList.Count));
 }

 }
}

在上述的代码中，我们对上传的文件的大小进行了限制，并且对文件的大小进行反馈。

4、PictureController 图片上传控制器接口，类似于文件，不过对上传的图片类型进行了校验和限制

using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;
using QX_Core.FilesCenter.QX_Core.Helper;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace QX_Core.FilesCenter.Controllers
{
 //[Produces("application/json")]
 [Route("api/[controller]")]
 [EnableCors("AllowSpecificOrigin")]
 public class PicturesController : Controller
 {
 private IHostingEnvironment hostingEnv;

 string[] pictureFormatArray = { "png", "jpg", "jpeg", "bmp", "gif","ico", "PNG", "JPG", "JPEG", "BMP", "GIF","ICO" };

 public PicturesController(IHostingEnvironment env)
 {
 this.hostingEnv = env;
 }

 [HttpPost]
 public IActionResult Post()
 {
 var files = Request.Form.Files;
 long size = files.Sum(f => f.Length);

 //size > 100MB refuse upload !
 if (size > 104857600)
 {
 return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("pictures total size > 100MB , server refused !"));
 }

 List<string> filePathResultList = new List<string>();

 foreach (var file in files)
 {
 var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');

 string filePath = hostingEnv.WebRootPath + $@"\Files\Pictures\";

 if (!Directory.Exists(filePath))
 {
 Directory.CreateDirectory(filePath);
 }

 string suffix = fileName.Split('.')[1];

 if (!pictureFormatArray.Contains(suffix))
 {
 return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("the picture format not support ! you must upload files that suffix like 'png','jpg','jpeg','bmp','gif','ico'."));
 }

 fileName = Guid.NewGuid() + "." + suffix;

 string fileFullName = filePath + fileName;

 using (FileStream fs = System.IO.File.Create(fileFullName))
 {
 file.CopyTo(fs);
 fs.Flush();
 }
 filePathResultList.Add($"/src/Pictures/{fileName}");
 }

 string message = $"{files.Count} file(s) /{size} bytes uploaded successfully!";

 return Json(Return_Helper_DG.Success_Msg_Data_DCount_HttpCode(message, filePathResultList, filePathResultList.Count));
 }

 }
}

到此，我们的文件图片上传代码已经全部完成，下面我们对文件上传的客户端进行实现

四、客户端的实现

客户端我们很简单地用jQuery Ajax的方式进行图片文件的提交，客户端代码的实现：

<!doctype>

<head>
 <script src="jquery-3.2.0.min.js"></script>
 <script>
 $(document).ready(function () {
 var appDomain = "http://localhost:53972/";
 $("#btn_fileUpload").click(function () {
 var fileUpload = $("#files").get(0);
 var files = fileUpload.files;
 var data = new FormData();
 for (var i = 0; i < files.length; i++) {
 data.append(files[i].name, files[i]);
 }
 $.ajax({
 type: "POST",
 url: appDomain+'api/Pictures',
 contentType: false,
 processData: false,
 data: data,
 success: function (data) {
 console.log(JSON.stringify(data));
 },
 error: function () {
 console.log(JSON.stringify(data));
 }
 });
 });
 //end click


 })
 </script>
</head>
<title></title>

<body>
 <article>
 <header>
 <h2>article-form</h2>
 </header>
 <p>
 <form id="uploadForm" enctype="multipart/form-data">
 <input type="file" id="files" name="files" placeholder="file" multiple>file-multiple属性可以选择多项<br><br>
 <input type="button" id="btn_fileUpload" value="fileUpload">
 </form>
 </p>
 </article>
</body>

五、代码测试

1.启动服务器