.Net Core 图片文件上传下载

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。

GitHub源码地址 https://github.com/sevenTiny/QX_Core.FilesCenter

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

我们可以看到一个控制台和一个web自动启动，并且web显示默认的Values控制器的请求返回值。

2.图片上传

我们使用ajax的方式进行图片的上传操作，打开测试web页面，并且选择图片，点击上传，查看控制台返回的结果：

可以看到，一张图片上传成功！

 输入返回的地址，我们可以看到成功访问到了图片，特别注意这里服务器路径的改变：

---

多图片上传：

可见，多图片上传没有任何问题！

---

同样进行文件上传的测试：

 

同样，文件上传也没有任何问题！

六、总结

至此，我们已经实现了预期的.Net Core图片文件上传的全部功能！

GitHub源码地址 https://github.com/sevenTiny/QX_Core.FilesCenter