.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。

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));