c#服务端图片打包下载
标签：for json app current result delete serial max-age invoke
一，设计多图片打包下载逻辑：
1，如果是要拉取腾讯云等资源服务器的图片，
2，我们先把远程图片拉取到本地的临时文件夹，
3，然后压缩临时文件夹，
4，压缩完删除临时文件夹，
5，返回压缩完给用户，
6，用户就去请求下载接口，当下载完后，删除压缩包
二，如下代码，ImageUtil
using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Web;
namespace Common
{
///
/// 要引用
/// System.IO.Compression.FileSystem
/// System.IO.Compression
///
public static class ImageUtil
{
#region 图片打包下载
///
/// 下载图片到本地，压缩
///
/// 图片列表
/// 要压缩文档的路径
/// 压缩后生成文档保存路径
///
public static bool ImagePackZip(Liststring> urlList, string curDirName, string curFileName)
{
return CommonException(() =>
{
//1.新建文件夹
if (!Directory.Exists(curDirName))
Directory.CreateDirectory(curDirName);
//2.下载文件到服务器临时目录
foreach (var url in urlList)
{
DownPicToLocal(url, curDirName + "\\");
Thread.Sleep(60);//加个延时，避免上一张图还没下载完就执行下一张图的下载操作
}
//3.压缩文件夹
if (!File.Exists(curFileName))
ZipFile.CreateFromDirectory(curDirName, curFileName); //压缩
//异步删除压缩前，下载的临时文件
Task.Run(() =>
{
if (Directory.Exists(curDirName))
Directory.Delete(curDirName, true);
});
return true;
});
}
///
/// 下载压缩包
///
/// 目标临时文件地址
/// 文件名
public static bool DownePackZip(string targetfile, string filename)
{
return CommonException(() =>
{
FileInfo fileInfo = new FileInfo(targetfile);
HttpResponse rs = System.Web.HttpContext.Current.Response;
rs.Clear();
rs.ClearContent();
rs.ClearHeaders();
rs.AddHeader("Content-Disposition", "attachment;filename=" + $"{filename}");
rs.AddHeader("Content-Length", fileInfo.Length.ToString());
rs.AddHeader("Content-Transfer-Encoding", "binary");
rs.AddHeader("Pragma", "public");//这两句解决https的cache缓存默认不给权限的问题
rs.AddHeader("Cache-Control", "max-age=0");
rs.ContentType = "application/octet-stream";
rs.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
rs.WriteFile(fileInfo.FullName);
rs.Flush();
rs.End();
return true;
});
}
///
/// 下载一张图片到本地
///
///
public static bool DownPicToLocal(string url, string localpath)
{
return CommonException(() =>
{
string fileprefix = DateTime.Now.ToString("yyyyMMddhhmmssfff");
var filename = $"{fileprefix}.jpg";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Timeout = 60000;
WebResponse response = request.GetResponse();
using (Stream reader = response.GetResponseStream())
{
FileStream writer = new FileStream(localpath + filename, FileMode.OpenOrCreate, FileAccess.Write);
byte[] buff = new byte[512];
int c = 0; //实际读取的字节数
while ((c = reader.Read(buff, 0, buff.Length)) > 0)
{
writer.Write(buff, 0, c);
}
writer.Close();
writer.Dispose();
reader.Close();
reader.Dispose();
}
response.Close();
response.Dispose();
return true;
});
}
///
/// 公用捕获异常
///
///
///
private static bool CommonException(Funcbool> func)
{
try
{
return func.Invoke();
}
catch (Exception ex)
{
return false;
}
}
#endregion
}
}
三，测试MVC代码
using Common;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Web.Mvc;
namespace PackImageZip.Controllers
{
public class HomeController : Controller
{
private static object obj = new object();
public ActionResult Contact()
{
///锁，多文件请求打包，存在并发情况
lock (obj)
{
var DownPicpath = System.Web.HttpContext.Current.Server.MapPath("/DownPicPackge");//服务器临时文件目录
string curFileName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".zip";
///多次请求文件名一样，睡眠一下
Thread.Sleep(2000);
////保存拉取服务器图片文件夹
string curDirName = $"/{DateTime.Now.ToString("yyyyMMddHHmmssfff")}/";
Liststring> urlList = new Liststring>();
urlList.Add("https://cdn.duitang.com/uploads/item/201409/08/20140908155026_RdUwH.thumb.700_0.jpeg");
urlList.Add("https://cdn.duitang.com/uploads/item/201409/08/20140908155026_RdUwH.thumb.700_0.jpeg");
urlList.Add("https://cdn.duitang.com/uploads/item/201409/08/20140908155026_RdUwH.thumb.700_0.jpeg");
urlList.Add("https://cdn.duitang.com/uploads/item/201409/08/20140908155026_RdUwH.thumb.700_0.jpeg");
var isOk = ImageUtil.ImagePackZip(urlList, DownPicpath + curDirName, $"{DownPicpath}/{curFileName}");
var json = JsonConvert.SerializeObject(new { isok = isOk.ToString(), curFileName = curDirName });
return Content(json);
}
}
///
/// 下载压缩包
///
/// 文件名
///
public ActionResult DownePackZip(string curFileName)
{
try
{
curFileName = curFileName + ".zip";
var DownPicpath = System.Web.HttpContext.Current.Server.MapPath("/DownPicPackge");
var flag = ImageUtil.DownePackZip(DownPicpath + "/" + curFileName, curFileName);
////flag返回包之后就可以删除包，因为包的已经转为流返回给客户端，无需读取源文件
if (flag && Directory.Exists(DownPicpath))
System.IO.File.Delete(DownPicpath + "/" + curFileName);
return Content(flag.ToString());
}
catch (Exception ex)
{
return Content(ex.Message);
}
}
}
}
c#服务端图片打包下载
标签：for json app current result delete serial max-age invoke
原文地址：https://www.cnblogs.com/May-day/p/11776036.html
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