动态创建一堆URL的动态zip [英] Creating a dynamic zip of a bunch of URLs on the fly

问题描述

我正在尝试动态创建任何大小的zip文件。 zip存档的来源是一堆URL，并且可能很大（列表中有500个4MB JPG）。我希望能够处理请求中的所有内容，并立即开始下载，并在构建时创建并传输zip。它应该不必驻留在内存或服务器上的磁盘上。

I am trying to create a zip file of any size on the fly. The source of the zip archive is a bunch of URLs and could be potentially large (500 4MB JPGs in the list). I want to be able to do everything inside the request and have the download start right away and have the zip created and streamed as it is built. It should not have to reside in memory or on disk on the server.

我最接近的是：
注意：urls是URL的键值对

The closest I have come is this: Note: urls is a keyvaluepair of URLs to the file names as they should exist in the created zip

Response.ClearContent();
Response.ClearHeaders();
Response.ContentType = "application/zip";
Response.AddHeader("Content-Disposition", "attachment; filename=DyanmicZipFile.zip");

using (var memoryStream = new MemoryStream())
{
    using (var archive = new ZipArchive(memoryStream, ZipArchiveMode.Create, true))
    {
        foreach (KeyValuePair<string, string> fileNamePair in urls)
        {
            var zipEntry = archive.CreateEntry(fileNamePair.Key);

            using (var entryStream = zipEntry.Open())
                using (WebClient wc = new WebClient())
                    wc.OpenRead(GetUrlForEntryName(fileNamePair.Key)).CopyTo(entryStream);

                //this doesn't work either
                //using (var streamWriter = new StreamWriter(entryStream))
                //  using (WebClient wc = new WebClient())
                //      streamWriter.Write(wc.OpenRead(GetUrlForEntryName(fileNamePair.Key)));
        }
    }

    memoryStream.WriteTo(Response.OutputStream);
}
HttpContext.Current.ApplicationInstance.CompleteRequest();

此代码为我提供了一个zip文件，但是zip文件中的每个JPG文件只是一个文本文件，说 System.Net.ConnectStream，对此我还有其他尝试，它们确实在内部包含适当的文件的情况下构建了一个zip文件，但是您可以通过延迟一开始就知道服务器已在内存中完全构建了zip，然后对其进行了爆炸最后。当文件数接近50时，它根本不响应。注释中的部分也给了我尝试过Ionic.Zip的相同结果。

This code gives me a zip file, but each JPG file inside the zip is just a text file that says "System.Net.ConnectStream" I have other attempts on this that do build a zip file with the proper files inside, but you can tell by the delay at the beginning that the server is completely building the zip in memory and then blasting it down at the end. It doesn't respond at all when the file count gets near 50. The part in comments gives me the same result I have tried Ionic.Zip as well.

这是IIS8上的.NET 4.5。我正在使用VS2013进行构建，并尝试在AWS Elastic Beanstalk上运行它。

This is .NET 4.5 on IIS8. I am building with VS2013 and trying to run this on AWS Elastic Beanstalk.

推荐答案

所以要回答我自己的问题-这是适用于我的解决方案：

So to answer my own question - here is the solution that works for me:

private void ProcessWithSharpZipLib()
{
    byte[] buffer = new byte[4096];

    ICSharpCode.SharpZipLib.Zip.ZipOutputStream zipOutputStream = new ICSharpCode.SharpZipLib.Zip.ZipOutputStream(Response.OutputStream);
    zipOutputStream.SetLevel(0); //0-9, 9 being the highest level of compression
    zipOutputStream.UseZip64 = ICSharpCode.SharpZipLib.Zip.UseZip64.Off;

    foreach (KeyValuePair<string, string> fileNamePair in urls)
    {
        using (WebClient wc = new WebClient())
        {
            using (Stream wcStream = wc.OpenRead(GetUrlForEntryName(fileNamePair.Key)))
            {
                ICSharpCode.SharpZipLib.Zip.ZipEntry entry = new ICSharpCode.SharpZipLib.Zip.ZipEntry(ICSharpCode.SharpZipLib.Zip.ZipEntry.CleanName(fileNamePair.Key));

                zipOutputStream.PutNextEntry(entry);

                int count = wcStream.Read(buffer, 0, buffer.Length);
                while (count > 0)
                {
                    zipOutputStream.Write(buffer, 0, count);
                    count = wcStream.Read(buffer, 0, buffer.Length);
                    if (!Response.IsClientConnected)
                    {
                        break;
                    }
                    Response.Flush();
                }
            }
        }
    }
    zipOutputStream.Close();

    Response.Flush();
    Response.End();
}

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