即时创建一堆 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，可能很大(列表中有 500 个 4MB JPG).我希望能够在请求中完成所有操作并立即开始下载，并在构建时创建和流式传输 zip.它不应该驻留在服务器的内存或磁盘中.

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.

我最接近的是这个:注意:urls 是指向文件名的 URL 的键值对，因为它们应该存在于创建的 zip 中

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 中的每个 JPG 文件只是一个文本文件，上面写着System.Net.ConnectStream"我对此还有其他尝试，可以构建一个包含正确文件的 zip 文件，但是您可以通过开始时的延迟判断服务器完全在内存中构建 zip，然后在最后将其炸毁.当文件数接近 50 时，它根本没有响应.评论中的部分给了我同样的结果，我也试过 Ionic.Zip.

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 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

所以回答我自己的问题 - 这里是适合我的解决方案:

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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