[英]DotNetZip creates 0kb files when passing in memory stream
我有一個 Razor 頁面,我想生成一個包含多個 CSV 文件的 Zip 文件。
當我只想生成一個文件時它工作正常,例如
public async Task<FileStreamResult> OnGet(int id)
{
var bankDetails = _paymentFileGenerator.GeneratePaymentFiles(id);
await using var memoryStream = new MemoryStream();
await using var streamWriter = new StreamWriter(memoryStream);
await using var csvWriter = new CsvWriter(streamWriter, CultureInfo.InvariantCulture)
{
Configuration = { HasHeaderRecord = false, }
};
csvWriter.WriteRecords(bankDetails);
streamWriter.Flush();
return new FileStreamResult(new MemoryStream(memoryStream.ToArray()), new MediaTypeHeaderValue("text/csv"))
{
FileDownloadName = "bacs.csv"
};
}
但是當我嘗試將兩個文件的內存流傳遞到 DotNetZip 流時,zip 會下載到瀏覽器,但兩個文件都是 0kb。 關於為什么的任何想法?
public async Task<FileStreamResult> OnGet(int id)
{
var bankFiles = _paymentFileGenerator.GeneratePaymentFiles(id);
using var zipStream = new MemoryStream();
using var zip = new ZipFile();
await using var bankFileStream = new MemoryStream();
await using var bankFileStreamWriter = new StreamWriter(bankFileStream);
await using var bankFileCsvWriter = new CsvWriter(bankFileStreamWriter, CultureInfo.InvariantCulture)
{
Configuration = { HasHeaderRecord = false, }
};
bankFileCsvWriter.WriteRecords(bankFiles.BankFile);
bankFileCsvWriter.Flush();
bankFileStream.Seek(0, SeekOrigin.Begin);
zip.AddEntry("bacs.csv", (name, stream) => bankFileStream.ToArray());
await using var internalFileStream = new MemoryStream();
await using var internalFileStreamWriter = new StreamWriter(internalFileStream);
await using var internalFileCsvWriter = new CsvWriter(internalFileStreamWriter, CultureInfo.InvariantCulture);
internalFileCsvWriter.WriteRecords(bankFiles.InternalFile);
internalFileCsvWriter.Flush();
internalFileStream.Seek(0, SeekOrigin.Begin);
zip.AddEntry("internal.csv", (name, stream) => internalFileStream.ToArray());
zip.Save(zipStream);
zipStream.Seek(0, SeekOrigin.Begin);
return new FileStreamResult(new MemoryStream(zipStream.ToArray()), new MediaTypeHeaderValue("application/zip"))
{
FileDownloadName = "paymentbatch.zip"
};
}
我看過其他 StackOverflow 帖子,其中人們建議添加 Seek() 函數來重置流的位置,但無論是否存在,它對我都不起作用。
調試時,當我調用 zip.AddEntry() 時,我可以看到“bankfileStream”流中有字節,但是當我調用 zip.Save(zipStream) 時,zipStream 顯示 0 字節。
任何建議表示贊賞!
我嘗試了許多不同的選項,但在使用SharpZipLib庫之前沒有任何效果。 這是完整的解決方案:
public async Task<FileStreamResult> OnGet(int id)
{
var bankFiles = _paymentFileGenerator.GeneratePaymentFiles(id);
var bankFileBytes = await GetCsvFileBytes(bankFiles.BankFile, includeHeader: false);
var internalFileBytes = await GetCsvFileBytes(bankFiles.InternalFile);
var files = new List<AttachedFile>
{
new AttachedFile("bacs.csv", bankFileBytes),
new AttachedFile("internal.csv", internalFileBytes)
};
var zipStream = AddFilesToZip(files);
return new FileStreamResult(zipStream, new MediaTypeHeaderValue("application/zip"))
{
FileDownloadName = "paymentbatch.zip"
};
}
public MemoryStream AddFilesToZip(List<AttachedFile> attachedFiles)
{
var outputMemStream = new MemoryStream();
using (var zipStream = new ZipOutputStream(outputMemStream))
{
// 0-9, 9 being the highest level of compression
zipStream.SetLevel(3);
foreach (var file in attachedFiles)
{
var newEntry = new ZipEntry(file.Name) {DateTime = DateTime.Now};
zipStream.PutNextEntry(newEntry);
StreamUtils.Copy(new MemoryStream(file.Bytes), zipStream, new byte[4096]);
}
zipStream.CloseEntry();
// Stop ZipStream.Dispose() from also Closing the underlying stream.
zipStream.IsStreamOwner = false;
}
outputMemStream.Position = 0;
return outputMemStream;
}
private static async Task<byte[]> GetCsvFileBytes<T>(List<T> records, bool includeHeader = true) where T : class
{
await using var bankFileStream = new MemoryStream();
await using var bankFileStreamWriter = new StreamWriter(bankFileStream);
await using var bankFileCsvWriter = new CsvWriter(bankFileStreamWriter, CultureInfo.InvariantCulture)
{
Configuration = {HasHeaderRecord = includeHeader}
};
bankFileCsvWriter.WriteRecords(records);
bankFileStreamWriter.Flush();
return bankFileStream.ToArray();
}
public class AttachedFile
{
public byte[] Bytes { get; set; }
public string Name { get; set; }
public AttachedFile(string name, byte[] bytes)
{
Bytes = bytes;
Name = name;
}
}
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