通过Resposne发送内存中生成的.PDF文件

Question

So I have problem with Resposne file. I can send some file but it is corrupted. I know my pdf librabry works fine (checked on console app)

    public void Get(ClaimExportRequest exportRequest)
    {
               var str = ExportToPdf(claimDataTable);
            using (var streams = new MemoryStream(str))
            {
                base.Response.AddHeader("Content-Disposition", "attachment; filename=report.pdf");
                base.Response.AddHeader("Content-Length", str.Length.ToString(CultureInfo.InvariantCulture));
                base.Response.ContentType = "application/octet-stream";
                streams.WriteTo(base.Response.OutputStream);
            }
            base.Response.EndRequest(true);
    }


    public byte[] ExportToPdf(DataTable dt)
    {

        var mem = new MemoryStream();
        var doc = new Document(new Rectangle(100f, 300f));
        PdfWriter.GetInstance(doc, mem);
        doc.Open();
        doc.Add(new Paragraph("This is a custom size"));
        return mem.ToArray();
    }

I have another part that creates CSV file and that one is fine!

        using (var streamOfCsvString = 

GenerateStreamFromString(csvBodyFromDt))
            {
                base.Response.UseBufferedStream = true;
                base.Response.AddHeader("Content-Disposition", "attachment; filename=data.csv");
                base.Response.AddHeader("Content-Length", streamOfCsvString.Length.ToString(CultureInfo.InvariantCulture));
                base.Response.ContentType = "text/csv";
                streamOfCsvString.CopyTo(base.Response.OutputStream);
            }
  base.Response.EndRequest(true);

I tried that method too with changed data to pdf.

Any idea what is wrong in first Get? I know some lines are unnesesery but i tried everything that I found

Client

 downloadURL: function(url) {
    var hiddenIFrameID, iframe;
    hiddenIFrameID = 'hiddenDownloader';
    iframe = document.getElementById(hiddenIFrameID);
    if (iframe === null) {
      iframe = document.createElement('iframe');
      iframe.id = hiddenIFrameID;
      iframe.style.display = 'none';
      document.body.appendChild(iframe);
    }
    return iframe.src = url;
  }

EDIT

I made code that creates this same file at harddrive to check

  var doc = new Document(new Rectangle(100f, 300f));
            using (var fileStream = new FileStream("c:\\my.pdf", FileMode.Create))
            {

                PdfWriter.GetInstance(doc, fileStream);
                doc.Open();
                doc.Add(new Paragraph("This is a custom size"));
                base.Response.AddHeader("Content-Disposition", "attachment; filename=report.pdf");
                base.Response.AddHeader("Content-Length",
                    fileStream.Length.ToString(CultureInfo.InvariantCulture));
                base.Response.ContentType = "application/octet-stream";
                fileStream.CopyTo(base.Response.OutputStream); //WriteTo 
                doc.Close();
            }

            base.Response.EndRequest(true);

File is fine but, when doc.Close() is missing then file on the hard drive is corrupted. But on the server side now I get 0 kB files (empty files)

Answer 1

From your example code, simply adding the doc.Close() did the trick for me.

public byte[] ExportToPdf(DataTable dt)
{

    var mem = new MemoryStream();
    var doc = new Document(new Rectangle(100f, 300f));
    PdfWriter.GetInstance(doc, mem);
    doc.Open();
    doc.Add(new Paragraph("This is a custom size"));
    doc.Close();
    return mem.ToArray();
}

Edit: Like I said on my comment, you should enclose the MemoryStream in a using, like this:

public byte[] ExportToPdf(DataTable dt)
{
    using (var mem = new MemoryStream())
    {
        var doc = new Document(new Rectangle(100f, 300f));
        PdfWriter.GetInstance(doc, mem);
        doc.Open();
        doc.Add(new Paragraph("This is a custom size"));
        doc.Close();
        return mem.ToArray();
    }
}

Answer 2

Your code should look like this:

using (var dataStream = ...)
{
    ...
    dataStream.CopyTo(base.Response.OutputStream);  
}
base.Response.EndRequest(true);

The end of the using block will Flush , Close and then Dispose the dataStream . The call to Flush will make sure any data still sitting in a buffer will be copied over, instead of waiting for potentially more data. EndRequest should be called only after the data has been fully written to the OutputStream , so it should be called after the using block that will Flush the dataStream .