How to return PDF using iText - c#

I am trying to return a PDF with simple text, but getting the following error when downloading the document: Failed to load PDF document. Any ideas on how to resolve this is appreciated.
MemoryStream ms = new MemoryStream();
PdfWriter writer = new PdfWriter(ms);
PdfDocument pdfDocument = new PdfDocument(writer);
Document document = new Document(pdfDocument);
document.Add(new Paragraph("Hello World"));
//document.Close();
//writer.Close();
ms.Position = 0;
string pdfName = $"IP-Report-{DateTime.Now.ToString("yyyyMMddHHmmssfff")}.pdf";
return File(ms, "application/pdf", pdfName);

You have to close the writer without closing the underlying stream, which will flush its internal buffer. As is, the document isn't being written to the memory stream in its entirety. Everything but ms should be in a using, too.
You can verify this is occuring by checking the length of ms in your code vs. the code below.
When the using (PdfWriter writer =...) closes, it will close the writer, which causes it to flush its pending writes to the underlying stream ms.
MemoryStream ms = new MemoryStream();
using (PdfWriter writer = new PdfWriter(ms))
using (PdfDocument pdfDocument = new PdfDocument(writer))
using (Document document = new Document(pdfDocument))
{
/*
* Depending on iTextSharp version, you might instead use:
* writer.SetCloseStream(false);
*/
writer.CloseStream = false;
document.Add(new Paragraph("Hello World"));
}
ms.Position = 0;
string pdfName = $"IP-Report-{DateTime.Now.ToString("yyyyMMddHHmmssfff")}.pdf";
return File(ms, "application/pdf", pdfName);

Related

iText 7 Asp.Net can't open Pdf (broken)

I am trying to create a PDF using iText 7 in my Asp.Net application. Unfortunately whenever I try to open the PDF it tells me that the file is broken and can't be opened. I have no idea why because my code seems fine to me.
This is what I have:
public ActionResult CreateLieferschein()
{
MemoryStream stream = new MemoryStream();
PdfWriter writer = new PdfWriter(stream);
var pdf = new PdfDocument(writer);
var document = new Document(pdf);
document.Add(new Paragraph("Hello World!"));
return File(stream, "application/pdf", "test.pdf");
}
It looks like you're missing the call to document.Close()
Here's the example from their docs, see the last line:
var writer = new PdfWriter(dest);
var pdf = new PdfDocument(writer);
var document = new Document(pdf);
document.Add(new Paragraph("Hello World!"));
document.Close();

MemoryStream PDF file in ASP.NET Core 2

Keep getting an error 'Cannot access a closed Stream.'
Does the file need to be physically saved on a server first, prior to being Streamed? I am doing the same with Excel file and it works just fine. Trying to use the same principle here with PDF file.
[HttpGet("ExportPdf/{StockId}")]
public IActionResult ExportPdf(int StockId)
{
string fileName = "test.pdf";
MemoryStream memoryStream = new MemoryStream();
// Create PDF document
Document document = new Document(PageSize.A4, 25, 25, 25, 25);
PdfWriter pdfWriter = PdfWriter.GetInstance(document, memoryStream);
document.Open();
document.Add(new Paragraph("Hello World"));
document.Close();
memoryStream.Position = 0;
return File(memoryStream, "application/pdf", fileName);
}
Are you using iText7? If yes, please add that tag onto your question.
using (var output = new MemoryStream())
{
using (var pdfWriter = new PdfWriter(output))
{
// You need to set this to false to prevent the stream
// from being closed.
pdfWriter.SetCloseStream(false);
using (var pdfDocument = new PdfDocument(pdfWriter))
{
...
}
var renderedBuffer = new byte[output.Position];
output.Position = 0;
output.Read(renderedBuffer, 0, renderedBuffer.Length);
...
}
}
Switched to iText& (7.1.1) version as per David Liang comment
Here is the code that worked for me, a complete method:
[HttpGet]
public IActionResult Pdf()
{
MemoryStream memoryStream = new MemoryStream();
PdfWriter pdfWriter = new PdfWriter(memoryStream);
PdfDocument pdfDocument = new PdfDocument(pdfWriter);
Document document = new Document(pdfDocument);
document.Add(new Paragraph("Welcome"));
document.Close();
byte[] file = memoryStream.ToArray();
MemoryStream ms = new MemoryStream();
ms.Write(file, 0, file.Length);
ms.Position = 0;
return File(fileStream: ms, contentType: "application/pdf", fileDownloadName: "test_file_name" + ".pdf");
}

Using itextsharp to merge pdf files within a folder

I'm trying to use codes below to merge the pdf files in a folder and output into a new file but apparently the generated file seems corrupted.
public Boolean MergeForm(String destinationFile, String sourceFolder)
{
try
{
using (MemoryStream stream = new MemoryStream())
using (Document doc = new Document())
using (PdfCopy pdf = new PdfCopy(doc, stream))
{
doc.Open();
PdfReader reader = null;
PdfImportedPage page = null;
foreach (var file in Directory.GetFiles(sourceFolder))
{
reader = new PdfReader(file);
for (int i = 0; i < reader.NumberOfPages; i++)
{
page = pdf.GetImportedPage(reader, i + 1);
pdf.AddPage(page);
}
pdf.FreeReader(reader);
reader.Close();
}
using (FileStream streamX = new FileStream(destinationFile, FileMode.Create))
{
stream.WriteTo(streamX);
}
}
return true;
}
catch (Exception)
{
return false;
}
}
Can anyone spot on where's the problem? Thank you.
Can anyone spot on where's the problem?
Your main problem is that you use the contents of the MemoryStream before the Document and PdfCopy have finished creating the PDF (during the Dispose at the end of the using block). Thus, you save an incomplete PDF file as a result.
Doing it like this instead should work:
using (MemoryStream stream = new MemoryStream())
{
using (Document doc = new Document())
{
PdfCopy pdf = new PdfCopy(doc, stream);
pdf.CloseStream = false;
doc.Open();
PdfReader reader = null;
PdfImportedPage page = null;
foreach (var file in Directory.GetFiles(sourceFolder))
{
reader = new PdfReader(file);
for (int i = 0; i < reader.NumberOfPages; i++)
{
page = pdf.GetImportedPage(reader, i + 1);
pdf.AddPage(page);
}
pdf.FreeReader(reader);
reader.Close();
}
}
using (FileStream streamX = new FileStream(destinationFile, FileMode.Create))
{
stream.WriteTo(streamX);
}
}
BTW, you also see here that I did not put PdfCopy into a using block. This is because the Document implicitly closes the PDFCopy when it is disposed. First disposing the PdfCopy and then the Document (which tries to close the PdfCopy again), therefore, is not necessary and can result in hiding exceptions thrown from within the block by other exceptions occurring in this closing circus.
Furthermore I needed to add the pdf.CloseStream = false, otherwise the memory stream would have been closed when the PdfCopy is closed.
That been said,
Of course you should also use AddDocument instead of iterating over the document pages yourself as already explained by #Bruno.
Your memory footprint would decrease if you immediately wrote to the file stream instead of the memory stream.

Convert html to pdf and merge it with existing pdfs

I have a System.Net.Mail.MailMessage which shall have it's html body and pdf attachments converted into one single pdf.
Converting the html body to pdf works for me with this answer
Converting the pdf attachments into one pdf works for me with this answer
However after ~10 hours of trying I can not come up with a combined solution which does both. All I'm getting are NullReferenceExceptions somewhere in IText source, "the document is not open", etc...
For example, this will throw no error but the resulting pdf will only contain the attachments but not the html email body:
Document document = new Document();
StringReader sr = new StringReader(mail.Body);
HTMLWorker htmlparser = new HTMLWorker(document);
using (FileStream fs = new FileStream(targetPath, FileMode.Create))
{
PdfCopy writer = new PdfCopy(document, fs);
document.Open();
htmlparser.Parse(sr);
foreach (string fileName in pdfList)
{
PdfReader reader = new PdfReader(fileName);
reader.ConsolidateNamedDestinations();
for (int i = 1; i <= reader.NumberOfPages; i++)
{
PdfImportedPage page = writer.GetImportedPage(reader, i);
writer.AddPage(page);
}
PRAcroForm form = reader.AcroForm;
if (form != null)
{
writer.CopyAcroForm(reader);
}
reader.Close();
}
writer.Close();
document.Close();
}
I'm using the LGPL licensed ITextSharp 4.1.6
From v4.1.6 fanboy to v4.1.6 fanboy :D
Looks like the HTMLWorker is closing the documents stream right after parsing. So as a workaround, you could create a pdf from your mailbody in memory. And then add this one together with the attachment to your final pdf.
Here is some code, that should do the trick:
StringReader htmlStringReader = new StringReader("<html><body>Hello World!!!!!!</body></html>");
byte[] htmlResult;
using (MemoryStream htmlStream = new MemoryStream())
{
Document htmlDoc = new Document();
PdfWriter htmlWriter = PdfWriter.GetInstance(htmlDoc, htmlStream);
htmlDoc.Open();
HTMLWorker htmlWorker = new HTMLWorker(htmlDoc);
htmlWorker.Parse(htmlStringReader);
htmlDoc.Close();
htmlResult = htmlStream.ToArray();
}
byte[] pdfResult;
using (MemoryStream pdfStream = new MemoryStream())
{
Document doc = new Document();
PdfCopy copyWriter = new PdfCopy(doc, pdfStream);
doc.Open();
PdfReader htmlPdfReader = new PdfReader(htmlResult);
AppendPdf(copyWriter, htmlPdfReader); // your foreach pdf code here
htmlPdfReader.Close();
PdfReader attachmentReader = new PdfReader("C:\\temp\\test.pdf");
AppendPdf(copyWriter, attachmentReader);
attachmentReader.Close();
doc.Close();
pdfResult = pdfStream.ToArray();
}
using (FileStream fs = new FileStream("C:\\temp\\test2.pdf", FileMode.Create, FileAccess.Write))
{
fs.Write(pdfResult, 0, pdfResult.Length);
}
private void AppendPdf(PdfCopy writer, PdfReader reader)
{
for (int i = 1; i <= reader.NumberOfPages; i++)
{
PdfImportedPage page = writer.GetImportedPage(reader, i);
writer.AddPage(page);
}
}
Ofc you could directly use a FileStream for the final document instead of a MemoryStream as well.

Merging PDF with ITextSharp takes time

I am using ITextSharp to merge PDFs.
My problem is when I merge huge PDFs, it takes a very long time to do it (many minutes). It appears that it takes all this time on the "document.close()".
Here is my code :
iTextSharp.text.Document doc = new iTextSharp.text.Document();
PdfCopy copy = new PdfCopy(doc, msOutput);
copy.SetMergeFields();
doc.Open();
byte[] byteArray = Convert.FromBase64String("someString");
PdfReader reader = new PdfReader(byteArray);
copy.AddDocument(reader);
doc.Close(); // <== It takes time here !
byte[] form = msOutput.ToArray();
Is there anything I did wrong ?
How can I improve this merging time ?
You are missing some Close() calls - this may help to bring your time down:
byte[] form
using (var msOutput = new MemoryStream())
{
iTextSharp.text.Document doc = new iTextSharp.text.Document();
byte[] byteArray = Convert.FromBase64String("someString");
PdfCopy copy = new PdfCopy(doc, msOutput);
copy.SetMergeFields();
doc.Open();
PdfReader reader = new PdfReader(byteArray);
copy.AddDocument(reader);
reader.Close();
copy.Close();
doc.Close();
form = msOutput.ToArray();
}
You should also be sure you are properly disposing of your stream after use.

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