I have a c# class that takes an HTML and converts it to PDF using wkhtmltopdf.
As you will see below, I am generating 3 PDFs - Landscape, Portrait, and combined of the two.
The properties object contains the html as a string, and the argument for landscape/portrait.
System.IO.MemoryStream PDF = new WkHtmlToPdfConverter().GetPdfStream(properties);
System.IO.FileStream file = new System.IO.FileStream("abc_landscape.pdf", System.IO.FileMode.Create);
PDF.Position = 0;
properties.IsHorizontalOrientation = false;
System.IO.MemoryStream PDF_portrait = new WkHtmlToPdfConverter().GetPdfStream(properties);
System.IO.FileStream file_portrait = new System.IO.FileStream("abc_portrait.pdf", System.IO.FileMode.Create);
PDF_portrait.Position = 0;
System.IO.MemoryStream finalStream = new System.IO.MemoryStream();
PDF.CopyTo(finalStream);
PDF_portrait.CopyTo(finalStream);
System.IO.FileStream file_combined = new System.IO.FileStream("abc_combined.pdf", System.IO.FileMode.Create);
try
{
PDF.WriteTo(file);
PDF.Flush();
PDF_portrait.WriteTo(file_portrait);
PDF_portrait.Flush();
finalStream.WriteTo(file_combined);
finalStream.Flush();
}
catch (Exception)
{
throw;
}
finally
{
PDF.Close();
file.Close();
PDF_portrait.Close();
file_portrait.Close();
finalStream.Close();
file_combined.Close();
}
The PDFs "abc_landscape.pdf" and "abc_portrait.pdf" generate correctly, as expected, but the operation fails when I try to combine the two in a third pdf (abc_combined.pdf).
I am using MemoryStream to preform the merge, and at the time of debug, I can see that the finalStream.length is equal to the sum of the previous two PDFs. But when I try to open the PDF, I see the content of just 1 of the two PDFs.
The same can be seen below:
Additionally, when I try to close the "abc_combined.pdf", I am prompted to save it, which does not happen with the other 2 PDFs.
Below are a few things that I have tried out already, to no avail:
Change CopyTo() to WriteTo()
Merge the same PDF (either Landscape or Portrait one) with itself
In case it is required, below is the elaboration of the GetPdfStream() method.
var htmlStream = new MemoryStream();
var writer = new StreamWriter(htmlStream);
writer.Write(htmlString);
writer.Flush();
htmlStream.Position = 0;
return htmlStream;
Process process = Process.Start(psi);
process.EnableRaisingEvents = true;
try
{
process.Start();
process.BeginErrorReadLine();
var inputTask = Task.Run(() =>
{
htmlStream.CopyTo(process.StandardInput.BaseStream);
process.StandardInput.Close();
});
// Copy the output to a memorystream
MemoryStream pdf = new MemoryStream();
var outputTask = Task.Run(() =>
{
process.StandardOutput.BaseStream.CopyTo(pdf);
});
Task.WaitAll(inputTask, outputTask);
process.WaitForExit();
// Reset memorystream read position
pdf.Position = 0;
return pdf;
}
catch (Exception ex)
{
throw ex;
}
finally
{
process.Dispose();
}
Merging pdf in C# or any other language is not straight forward with out using 3rd party library.
I assume your requirement for not using library is that most Free libraries, nuget packages has limitation or/and cost money for commercial use.
I have made research and found you an Open Source library called PdfClown with nuget package, it is also available for Java. It is Free with out limitation (donate if you like). The library has a lot of features. One such you can merge 2 or more documents to one document.
I supply my example that take a folder with multiple pdf files, merged it and save it to same or another folder. It is also possible to use MemoryStream, but I do not find it necessary in this case.
The code is self explaining, the key point here is using SerializationModeEnum.Incremental:
public static void MergePdf(string srcPath, string destFile)
{
var list = Directory.GetFiles(Path.GetFullPath(srcPath));
if (string.IsNullOrWhiteSpace(srcPath) || string.IsNullOrWhiteSpace(destFile) || list.Length <= 1)
return;
var files = list.Select(File.ReadAllBytes).ToList();
using (var dest = new org.pdfclown.files.File(new org.pdfclown.bytes.Buffer(files[0])))
{
var document = dest.Document;
var builder = new org.pdfclown.tools.PageManager(document);
foreach (var file in files.Skip(1))
{
using (var src = new org.pdfclown.files.File(new org.pdfclown.bytes.Buffer(file)))
{ builder.Add(src.Document); }
}
dest.Save(destFile, SerializationModeEnum.Incremental);
}
}
To test it
var srcPath = #"C:\temp\pdf\input";
var destFile = #"c:\temp\pdf\output\merged.pdf";
MergePdf(srcPath, destFile);
Input examples
PDF doc A and PDF doc B
Output example
Links to my research:
https://csharp-source.net/open-source/pdf-libraries
https://sourceforge.net/projects/clown/
https://www.oipapio.com/question-3526089
Disclaimer: A part of this answer is taken from my my personal web site https://itbackyard.com/merge-multiple-pdf-files-to-one-pdf-file-in-c/ with source code to github.
This answer from Stack Overflow (Combine two (or more) PDF's) by Andrew Burns works for me:
using (PdfDocument one = PdfReader.Open("pdf 1.pdf", PdfDocumentOpenMode.Import))
using (PdfDocument two = PdfReader.Open("pdf 2.pdf", PdfDocumentOpenMode.Import))
using (PdfDocument outPdf = new PdfDocument())
{
CopyPages(one, outPdf);
CopyPages(two, outPdf);
outPdf.Save("file1and2.pdf");
}
void CopyPages(PdfDocument from, PdfDocument to)
{
for (int i = 0; i < from.PageCount; i++)
{
to.AddPage(from.Pages[i]);
}
}
That's not quite how PDFs work. PDFs are structured files in a specific format.
You can't just append the bytes of one to the other and expect the result to be a valid document.
You're going to have to use a library that understands the format and can do the operation for you, or developing your own solution.
PDF files aren't just text and images. Behind the scenes there is a strict file format that describes things like PDF version, the objects contained in the file and where to find them.
In order to merge 2 PDFs you'll need to manipulate the streams.
First you'll need to conserve the header from only one of the files. This is pretty easy since it's just the first line.
Then you can write the body of the first page, and then the second.
Now the hard part, and likely the part that will convince you to use a library, is that you have to re-build the xref table. The xref table is a cross reference table that describes the content of the document and more importantly where to find each element. You'd have to calculate the byte offset of the second page, shift all of the elements in it's xref table by that much, and then add it's xref table to the first. You'll also need to ensure you create objects in the xref table for the page break.
Once that's done, you need to re-build the document trailer which tells an application where the various sections of the document are among other things.
See https://resources.infosecinstitute.com/pdf-file-format-basic-structure/
This is not trivial and you'll end up re-writing lots of code that already exists.
Related
I am basically splitting a PDF document into multiple documents containing one page each. After splitting I perform some operations and the merge the documents back to a single PDF. I am using PDFsharp in c# to do this. Now the problem I am facing is that when I split the document and then add them back, the file size increases from 1.96Mbs to 12.2Mbs. Now after thoroughly testing, I have pointed out that the problem lies not in the operations which I performing after splitting but in the actual splitting and merging of PDF documents. The following are my functions which I have created.
public static List<Stream> SplitPdf(Stream PdfDoc)
{
System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
List<Stream> outputStreamList = new List<Stream>();
PdfSharp.Pdf.PdfDocument inputDocument = PdfReader.Open(PdfDoc, PdfDocumentOpenMode.Import);
for (int idx = 0; idx < inputDocument.PageCount; idx++)
{
PdfSharp.Pdf.PdfDocument outputDocument = new PdfSharp.Pdf.PdfDocument();
outputDocument.Version = inputDocument.Version;
outputDocument.Info.Title =
String.Format("Page {0} of {1}", idx + 1, inputDocument.Info.Title);
outputDocument.Info.Creator = inputDocument.Info.Creator;
outputDocument.AddPage(inputDocument.Pages[idx]);
MemoryStream stream = new MemoryStream();
outputDocument.Save(stream);
outputStreamList.Add(stream);
}
return outputStreamList;
}
public static Stream MergePdfs(List<Stream> PdfFiles)
{
System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
PdfSharp.Pdf.PdfDocument outputPDFDocument = new PdfSharp.Pdf.PdfDocument();
foreach (Stream pdfFile in PdfFiles)
{
PdfSharp.Pdf.PdfDocument inputPDFDocument = PdfReader.Open(pdfFile, PdfDocumentOpenMode.Import);
outputPDFDocument.Version = inputPDFDocument.Version;
foreach (PdfSharp.Pdf.PdfPage page in inputPDFDocument.Pages)
{
outputPDFDocument.AddPage(page);
}
}
Stream compiledPdfStream = new MemoryStream();
outputPDFDocument.Save(compiledPdfStream);
return compiledPdfStream;
}
The question which I have is:
Why am I getting this behaviour?
Is there a solution where I can perform split and merge and then get the file of same size? (Can be of any open-source c# library)
Replying to question 1:
When splitting the files, every file will contain all resources required by the pages it contains.
When merging with PDFsharp again, resources will not be merged and the final document may contain duplicated resources (fonts, images), thus leading to larger files.
This is by design.
i have a netcore 3 app to read and split a PDF containing paychecks of some companies which i am working for.
This app ran pretty well since last builds... my the way, the PDF reader started to fail to parse the contents of any PDF.
PDF is built only with Italian words, no special chars. Few tables and a single logo. I'm not able to attach it due to privacy.
public PaycheckSplitter Read()
{
using (var reader = new PdfReader(new MemoryStream(this._stream)))
{
var doc = new PdfDocument(reader);
this.Paycheck = new PaychecksCollection();
for (int i = 1; i <= doc.GetNumberOfPages(); i++)
{
PdfPage page = doc.GetPage(i);
string text = PdfTextExtractor.GetTextFromPage(page, new LocationTextExtractionStrategy());
if (text.Contains(Consts.BpEnd)) break;
// trying to find something by regex... btw text contains only a sequence of \n\n\n\n...
string cf = Consts.CodFiscale.Match(text).Value;
this.Paychecks.Add(new Paycheck(cf), i);
}
doc.Close();
}
return this;
}
Anything i can do?
As far as i can see... the only and best way to have something to read a PDF text for free is iText7...
I'm trying to evaluate various libraries to read PDF files. One of them is iText 7, the 7.0.4 .NET version to be precise. Some files work fine, but there is at least one file i tested it with, where iText simply returns gibberish (most files work just fine).
This is my code:
private void PdfToText(FileInfo pdfFileInfo, FileInfo textFileInfo)
{
var textFile = new StreamWriter(textFileInfo.FullName);
var pdfDocument = new PdfDocument(new PdfReader(pdfFileInfo.FullName));
var strategy = new LocationTextExtractionStrategy();
for (int i = 1; i <= pdfDocument.GetNumberOfPages(); ++i)
{
var page = pdfDocument.GetPage(i);
string text = PdfTextExtractor.GetTextFromPage(page, strategy);
textFile.Write(text);
}
pdfDocument.Close();
textFile.Close();
}
The resulting file starts with this in hex (and goes on like this as well):
Other libraries can extract the text from this file just fine, selecting the text with Foxit Reader and then use copy paste to Notepad++ also gives me readable text.
I'm sorry, but i can't provide the PDF in question, since it contains confidential data.
Any idea how to fix this?
Major part of my job is automation of engineering process, so I have to create simple program, that compares 2 different version of 1 drawn element, by overlapping drawings, in order to review differences. Drawings represent single sheet PDF files.
I'm using .Net Framework and C# 4.5;
iTextSharp library for editing PDF files;
Initially, I'm getting 2 files, read them and create the third one, that contains the result;
var file1 = "file1.pdf";
var file2 = "file2.pdf";
var result = "result.pdf";
using (Stream f1Stream = new FileStream(file1, FileMode.Open))
using (Stream f2Stream = new FileStream(file2, FileMode.Open))
using (Stream resultStream = new FileStream(result, FileMode.Create, FileAccess.ReadWrite))
using (PdfReader f2Reader = new PdfReader(f2Stream))
using (PdfReader f1Reader = new PdfReader(f1Stream))
{
PdfStamper pdfStamper = new PdfStamper(f1Reader, resultStream);
PdfContentByte pdfContentByte = pdfStamper.GetOverContent(1);
var page = pdfStamper.GetImportedPage(f2Reader, 1);
pdfContentByte.AddTemplate(page,2,2);
pdfStamper.Close();
}
The code above makes just that, but a few sequential questions are arising
I want to change the color of elements in the result file i.e. elements that come from the 1st drawing in green and the others from 2nd one - in red color. Maybe I have to change the color of entities in initial 2 PDFs and then to merge;
Initial files have layers, and because they are two sequential revision of the same construction element and differences between them are very few, they have identical layers. And I want to have " layerFoo " and " layerFoo# " in the result PDF. Maybe I have to rename all the layers in one the the 2 initial PDFs and then to merge them.
Аll suggestions are welcomed including usage of another library :)
--> Edit1
Big thanks to Chris Haas! You are absolutely right for token type and string value! iTextRUPS is great helping tool for understanding the structure of PDF files.
Following code is taken from the post that you pointed me out.
The following statement:
stream.SetData(System.Text.Encoding.ASCII.GetBytes(String.Join("\n", newBuf.ToArray())));
updates the stream of the file and then with
using (var fs = new FileStream(file2, FileMode.Create, FileAccess.Write, FileShare.None))
{
var stamper = new PdfStamper(reader, fs);
reader.SetPageContent(1,reader.GetPageContent(1));
stamper.Close();
}
the new file is created with updated stream.
I made 1 simple test file with only 2 lines, change their color and save back to a new file.
No problem!
After that, I tried the same simple operation with real file, that represents real drawing of construction element, the result file was less than half of the original and was broken.
What comes to mind is the updated stream is saved to the new file but the other information inside other containers is not saved, it's just the stream.
Because I stuck with that, I continue to the next step of investigation -> layers
I wrote this code in order to get available layers in a PDF file. I will try to insert more records into layers dictionary to see what will happen.
var resourcesReference = page.Get(PdfName.RESOURCES) as PdfIndirectReference;
var resources = PdfReader.GetPdfObject(resourcesReference) as PdfDictionary;
var propertiesObjhectReferences = resources.Get(PdfName.PROPERTIES);
var properties = PdfReader.GetPdfObject(propertiesObjhectReferences) as PdfDictionary;
foreach (var property in properties.Keys)
{
var layerReference = properties.Get(property);
var layerObject = PdfReader.GetPdfObject(layerReference) as PdfDictionary;
foreach (var key in layerObject.Keys)
{
if (key.ToString()!=PdfName.TYPE.ToString())
{
var layerName = layerObject.GetAsString(key).ToUnicodeString();
}
}
}
If I come back to my main goal from the top of the post, I tends to insert the stream and layers from first file into second in order to obtain result file, that contains objects from the previous 2, painted in different colors + layers from both.
Feel free to suggest me another, more simpler and beautiful solution! I will be happy if you revise my code and correct it! Thank You very much!
EDIT 2
I will simplify the work because the lack of time, just change the color of entities inside one PDF and put it on the background on the other.
const string Pdf = "file1.pdf";
var reader = new PdfReader(Pdf);
var page = reader.GetPageN(1);
var objectReference = page.Get(PdfName.CONTENTS) as PdfIndirectReference;
var stream = (PRStream)PdfReader.GetPdfObject(objectReference);
var streamBytes = PdfReader.GetStreamBytes(stream);
var tokenizer = new PRTokeniser(new RandomAccessFileOrArray(streamBytes));
var newBuf = new List<string>();
while (tokenizer.NextToken())
{
var token = tokenizer.StringValue;
newBuf.Add(token);
if (tokenizer.TokenType == PRTokeniser.TokType.OTHER
&& newBuf[newBuf.Count - 1].Equals("S", StringComparison.CurrentCultureIgnoreCase))
{
newBuf.Insert(newBuf.Count - 1, "0");
newBuf.Insert(newBuf.Count - 1, "1");
newBuf.Insert(newBuf.Count - 1, "1");
newBuf.Insert(newBuf.Count - 1, "RG");
}
}
var resultStream = String.Join("\n", newBuf.ToArray());
stream.SetData(System.Text.Encoding.ASCII.GetBytes(resultStream));
var file2 = Pdf.Insert(Pdf.Length - 4, "Result");
using (var fs = new FileStream(file2, FileMode.Create, FileAccess.Write, FileShare.None))
{
var stamper = new PdfStamper(reader, fs);
reader.SetPageContent(1, reader.GetPageContent(1));
stamper.Close();
}
Result PDF is broken and iTextRUPS throws exception when try to get the stream data from the page.
I have a big number pdf documents with xml files attached to them. I would like to extract those attached xml files and read them. How can I do this programatically using .net?
iTextSharp is also quite capable of extracting attachments... Though you might have to use the low level objects to do so.
There are two ways to embed files in a PDF:
In a File Annotation
At the document level "EmbeddedFiles".
Once you have a file specification dictionary from either source, the file itself will be a stream within the dictionary labeled "EF" (embedded file).
So to list all the files at the document level, one would write code (in Java) as such:
Map<String, byte[]> files = new HashMap<String,byte[]>();
PdfReader reader = new PdfReader(pdfPath);
PdfDictionary root = reader.getCatalog();
PdfDictionary names = root.getAsDict(PdfName.NAMES); // may be null
PdfDictionary embeddedFilesDict = names.getAsDict(PdfName.EMBEDDEDFILES); //may be null
PdfArray embeddedFiles = embeddedFilesDict.getAsArray(PdfName.NAMES); // may be null
int len = embeddedFiles.size();
for (int i = 0; i < len; i += 2) {
PdfString name = embeddedFiles.getAsString(i); // should always be present
PdfDictionary fileSpec = embeddedFiles.getAsDict(i+1); // ditto
PdfDictionary streams = fileSpec.getAsDict(PdfName.EF);
PRStream stream = null;
if (streams.contains(PdfName.UF))
stream = (PRStream)streams.getAsStream(PdfName.UF);
else
stream = (PRStream)streams.getAsStream(PdfName.F); // Default stream for backwards compatibility
if (stream != null) {
files.put( name.toUnicodeString(), PdfReader.getStreamBytes((PRStream)stream));
}
}
This is an old question, nonetheless I think my alternative solution (using PDF Clown) may be of some interest as it's way much cleaner (and more complete, as it iterates both at document and page level) than the code fragments previously proposed:
using org.pdfclown.bytes;
using org.pdfclown.documents;
using org.pdfclown.documents.files;
using org.pdfclown.documents.interaction.annotations;
using org.pdfclown.objects;
using System;
using System.Collections.Generic;
void ExtractAttachments(string pdfPath)
{
Dictionary<string, byte[]> attachments = new Dictionary<string, byte[]>();
using(org.pdfclown.files.File file = new org.pdfclown.files.File(pdfPath))
{
Document document = file.Document;
// 1. Embedded files (document level).
foreach(KeyValuePair<PdfString,FileSpecification> entry in document.Names.EmbeddedFiles)
{EvaluateDataFile(attachments, entry.Value);}
// 2. File attachments (page level).
foreach(Page page in document.Pages)
{
foreach(Annotation annotation in page.Annotations)
{
if(annotation is FileAttachment)
{EvaluateDataFile(attachments, ((FileAttachment)annotation).DataFile);}
}
}
}
}
void EvaluateDataFile(Dictionary<string, byte[]> attachments, FileSpecification dataFile)
{
if(dataFile is FullFileSpecification)
{
EmbeddedFile embeddedFile = ((FullFileSpecification)dataFile).EmbeddedFile;
if(embeddedFile != null)
{attachments[dataFile.Path] = embeddedFile.Data.ToByteArray();}
}
}
Note that you don't have to bother with null pointer exceptions as PDF Clown provides all the necessary abstraction and automation to ensure smooth model traversal.
PDF Clown is an LGPL 3 library, implemented both in Java and .NET platforms (I'm its lead developer): if you want to get it a try, I suggest you to check out its SVN repository on sourceforge.net as it keeps evolving.
Look for ABCpdf-Library, very easy and fast in my opinion.
What I got working is slightly different then anything else I have seen online.
So, just in case, I thought I would post this here to help someone else. I had to go through many different iterations to figure out - the hard way - what I needed to get it to work.
I am merging two PDFs into a third PDF, where one of the first two PDFs may have file attachments that need to be carried over into the third PDF. I am working completely in streams with ASP.NET, C# 4.0, ITextSharp 5.1.2.0.
// Extract Files from Submit PDF
Dictionary<string, byte[]> files = new Dictionary<string, byte[]>();
PdfDictionary names;
PdfDictionary embeddedFiles;
PdfArray fileSpecs;
int eFLength = 0;
names = writeReader.Catalog.GetAsDict(PdfName.NAMES); // may be null, writeReader is the PdfReader for a PDF input stream
if (names != null)
{
embeddedFiles = names.GetAsDict(PdfName.EMBEDDEDFILES); //may be null
if (embeddedFiles != null)
{
fileSpecs = embeddedFiles.GetAsArray(PdfName.NAMES); //may be null
if (fileSpecs != null)
{
eFLength = fileSpecs.Size;
for (int i = 0; i < eFLength; i++)
{
i++; //objects are in pairs and only want odd objects (1,3,5...)
PdfDictionary fileSpec = fileSpecs.GetAsDict(i); // may be null
if (fileSpec != null)
{
PdfDictionary refs = fileSpec.GetAsDict(PdfName.EF);
foreach (PdfName key in refs.Keys)
{
PRStream stream = (PRStream)PdfReader.GetPdfObject(refs.GetAsIndirectObject(key));
if (stream != null)
{
files.Add(fileSpec.GetAsString(key).ToString(), PdfReader.GetStreamBytes(stream));
}
}
}
}
}
}
}
You may try Aspose.Pdf.Kit for .NET. The PdfExtractor class allows you to extract attachments with the help of two methods: ExtractAttachment and GetAttachment. Please see an example of attachment extraction.
Disclosure: I work as developer evangelist at Aspose.