private void UpdateWords(PDFInfoModel pdfInfo, FileStream outputFile)
{
if (pdfInfo.Word != String.Empty)
{
if (pdfInfo.Slash == '/')
{
pdfInfo.LastKeyword = pdfInfo.Slash + pdfInfo.Word;
}
else if (pdfInfo.Word == "stream")
{
//Not needed for now but possibly for expanding features
pdfInfo.InsideStream = true;
}
else if (pdfInfo.Word == "endstream")
{
pdfInfo.InsideStream = false;
}
if (outputFile != null)
{
//pdfInfo.LastKeyWord?
if (pdfInfo.Slash == '/' && _badKeywords.Contains(pdfInfo.Slash + pdfInfo.Word))
{
string wordExactSwapped = Utilities.SwapName(pdfInfo.WordExact);
outputFile.Write(Utilities.StringToBytes(wordExactSwapped));
Console.WriteLine($"Found a risky keyword. Swapped the casing. See? {wordExactSwapped}");
}
else
{
var outWord = String.Empty;
pdfInfo.WordExact.ForEach(o => outWord.Append(o));
outputFile.Write(Utilities.StringToBytes(outWord));
}
}
}
pdfInfo.Word = String.Empty;
pdfInfo.WordExact = new List <char>();
pdfInfo.HexCode = false;
}
public string SanitizePdf(string fileUrl)
{
//Setup
PDFInfoModel pdfInfo = new PDFInfoModel
{
HexCode = false,
Word = String.Empty,
WordExact = new List <char>(),
LastKeyword = String.Empty,
Slash = Char.MinValue,
};
Guid fileId = Guid.NewGuid();
byte?digit1 = null;
byte?digit2 = null;
string _outputFilePath = $"{_convertedFileDirectory}/{fileId}.disarmed.pdf";
//Get source file
var rawFileManager = new FileManager(fileUrl, fileId, _rawFileDirectory);
try
{
//Create destination file
System.IO.File.Create(_outputFilePath);
using (var outputFile = System.IO.File.OpenWrite(_outputFilePath))
{
//Read and disarm
byte?currentByte = rawFileManager.GetByte();
while (currentByte != null)
{
string currentString = Utilities.ByteToString((byte)currentByte);
char currentChar = currentString[0];
char currentCharUpper = currentString.ToUpper()[0];
if ((currentCharUpper >= 'A' && currentCharUpper <= 'Z') ||
(currentCharUpper >= '0' && currentCharUpper <= '9'))
{
pdfInfo.Word += currentString[0];
pdfInfo.WordExact.Add(currentString[0]);
}
else if (pdfInfo.Slash == '/' && currentChar == '#')
{
//Checking for hexcode
digit1 = rawFileManager.GetByte();
digit2 = digit1 != null?rawFileManager.GetByte() : null;
if (digit2 != null)
{
string digit1String = Utilities.ByteToString((byte)digit1);
string digit2String = Utilities.ByteToString((byte)digit2);
char digit1Char = digit1String.FirstOrDefault();
char digit2Char = digit2String.FirstOrDefault();
char digit1CharUpper = digit1String.ToUpper().FirstOrDefault();
char digit2CharUpper = digit2String.ToUpper().FirstOrDefault();
if (((digit1Char >= '0' && digit1Char <= '9') ||
(digit1CharUpper >= 'A' && digit1CharUpper <= 'F')) &&
(digit2Char >= '0' && digit2Char <= '9') ||
(digit2CharUpper >= 'A' && digit2CharUpper <= 'F'))
{
pdfInfo.HexCode = true;
string hexString = $"{digit1Char}{digit2Char}";
char hexChar = (char)int.Parse(hexString,
System.Globalization.NumberStyles.HexNumber);
pdfInfo.Word += hexChar;
pdfInfo.WordExact.Add(hexChar);
}
else
{
rawFileManager.Unget(digit1);
rawFileManager.Unget(digit2);
UpdateWords(pdfInfo, outputFile);
outputFile.WriteByte((byte)currentByte);
}
}
else
{
rawFileManager.Unget(digit1);
UpdateWords(pdfInfo, outputFile);
if (digit1 != null)
{
outputFile.WriteByte((byte)digit1);
}
}
}
else
{
//Add check for when the number of colors is expressed with more than 3 bytes
UpdateWords(pdfInfo, outputFile);
pdfInfo.Slash = currentChar == '/' ? '/' : Char.MinValue;
outputFile.WriteByte((byte)currentByte);
}
currentByte = rawFileManager.GetByte();
}
UpdateWords(pdfInfo, outputFile);
}
}
catch (Exception e)
{
Console.WriteLine($"Something went wrong while sanitizing the pdf. " +
$" Exception Message: {e.Message} " +
$" StackTrace: {e.StackTrace} ");
}
finally
{
rawFileManager.DeleteFile();
}
return(_outputFilePath);
}
