public async Task <ScanResult> ScanAsync(string filename)
{
FileInfo fileInfo = new FileInfo(filename);
LoggingSection log = logging.CreateChild(fileInfo.Name);
log.Verbose($"Starting {GetType().Name} on {fileInfo.FullName}");
DateTime timeStarted = DateTime.Now;
string result = null;
bool succeeded;
Exception exception = null;
try
{
result = await DoScanAsync(fileInfo.FullName, log);
succeeded = true;
log.Verbose("Scan was successfull");
}
catch (Exception e)
{
succeeded = false;
exception = e;
log.Warning($"Scan failed: {e.Message}{Environment.NewLine}{e.StackTrace}");
}
DateTime timeEnded = DateTime.Now;
log.Dispose();
return(new ScanResult(result, fileInfo.FullName, this, timeStarted, timeEnded, succeeded, exception));
}
public void Log_ReturnedLogMessage_ShouldHaveLogLevelVerbose()
{
//Arrange
LoggingSection loggingSection = new LoggingSection(this);
LogMessage logMessage;
//Act
logMessage = loggingSection.Verbose("Test");
//Assert
Assert.NotNull(logMessage);
Assert.Equal(LogLevel.VERBOSE, logMessage.LogLevel);
}
/// <summary>
/// Constructs a FileLogHandler
/// </summary>
/// <param name="path">Path to the file that should be written into</param>
/// <param name="format">Pattern according to which a LogMessage is converted into a string. If not provided, a default pattern will be used.</param>
/// <param name="enabledLogLevels">Enabled LogLevels. If not provided, all LogLevels are enabled by default.</param>
public FileLogHandler(string path, string format = null, LogLevel[] enabledLogLevels = null) : base(format, null, enabledLogLevels)
{
using LoggingSection log = new LoggingSection(this);
DirectoryInfo parent = Directory.GetParent(path);
if (!parent.Exists)
{
log.Verbose($"Creating directory {parent.FullName}.");
parent.Create();
}
try
{
streamWriter = new StreamWriter(File.Open(path, FileMode.OpenOrCreate, FileAccess.Write), Encoding.UTF8);
streamWriter.AutoFlush = true;
}
catch (Exception e)
{
streamWriter = null;
log.Error($"Failed to open FileStream on {path}: {e.Message}.");
}
}
protected override string DoScan(string filename, LoggingSection log)
{
PdfDocument pdfDocument = PdfReader.Open(filename);
StringBuilder stringBuilder = new StringBuilder();
for (int pageIndex = 0; pageIndex < pdfDocument.PageCount; pageIndex++)
{
log.Verbose($"Scanning page {pageIndex + 1} of {pdfDocument.PageCount}");
PdfPage pdfPage = pdfDocument.Pages[pageIndex];
//Extract text from text elements
stringBuilder.Append($"{ExtractTextFromPdfPage(pdfPage)}{Environment.NewLine}");
//Extract text from image elements with Tesseract OCR - awesome! :)
PdfDictionary resources = pdfPage.Elements.GetDictionary("/Resources");
if (resources != null)
{
PdfDictionary xObjects = resources.Elements.GetDictionary("/XObject");
if (xObjects != null)
{
ICollection <PdfItem> items = xObjects.Elements.Values;
foreach (PdfItem item in items)
{
PdfReference reference = item as PdfReference;
if (reference != null)
{
PdfDictionary xObject = reference.Value as PdfDictionary;
if (xObject != null && xObject.Elements.GetString("/Subtype") == "/Image")
{
Bitmap bitmap = PdfImageToBitmap(xObject);
if (bitmap == null)
{
log.Error("Could not extract bitmap from PDF image element. Seems like the PDF image filter type is not supported. Skipping element!");
continue;
}
log.Debug("Rotating image");
bitmap.RotateFlip(RotateFlipType.Rotate90FlipNone);
log.Debug("Upscaling image 2x");
BitmapUtils.Scale(ref bitmap, 2);
log.Debug("Grayscaling image");
BitmapUtils.GrayscaleWithLockBits(bitmap);
log.Debug("Denoising image");
BitmapUtils.DenoiseWithLockBits(bitmap);
log.Debug("Applying OCR on image");
Pix pix = PixConverter.ToPix(bitmap);
TesseractEngine tesseractEngine = Services.OCRProvider.AwaitResource();
Page tesseractPage = tesseractEngine.Process(pix);
try
{
string text = tesseractPage.GetText();
log.Debug($"Text is {text.Length} characters long");
if (!string.IsNullOrWhiteSpace(text) && text != "\n")
{
stringBuilder.Append(text.Replace("\n", " "));
}
}
catch (InvalidOperationException e)
{
log.Error($"OCR failed on Page {pageIndex} of file {filename}:\n{e.StackTrace}");
}
Services.OCRProvider.Feed(tesseractEngine);
pix.Dispose();
}
}
}
}
}
stringBuilder.Append("\n");
}
log.Debug("Trimming text");
string documentText = stringBuilder.ToString();
documentText = documentText.Trim();
while (documentText.Contains(" "))
{
documentText = documentText.Replace(" ", " ");
}
while (documentText.Contains("\n\n"))
{
documentText = documentText.Replace("\n\n", "\n");
}
return(stringBuilder.ToString());
}