RPA Robotic Process Automation – Make Large PDF Document Searchable Using Parallel Processing – C#

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RPA Robotic Process Automation – Make Large PDF Document Searchable Using Parallel Processing – C#

printable version:
ByteScout-Robotic-Process-Automation-C-sharp-C-sharp.pdf

How to make large PDF document searchable using parallel processing in C# with ByteScout Robotic Process Automation

What is ByteScout Robotic Process Automation? It is set of integrated APIs for quick replaccement of manual data processing with robotic process automations.

On-demand (REST Web API) version:
Web API (on-demand version)

On-premise offline SDK for Windows:
60 Day Free Trial (on-premise)

MultithreadProcessing.csproj

      <?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{0B102DA4-C143-481D-A076-1F56E3CB1CF5}</ProjectGuid>
    <OutputType>Exe</OutputType>
    <RootNamespace>MultithreadProcessing</RootNamespace>
    <AssemblyName>MultithreadProcessing</AssemblyName>
    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="Bytescout.PDFExtractor, Version=8.6.0.2917, Culture=neutral, PublicKeyToken=f7dd1bd9d40a50eb, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>C:\Program Files\Bytescout PDF Extractor SDK\net4.00\Bytescout.PDFExtractor.dll</HintPath>
    </Reference>
    <Reference Include="Bytescout.PDFExtractor.OCRExtension, Version=8.6.0.2917, Culture=neutral, PublicKeyToken=f7dd1bd9d40a50eb, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>C:\Program Files\Bytescout PDF Extractor SDK\net4.00\Bytescout.PDFExtractor.OCRExtension.dll</HintPath>
    </Reference>
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Program.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
  </ItemGroup>
  <ItemGroup>
    <Content Include="sample.pdf">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
</Project>

MultithreadProcessing.sln

      
Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio 15
VisualStudioVersion = 15.0.26730.10
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MultithreadProcessing", "MultithreadProcessing.csproj", "{0B102DA4-C143-481D-A076-1F56E3CB1CF5}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|Any CPU = Debug|Any CPU
		Release|Any CPU = Release|Any CPU
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
		{0B102DA4-C143-481D-A076-1F56E3CB1CF5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
		{0B102DA4-C143-481D-A076-1F56E3CB1CF5}.Debug|Any CPU.Build.0 = Debug|Any CPU
		{0B102DA4-C143-481D-A076-1F56E3CB1CF5}.Release|Any CPU.ActiveCfg = Release|Any CPU
		{0B102DA4-C143-481D-A076-1F56E3CB1CF5}.Release|Any CPU.Build.0 = Release|Any CPU
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
		HideSolutionNode = FALSE
	EndGlobalSection
	GlobalSection(ExtensibilityGlobals) = postSolution
		SolutionGuid = {50466307-7059-438B-8545-42FDA71BC1A6}
	EndGlobalSection
EndGlobal

Program.cs

      using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using Bytescout.PDFExtractor;

namespace MultithreadProcessing
{
	class Program
	{
	    // Limit to 4 threads in queue.
	    // Set this value to number of your processor cores for max performance.
	    private static readonly Semaphore ThreadLimiter = new Semaphore(4, 4);

        static void Main(string[] args)
		{
			const string inputFile = "sample.pdf";
			const string resultFile = "result.pdf";

			int pageCount;

			// Get document page count
			using (var infoExtractor = new InfoExtractor("demo", "demo"))
			{
				infoExtractor.LoadDocumentFromFile(inputFile);
				pageCount = infoExtractor.GetPageCount();
			}
			
			// Process the document by 10-page pieces

			int numberOfThreads = pageCount / 10;
			if (pageCount - numberOfThreads * 10 > 0)
				numberOfThreads += 1;

			WaitHandle[] doneEvents = new WaitHandle[numberOfThreads];
			Stopwatch stopwatch = Stopwatch.StartNew();
			int startPage, endPage;
			string[] pieces = new string[numberOfThreads];

			for (int i = 0; i < numberOfThreads; i++)
			{
			    // Wait for the queue
			    ThreadLimiter.WaitOne();

                doneEvents[i] = new ManualResetEvent(false);
				startPage = i * 10;
				endPage = Math.Min(pageCount - 1, (i + 1) * 10 - 1);

				pieces[i] = string.Format("temp-{0}-{1}.pdf", startPage, endPage);
				ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc),
					new object[] { i, doneEvents[i], inputFile, pieces[i], startPage, endPage });
			}

			// Wait for all threads
			WaitHandle.WaitAll(doneEvents);

			// Merge pieces 
			using (DocumentMerger merger = new DocumentMerger("demo", "demo"))
				merger.Merge(pieces, resultFile);

			// Delete temp files
			foreach (string tempFile in pieces)
				File.Delete(tempFile);

			Console.WriteLine("All done in {0}.", stopwatch.Elapsed);
			Console.WriteLine();

			Console.WriteLine("Press any key to exit...");
			Console.ReadKey();
		}

		private static void ThreadProc(object stateInfo)
		{
			int threadIndex = (int) ((object[]) stateInfo)[0];
			ManualResetEvent doneEvent = (ManualResetEvent) ((object[]) stateInfo)[1];
			string inputFile = (string) ((object[]) stateInfo)[2];
			string outputFile = (string)((object[])stateInfo)[3];
			int startPage = (int)((object[])stateInfo)[4];
			int endPage = (int)((object[])stateInfo)[5];

            try
		    {
		        Console.WriteLine("Thread #{0} started with the page range from {1} to {2}.", threadIndex, startPage, endPage);

		        Stopwatch stopwatch = Stopwatch.StartNew();

		        // Extract a piece of document
		        string chunk = string.Format("temp-{0}-{1}", startPage, endPage);
		        using (DocumentSplitter splitter = new DocumentSplitter("demo", "demo"))
		            splitter.ExtractPageRange(inputFile, chunk, startPage + 1, endPage + 1);

		        // Process the piece
		        using (SearchablePDFMaker searchablePdfMaker = new SearchablePDFMaker("demo", "demo"))
		        {
		            searchablePdfMaker.OCRDetectPageRotation = true;
		            searchablePdfMaker.OCRLanguageDataFolder = @"c:\Program Files\Bytescout PDF Extractor SDK\ocrdata_best\";
		            searchablePdfMaker.LoadDocumentFromFile(chunk);

		            // 300 DPI resolution is recommended. 
		            // Using of higher values will slow down the processing but does not guarantee the higher quality.
		            searchablePdfMaker.OCRResolution = 300;

		            searchablePdfMaker.MakePDFSearchable(outputFile);
		        }

		        File.Delete(chunk);

		        Console.WriteLine("Thread #{0} finished in {1}.", threadIndex, stopwatch.Elapsed);
		    }
            finally
            {
                // Signal the thread is finished
                doneEvent.Set();

                // Release semaphore
                ThreadLimiter.Release();
            }
        }
	}
}