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Readme.md

C# .NET Core implementation

Amazon Textract samples for .NET Core with C#

Prerequisites

Usage

Usage: dotnet run [--switch]
To run this console app, use the following valid switches one at a time:
                     --detect-text-local
                     --detect-text-s3
                     --pdf-text
                     --forms
                     --forms-redaction
                     --tables
                     --tables-expense
                     --reading-order
                     --nlp-comprehend
                     --nlp-medical
                     --translate
                     --search
      e.g. dotnet run --detect-text-s3

Samples

Argument Description
--detect-text-local Example showing processing a document on local machine.
--detect-text-s3 Example showing processing a document in Amazon S3 bucket.
--pdf-text Example showing PDF document processing.
--forms Example showing form (key/value) processing.
--forms-redaction Example showing redacting information in document.
--tables Example showing table processing.
--tables-expense Example showing validation of table data.
--reading-order Example showing printing document in reading order.
--nlp-comprehend Example showing detecting entities and sentiment.
--nlp-medical Example showing detecting medical entities.
--translate Example showing translation of documents.
--search Example showing document indexing in Elasticsearch.

Example usage and result

dotnet-core sanjeet$ dotnet run --forms
default:: US West (Oregon)
........Key: Phone Number:, Value 555-0100
Key: Full Name:, Value Jane Doe
Key: Home Address:, Value 123 Any Street. Any Town, USA
Key: Mailing Address:, Value same as home address
Get Field by Key:
Key: Phone Number:, Value: 555-0100

The following source document was used by the example above to analyze Form data. This document has a Form and a Table on it:

source document

The following AWS services are used:

  • Amazon Textract (for text extraction and analysis)
  • Amazon Comprehend (for natural language processing)
  • Amazon Comprehend Medical (for natural language processing of medical prescriptions/documents)
  • Amazon Elasticsearch (for full text indexing and search)
  • Amazon S3 (for storing scanned documents/images used by Amazon Textract)
  • Amazon Translate (for translating text from English to other supported languages)

Dependencies

appsettings.json file uses your default AWS profile so that you don't have to set AWS credentials in clear text

{
  "AWS": {
    "Profile": "default",
    "Region": "us-west-2"
  }
}

A quick walkthrough of the .csproj file

dotnet-core.csproj file: required .NET libraries - these libraries will be auto-installed as part of the build process

<ItemGroup>
   <PackageReference Include="AWSSDK.Comprehend" Version="3.3.104.13" />
   <PackageReference Include="AWSSDK.ComprehendMedical" Version="3.3.100.31" />
   <PackageReference Include="AWSSDK.Extensions.NETCore.Setup" Version="3.3.100.1" />
   <PackageReference Include="AWSSDK.S3" Version="3.3.102.12" />
   <PackageReference Include="AWSSDK.Textract" Version="3.3.101.23" />
   <PackageReference Include="AWSSDK.Translate" Version="3.3.100.28" />
   <PackageReference Include="Microsoft.Extensions.Configuration" Version="2.2.0" />
   <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="2.2.4" />
   <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.2.0" />
   <PackageReference Include="NEST" Version="6.8.0" />
   <PackageReference Include="System.Drawing.Common" Version="4.5.1" />
</ItemGroup>

The code sample that performs redaction on a form uses Dotnet Core System.Drawing.Commons package. You can add System.Drawing.Common package to the project by using the following dotnet CLI command

dotnet add package System.Drawing.Common --version 4.5.1

NEST is the official Elasticsearch client that's used by this sample to send text for indexing in an Amazon Elasticsearch domain provisioned in AWS. Use the following command to install NEST

dotnet add package NEST --version 6.8.0

AWSSDK.* packages are Nuget client libraries, and can be installed using a command similar to the following

dotnet add package AWSSDK.<package-name>

dotnet-core.csproj file: "test-files" folder has all the required files e.g. pdf, jpg, and png used for testing and they are all copied to the output directory

<ItemGroup>
   <None Update="appsettings.json">
   <CopyToOutputDirectory>Always</CopyToOutputDirectory>
   </None>
</ItemGroup>

<ItemGroup>
   <None Update="test-files\*">
   <CopyToOutputDirectory>Always</CopyToOutputDirectory>
   </None>
</ItemGroup>

To recursively copy files from local disk to S3 use the following command

aws s3 cp dotnet-core/test-files s3://<Your-S3-bucket>/ --include "*" --recursive

Pro tips

If you ever encounter the following error while running this .NET core application in MacOS

Unhandled Exception: System.TypeInitializationException: The type initializer for 'Gdip' threw an exception. ---> System.DllNotFoundException: Unable to load DLL 'libgdiplus': The specified module could not be found.
   at System.Runtime.InteropServices.FunctionWrapper`1.get_Delegate()
   at System.Drawing.SafeNativeMethods.Gdip.GdiplusStartup(IntPtr& token, StartupInput& input, StartupOutput& output)
   at System.Drawing.SafeNativeMethods.Gdip..cctor()
   --- End of inner exception stack trace ---

Install this package

brew install mono-libgdiplus

and if you see the following error

Unhandled Exception: System.ArgumentException: Parameter is not valid.
   at System.Drawing.Graphics.DrawRectangle(Pen pen, Int32 x, Int32 y, Int32 width, Int32 height)

ensure that the following is commented out (grpahics routine is disposed even before it gets an opportunity to DrawRectangle that's why you get the error)

// graphics.Dispose();
// image.Dispose();