Using ClamAV with .Net Core

Introduction:
In this article, we'll explore how to scan files for viruses using the ClamAV REST API in a .NET Core application. We'll leverage Docker to run the ClamAV service and utilize the System.Net.Http.HttpClient library for making HTTP requests.

Prerequisites:
Before getting started, ensure the following requirements are met:

Dotnet Core is installed on your machine.
Docker Desktop or Docker Engine is installed and running.
Pull the ClamAV REST API Docker image by following the instructions in the clamav-rest GitHub repository.

FileModel Class:
To represent the file we want to scan, we'll create a FileModel class with the following properties:

public class FileModel
 {
     public string FileName { get; set; }
     public byte[] FileBytes { get; set; }
     public string FileContentType { get; set; }
 }

1. Sending the File for Scanning: To send a file for scanning, follow these steps:

Get the file you want to scan as a byte array. You can use the File.ReadAllBytes method to read the file contents.

FileModel fileModel = new FileModel
{
    FileName = "example.txt",
    FileBytes = File.ReadAllBytes("path/to/file"),
    FileContentType = "text/plain"
};

1. Create a ByteArrayContent using the file bytes:

var contentByte = new ByteArrayContent(fileModel.FileBytes);

1. Create a MultipartFormDataContent and add the ByteArrayContent to it:

var multiContent = new MultipartFormDataContent
{
    { contentByte, "file", fileModel.FileName }
};

Sending the Request:
Once we have the file prepared, we can send a request to the ClamAV scanner using the HttpClient class:

using (var httpClient = new HttpClient())
{
    using (var content = new MultipartFormDataContent())
    {
        var fileContent = new ByteArrayContent(fileModel.FileBytes);
        content.Add(fileContent, "file", fileModel.FileName);

        var response = httpClient.PostAsync("http://localhost:9000/scan", content).Result;
        if (response.IsSuccessStatusCode)
        {
            var responseContent = response.Content.ReadAsStringAsync().Result;
            Console.WriteLine(responseContent);
        }
        else
        {
            Console.WriteLine("File request did not complete: " + response.StatusCode);
        }
    }
}

Conclusion:
In this article, we've covered the process of scanning files using the ClamAV REST API in a .NET Core application. By leveraging Docker to run the ClamAV service and utilizing the HttpClient library, we can easily integrate virus scanning capabilities into our applications.

Remember to handle exceptions and implement error handling according to your application's requirements. This will ensure a robust and reliable file scanning process.