initial commit of a worker skeleton

MalwareMultiScan.Backends/Backends/Abstracts/AbstractScanBackend.cs

@@ -0,0 +1,54 @@
+using System;
+using System.IO;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using MalwareMultiScan.Shared.Interfaces;
+using Microsoft.AspNetCore.Http;
+
+namespace MalwareMultiScan.Backends.Backends.Abstracts
+{
+    public abstract class AbstractScanBackend : IScanBackend
+    {
+        public virtual string Name => throw new NotImplementedException();
+        
+        public virtual DateTime DatabaseLastUpdate => throw new NotImplementedException();
+        
+        public virtual Task<string[]> ScanAsync(string path, CancellationToken cancellationToken)
+        {
+            throw new NotImplementedException();
+        }
+
+        public async Task<string[]> ScanAsync(Uri uri, CancellationToken cancellationToken)
+        {
+            using var httpClient = new HttpClient();
+            await using var uriStream = await httpClient.GetStreamAsync(uri);
+            
+            return await ScanAsync(uriStream, cancellationToken);
+        }
+
+        public async Task<string[]> ScanAsync(IFormFile file, CancellationToken cancellationToken)
+        {
+            await using var fileStream = file.OpenReadStream();
+            
+            return await ScanAsync(fileStream, cancellationToken);
+        }
+
+        public async Task<string[]> ScanAsync(Stream stream, CancellationToken cancellationToken)
+        {
+            var tempFile = Path.GetTempFileName();
+
+            try
+            {
+                await using (var tempFileStream = File.OpenWrite(tempFile))
+                    await stream.CopyToAsync(tempFileStream, cancellationToken);
+
+                return await ScanAsync(tempFile, cancellationToken);
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+    }
+}