Crated basic file upload method; also included appsettings and feauture-management

HaWeb/FileHelpers/MultipartRequestHelper.cs

@@ -0,0 +1,43 @@
+namespace HaWeb.FileHelpers;
+using System;
+using System.IO;
+using Microsoft.Net.Http.Headers;
+
+public static class MultipartRequestHelper
+{
+    // Content-Type: multipart/form-data; boundary="----WebKitFormBoundarymx2fSWqWSd0OxQqq"
+    // The spec at https://tools.ietf.org/html/rfc2046#section-5.1 states that 70 characters is a reasonable limit.
+    public static string GetBoundary(MediaTypeHeaderValue contentType, int lengthLimit)
+    {
+        var boundary = HeaderUtilities.RemoveQuotes(contentType.Boundary).Value;
+
+        if (string.IsNullOrWhiteSpace(boundary))
+            throw new InvalidDataException("Missing content-type boundary.");
+
+        if (boundary.Length > lengthLimit)
+            throw new InvalidDataException($"Multipart boundary length limit {lengthLimit} exceeded.");
+
+        return boundary;
+    }
+
+    public static bool IsMultipartContentType(string? contentType)
+        => !string.IsNullOrEmpty(contentType) && contentType.IndexOf("multipart/", StringComparison.OrdinalIgnoreCase) >= 0;
+
+    public static bool HasFormDataContentDisposition(ContentDispositionHeaderValue contentDisposition)
+    {
+        // Content-Disposition: form-data; name="key";
+        return contentDisposition != null
+            && contentDisposition.DispositionType.Equals("form-data")
+            && string.IsNullOrEmpty(contentDisposition.FileName.Value)
+            && string.IsNullOrEmpty(contentDisposition.FileNameStar.Value);
+    }
+
+    public static bool HasFileContentDisposition(ContentDispositionHeaderValue? contentDisposition)
+    {
+        return contentDisposition != null
+            && contentDisposition.DispositionType.Equals("form-data")
+            && (!string.IsNullOrEmpty(contentDisposition.FileName.Value)
+                || !string.IsNullOrEmpty(contentDisposition.FileNameStar.Value));
+    }
+}
+