GuilhermeStracini/POC-react-dotnet-UploadStream

using System;
using System.IO;
using Microsoft.Net.Http.Headers;

namespace POCUploadStream.Helpers
{
    public static class MultipartRequestHelper
    {
        // Content-Type: multipart/form-data; boundary="----WebKitFormBoundarymx2fSWqWSd0OxQqq"
        // The spec says 70 characters is a reasonable limit.
        public static string GetBoundary(MediaTypeHeaderValue contentType, int lengthLimit)
        {
            var boundary = HeaderUtilities.RemoveQuotes(contentType.Boundary).ToString();
            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)
        {
            return !string.IsNullOrEmpty(contentType)
                && contentType.IndexOf("multipart/", StringComparison.OrdinalIgnoreCase) >= 0;
        }

        public static bool HasFileContentDisposition(
            ContentDispositionHeaderValue contentDisposition
        )
        {
            // Content-Disposition: form-data; name="anyName"; filename="someFile.jpg"
            return contentDisposition != null
                && contentDisposition.DispositionType.Equals("form-data")
                && (
                    !string.IsNullOrEmpty(contentDisposition.FileName.ToString())
                    || !string.IsNullOrEmpty(contentDisposition.FileNameStar.ToString())
                );
        }
    }
}