FileEncoder.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Binary
{
    public class FileEncoder : IContentEncoder
    {
        public FileEncoder()
        {
        }
 
        public string[] ContentTypes => new string[0];
 
        public string[] FileExtensions => new string[0];
 
        public async Task<KeyValuePair<byte[], string>> EncodeAsync(object Object, Encoding Encoding, params string[] AcceptedContentTypes)
        {
            if (Object is FileReference Ref)
            {
                using (FileStream f = File.OpenRead(Ref.FileName))
                {
                    if (f.Length > int.MaxValue)
                        throw new OutOfMemoryException("File too large.");
 
                    byte[] Bin = new byte[f.Length];
                    await f.ReadAsync(Bin, 0, (int)f.Length);
 
                    return new KeyValuePair<byte[], string>(Bin, Ref.ContentType);
                }
            }
            else
                throw new ArgumentException("Unable to encode object.", nameof(Object));
        }
 
        public bool Encodes(object Object, out Grade Grade, params string[] AcceptedContentTypes)
        {
            if (Object is FileReference Ref)
            {
                if (InternetContent.IsAccepted(Ref.ContentType, AcceptedContentTypes))
                {
                    Grade = Grade.Ok;
                    return true;
                }
            }
 
            Grade = Grade.NotAtAll;
            return false;
        }
 
        public bool TryGetContentType(string FileExtension, out string ContentType)
        {
            ContentType = null;
            return false;
        }
 
        public bool TryGetFileExtension(string ContentType, out string FileExtension)
        {
            FileExtension = null;
            return false;
        }
    }
}