CsvCodec.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using Waher.Runtime.Inventory;
using Waher.Script.Abstraction.Elements;
 
namespace Waher.Content.Text
{
    public class CsvCodec : IContentDecoder, IContentEncoder
    {
        public CsvCodec()
        {
        }
 
        public const string ContentType = "text/csv";
 
        public static readonly string[] CsvContentTypes = new string[] { ContentType };
 
        public static readonly string[] CsvFileExtensions = new string[] { "csv" };
 
        public string[] ContentTypes => CsvContentTypes;
 
        public string[] FileExtensions => CsvFileExtensions;
 
        public bool Decodes(string ContentType, out Grade Grade)
        {
            if (ContentType == CsvCodec.ContentType)
            {
                Grade = Grade.Excellent;
                return true;
            }
            else
            {
                Grade = Grade.NotAtAll;
                return false;
            }
        }
 
        public Task<object> DecodeAsync(string ContentType, byte[] Data, Encoding Encoding, KeyValuePair<string, string>[] Fields, Uri BaseUri)
        {
            string s = CommonTypes.GetString(Data, Encoding);
            return Task.FromResult<object>(CSV.Parse(s));
        }
 
 
        public bool TryGetContentType(string FileExtension, out string ContentType)
        {
            if (string.Compare(FileExtension, "csv", true) == 0)
            {
                ContentType = CsvCodec.ContentType;
                return true;
            }
            else
            {
                ContentType = null;
                return false;
            }
        }
 
        public bool TryGetFileExtension(string ContentType, out string FileExtension)
        {
            switch (ContentType.ToLower())
            {
                case CsvCodec.ContentType:
                    FileExtension = "csv";
                    return true;
 
                default:
                    FileExtension = string.Empty;
                    return false;
            }
        }
 
        public bool Encodes(object Object, out Grade Grade, params string[] AcceptedContentTypes)
        {
            if (InternetContent.IsAccepted(CsvContentTypes, AcceptedContentTypes) &&
                (Object is string[][] || Object is IMatrix))
            {
                Grade = Grade.Ok;
                return true;
            }
            else
            {
                Grade = Grade.NotAtAll;
                return false;
            }
        }
 
        public Task<KeyValuePair<byte[], string>> EncodeAsync(object Object, Encoding Encoding, params string[] AcceptedContentTypes)
        {
            string Csv;
 
            if (Object is string[][] Records)
                Csv = CSV.Encode(Records);
            else if (Object is IMatrix M)
                Csv = CSV.Encode(M);
            else
                throw new ArgumentException("Unable to encode as CSV.", nameof(Object));
 
            if (Encoding is null)
                Encoding = Encoding.UTF8;
 
            return Task.FromResult(new KeyValuePair<byte[], string>(Encoding.GetBytes(Csv), ContentType));
        }
    }
}