FileResource.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Waher.Content;
using Waher.Content.Binary;
using Waher.Networking.HTTP.Mcp.Model.Server;
using Waher.Runtime.IO;
 
namespace Waher.Networking.HTTP.Mcp.Model.Resources
{
    public class FileResource : Resource
    {
        private readonly string fileName;
        private readonly bool isTextFile;
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, null, GetContentType(FileName), MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        private static string GetContentType(string FileName)
        {
            if (InternetContent.TryGetContentType(Path.GetExtension(FileName),
                out string? ContentType))
            {
                return ContentType;
            }
            else
                return BinaryCodec.DefaultContentType;
        }
 
        private bool IsTextFile()
        {
            return IsTextFile(this.ContentType);
        }
 
        public static bool IsTextFile(string? ContentType)
        { 
            if (ContentType is null)
                return false;
            else if (ContentType.StartsWith("text/"))
                return true;
            else if (ContentType.StartsWith("application/"))
            {
                string s = ContentType;
                int i = s.IndexOf(';', 12);
                if (i > 0)
                    s = s[..i].TrimEnd();
 
                if (s.EndsWith("xml") ||
                    s.EndsWith("json") ||
                    s.EndsWith("script") ||
                    s.EndsWith("tlv") ||
                    s.EndsWith("turtle") ||
                    s.EndsWith("latex"))
                {
                    return true;
                }
                else
                {
                    switch (s)
                    {
                        case "application/x-www-form-urlencoded":
                        case "application/link-format":
                        case "application/jwt":
                        case "application/sparql-query":
                            return true;
 
                        default:
                            return false;
                    }
                }
            }
            else
                return false;
        }
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, string? RequiredPrivilege,
            params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, RequiredPrivilege,
                  GetContentType(FileName), MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, string? RequiredPrivilege, long? Size,
            params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, RequiredPrivilege,
                  GetContentType(FileName), Size, MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, string? RequiredPrivilege, long? Size, Icon Icon,
            params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, RequiredPrivilege,
                  GetContentType(FileName), Size, Icon, MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, string? RequiredPrivilege, long? Size, Icons? Icons,
            params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, RequiredPrivilege,
                  GetContentType(FileName), Size, Icons, MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        public FileResource(string Name, string Title, string Description, Uri Uri,
            string FileName, string? RequiredPrivilege, long? Size, Icons? Icons,
            McpRole[]? Audience, double? Priority, DateTime? LastModified,
            params KeyValuePair<string, object>[] MetaData)
            : base(Name, Title, Description, Uri, RequiredPrivilege,
                  GetContentType(FileName), Size, Icons, Audience, Priority, LastModified,
                  MetaData)
        {
            this.fileName = FileName;
            this.isTextFile = this.IsTextFile();
        }
 
        public override async Task<IResourceContent[]> Read(
            Dictionary<string, object>? MetaData)
        {
            if (this.isTextFile)
            {
                string s = await Files.ReadAllTextAsync(this.fileName);
 
                return new IResourceContent[]
                {
                    new TextContent(this.Uri, s, this.ContentType, MetaData)
                };
            }
            else
            {
                byte[] Bin = await Files.ReadAllBytesAsync(this.fileName);
 
                return new IResourceContent[]
                {
                    new BlobContent(this.Uri, Bin,
                        this.ContentType ?? BinaryCodec.DefaultContentType, MetaData)
                };
            }
        }
    }
}