TextFileEventSink.cs

using System;
using System.IO;
 
namespace Waher.Events.Files
{
    public class TextFileEventSink : TextWriterEventSink
    {
        private StreamWriter file;
        private readonly string fileName;
        private readonly int deleteAfterDays;
 
        public TextFileEventSink(string ObjectID, string FileName)
            : this(ObjectID, FileName, 7)
        {
        }
 
        public TextFileEventSink(string ObjectID, string FileName, int DeleteAfterDays)
            : base(ObjectID, null)
        {
            this.file = null;
            this.output = null;
            this.fileName = FileName;
            this.deleteAfterDays = DeleteAfterDays;
 
            string FolderName = Path.GetDirectoryName(FileName);
 
            if (!Directory.Exists(FolderName))
            {
                Log.Informational("Creating folder.", FolderName);
                Directory.CreateDirectory(FolderName);
            }
        }
 
        protected override void BeforeWrite()
        {
            if (!(this.file is null))
            {
                try
                {
                    this.file?.Dispose();
                }
                catch (Exception)
                {
                    // Ignore
                }
 
                this.file = null;
                this.output = null;
            }
 
            string s = XmlFileEventSink.GetFileName(this.fileName);
 
            if (File.Exists(s))
                this.output = this.file = File.AppendText(s);
            else
            {
                this.output = this.file = File.CreateText(s);
 
                if (this.deleteAfterDays < int.MaxValue)
                {
                    string FolderName = Path.GetDirectoryName(s);
                    if (string.IsNullOrEmpty(FolderName))
                        FolderName = ".";
 
                    string[] Files = Directory.GetFiles(FolderName, "*.*");
 
                    foreach (string FileName in Files)
                    {
                        if ((DateTime.Now - File.GetLastWriteTime(FileName)).TotalDays >= this.deleteAfterDays)
                        {
                            try
                            {
                                File.Delete(FileName);
                            }
                            catch (Exception ex)
                            {
                                Log.Exception(ex);
                            }
                        }
                    }
                }
            }
        }
 
        protected override void AfterWrite()
        {
            this.file.Dispose();
            this.file = null;
        }
 
        public override void DisposeOutput()
        {
            base.DisposeOutput();
 
            this.file?.Dispose();
            this.file = null;
        }
    }
}