EventExtensions.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using Waher.Content;
using Waher.Content.Xml;
 
namespace Waher.Events.Files
{
    public static class EventExtensions
    {
        public const string LogNamespace = "http://waher.se/Schema/EventOutput.xsd";
 
        public static string ToXML(this Event Event)
        {
            StringBuilder sb = new StringBuilder();
            Event.ToXML(sb);
            return sb.ToString();
        }
 
        public static void ToXML(this Event Event, StringBuilder Xml)
        {
            string ElementName = Event.Type.ToString();
 
            Xml.Append('<');
            Xml.Append(ElementName);
            Xml.Append(" xmlns='");
            Xml.Append(LogNamespace);
            Xml.Append("' timestamp='");
            Xml.Append(XML.Encode(Event.Timestamp));
            Xml.Append("' level='");
            Xml.Append(Event.Level.ToString());
 
            if (!string.IsNullOrEmpty(Event.EventId))
            {
                Xml.Append("' id='");
                Xml.Append(Event.EventId);
            }
 
            if (!string.IsNullOrEmpty(Event.Object))
            {
                Xml.Append("' object='");
                Xml.Append(Event.Object);
            }
 
            if (!string.IsNullOrEmpty(Event.Actor))
            {
                Xml.Append("' actor='");
                Xml.Append(Event.Actor);
            }
 
            if (!string.IsNullOrEmpty(Event.Module))
            {
                Xml.Append("' module='");
                Xml.Append(Event.Module);
            }
 
            if (!string.IsNullOrEmpty(Event.Facility))
            {
                Xml.Append("' facility='");
                Xml.Append(Event.Facility);
            }
 
            Xml.Append("'><Message>");
 
            foreach (string Row in GetRows(Event.Message))
            {
                Xml.Append("<Row>");
                Xml.Append(XML.Encode(Row));
                Xml.Append("</Row>");
            }
 
            Xml.Append("</Message>");
 
            if (!(Event.Tags is null) && Event.Tags.Length > 0)
            {
                foreach (KeyValuePair<string, object> Tag in Event.Tags)
                {
                    Xml.Append("<Tag key='");
                    Xml.Append(XML.Encode(Tag.Key));
 
                    if (!(Tag.Value is null))
                    {
                        Xml.Append("' value='");
                        Xml.Append(XML.Encode(Tag.Value.ToString()));
                    }
 
                    Xml.Append("'/>");
                }
            }
 
            if (Event.Type >= EventType.Critical && !string.IsNullOrEmpty(Event.StackTrace))
            {
                Xml.Append("<StackTrace>");
 
                foreach (string Row in GetRows(Event.StackTrace))
                {
                    Xml.Append("<Row>");
                    Xml.Append(XML.Encode(Row));
                    Xml.Append("</Row>");
                }
 
                Xml.Append("</StackTrace>");
            }
 
            Xml.Append("</");
            Xml.Append(ElementName);
            Xml.Append('>');
        }
 
        internal static string[] GetRows(string s)
        {
            return s.Replace("\r\n", "\n").Replace("\r", "\n").Split('\n');
        }
 
        public static bool TryParse(string Xml, out Event[] Parsed)
        {
            XmlDocument Doc = new XmlDocument();
            Doc.LoadXml(Xml);
            return TryParse(Xml, out Parsed);
        }
 
        public static bool TryParse(XmlDocument Xml, out Event[] Parsed)
        {
            Parsed = null;
 
            if (Xml.DocumentElement is null || Xml.DocumentElement.NamespaceURI != LogNamespace)
                return false;
 
            if (Xml.DocumentElement.LocalName == "EventOutput")
            {
                List<Event> List = new List<Event>();
 
                foreach (XmlNode N in Xml.DocumentElement.ChildNodes)
                {
                    if (!(N is XmlElement E))
                        continue;
 
                    if (!TryParse(E, out Event ParsedElement))
                        return false;
 
                    List.Add(ParsedElement);
                }
 
                Parsed = List.ToArray();
                return true;
            }
            else if (TryParse(Xml.DocumentElement, out Event ParsedElement))
            {
                Parsed = new Event[] { ParsedElement };
                return true;
            }
            else
                return false;
        }
 
 
        public static bool TryParse(XmlElement Xml, out Event Parsed)
        {
            if (Xml is null || Xml.NamespaceURI != LogNamespace)
            {
                Parsed = null;
                return false;
            }
 
            DateTime Timestamp = XML.Attribute(Xml, "timestamp", DateTime.Now);
            EventLevel Level = XML.Attribute(Xml, "level", EventLevel.Minor);
            string EventId = XML.Attribute(Xml, "id");
            string Object = XML.Attribute(Xml, "object");
            string Actor = XML.Attribute(Xml, "actor");
            string Module = XML.Attribute(Xml, "module");
            string Facility = XML.Attribute(Xml, "facility");
            string StackTrace = null;
            string Message = null;
            List<KeyValuePair<string, object>> Tags = new List<KeyValuePair<string, object>>();
 
            foreach (XmlNode N2 in Xml.ChildNodes)
            {
                if (!(N2 is XmlElement E2))
                    continue;
 
                switch (E2.LocalName)
                {
                    case "Message":
                        Message = ReadRows(E2);
                        break;
 
                    case "StackTrace":
                        StackTrace = ReadRows(E2);
                        break;
 
                    case "Tag":
                        string Key = XML.Attribute(E2, "key");
                        string Value = XML.Attribute(E2, "value");
 
                        if (bool.TryParse(Value, out bool b))
                            Tags.Add(new KeyValuePair<string, object>(Key, b));
                        else if (int.TryParse(Value, out int i))
                            Tags.Add(new KeyValuePair<string, object>(Key, i));
                        else if (long.TryParse(Value, out long l))
                            Tags.Add(new KeyValuePair<string, object>(Key, l));
                        else if (double.TryParse(Value, out double d))
                            Tags.Add(new KeyValuePair<string, object>(Key, d));
                        else
                            Tags.Add(new KeyValuePair<string, object>(Key, Value));
                        break;
                }
            }
 
            if (!Enum.TryParse(Xml.LocalName, out EventType EventType))
            {
                Parsed = null;
                return false;
            }
 
            Parsed = new Event(Timestamp, EventType, Message ?? string.Empty, Object, Actor,
                EventId, Level, Facility, Module, StackTrace, Tags.ToArray());
 
            return true;
        }
 
        private static string ReadRows(XmlElement E)
        {
            StringBuilder sb = new StringBuilder();
            bool First = true;
 
            foreach (XmlNode N in E.ChildNodes)
            {
                if (!(N is XmlElement E2))
                    continue;
 
                if (E2.LocalName == "Row")
                {
                    if (First)
                        First = false;
                    else
                        sb.AppendLine();
 
                    sb.Append(E2.InnerText);
                }
            }
 
            return sb.ToString();
        }
    }
}