Parsing logfile with c# and regex

Question

I have a large log file that looks like the 3 row example below.

\LogFiles\W3SVC1\u_ex12.log:32:2015-01-04 07:11:22 &actor=%7B%22name%22%3A%5B%22Smith%2C%20Steve%22%5D%2C%22mbox%22%3A%5B%22mailto%3ASmith.Steve%40xyz.com%22%5D%7D&
\LogFiles\W3SVC1\u_ex12.log:32:2015-06-08 02:04:13 &actor=%7B%22name%22%3A%5B%22Brown%2C%20Bob%22%5D%2C%22mbox%22%3A%5B%22mailto%3ABrown.Bob%40xyz.com%22%5D%7D&
\LogFiles\W3SVC1\u_ex12.log:32:2014-08-02 05:50:37 &actor=%7B%22name%22%3A%5B%22Franklin%2C%20Francis%22%5D%2C%22mbox%22%3A%5B%22mailto%3AFranklin.Francis%40xyz.com%22%5D%7D&

I need to pull the date, name, and mailto fields that are buried within the log file.

I tried using an online regex generator but only got this far before it seemed to become unwieldy.

using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
  class Program
  {
    static void Main(string[] args)
    {
      //test string
      string txt="\LogFiles\W3SVC1\u_ex12.log:32:2014-08-02 05:50:37 &actor=%7B%22name%22%3A%5B%22Franklin%2C%20Francis%22%5D%2C%22mbox%22%3A%5B%22mailto%3AFranklin.Francis%40xyz.com%22%5D%7D&";

  string re1=".*?"; // Non-greedy match on filler
  string re2="((?:(?:[1]{1}\d{1}\d{1}\d{1})|(?:[2]{1}\d{3}))[-:\/.](?:[0]?[1-9]|[1][012])[-:\/.](?:(?:[0-2]?\d{1})|(?:[3][01]{1})))(?![\d])";   // YYYYMMDD 1

  Regex r = new Regex(re1+re2,RegexOptions.IgnoreCase|RegexOptions.Singleline);
  Match m = r.Match(txt);
  if (m.Success)
  {
        String yyyymmdd1=m.Groups[1].ToString();
        Console.Write("("+yyyymmdd1.ToString()+")"+"
");
  }
  Console.ReadLine();
}
  }
 }

Is there a way to do this in c# with or without regex?

Thanks!

Chief Wiggum · Accepted Answer

What you can do is to split the line into several parts, then decode the url part, get the actor param, deserialize it into an Actor and the use it's properties. An quick example would be:

string txt = @"\LogFiles\W3SVC1\u_ex12.log:32:2014-08-02 05:50:37 &actor=%7B%22name%22%3A%5B%22Franklin%2C%20Francis%22%5D%2C%22mbox%22%3A%5B%22mailto%3AFranklin.Francis%40xyz.com%22%5D%7D&";

var parts = txt.Split(' ');

var urlParams = HttpUtility.UrlDecode(parts[2]);
string actorJson = HttpUtility.ParseQueryString(urlParams).Get("actor");
Actor actor = JsonConvert.DeserializeObject(actorJson);

Console.WriteLine(actor.Name + " " + actor.EmailAddress);

You would need to add a reference to System.Web and Json.Net for it to work and of course a definition for your Actor class like:

namespace MyNamespace
{
    public class Actor
    {
        public string[] name { get; set; }
        public string[] mbox { get; set; }

        public string Name { get { return name[0]; } }
        public string EmailAddress { get { return mbox[0].Replace("mailto:", ""); } }
    }
}

Now you just get all the lines with the File class and loop through each of them an put all deserilized actors into a List or something similar.

Parsing logfile with c# and regex

Answers (2)

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