Question

I’m parsing some log files to make a report but getting weird results with String.IndexOf() on a few lines. Using C# here. Most easy to explain with some code.

String line = "Jun 29 14:34:19 localhost axis2_http_server: CEF:0|AOPTIX|IRIS|4.1.0.1664.2839|AD214030000301-2610017|114|SDK_ACCESS|4|time=1340980459 comp=10 compinfo=CAPTURE from=8 result=0 user=Admin thread=1305:1962 msg=ation=0.00, faceColor=11.49 HR Face is ICAO compliant, inter-pupil distance=140.00. No match found on LEFT eye (database is empty). LEFT_uid=-1, blacklist=0 No match found on RIGHT eye (database is empty). RIGHT_uid=-1, blacklist=0 CAPTURE successfully completed - SOAP response sent. ";
int ctIndex = line.IndexOf("CaptureTime=");
return ctIndex;

Expected: -1
Actual: 11

This only happens for 2 lines in about a gig of log files.

Actual implemented method

private TimeSpan parseDuration(string line)
{
    int ctIndex = line.IndexOf("CaptureTime=");
    ctIndex = ctIndex + "CaptureTime=".Length;
    int endIndex = line.IndexOf(" ", ctIndex);
    string sDuration = line.Substring(ctIndex, endIndex - ctIndex);
    long duration;
    if (!long.TryParse(sDuration, out duration))
    {
        Console.WriteLine("Error Parsing Duration");
        return TimeSpan.Zero;
    }
    duration *= 1000;
    TimeSpan tsDuration = new TimeSpan(duration*1000);
    return tsDuration;
}

Line Feeding Code

try{
    StreamReader sr = new StreamReader(FilePath);
    string line = sr.ReadLine();
    while(line != null)
    {
         TimeSpan ts = parseDuration(line);
         line = sr.ReadLine();
    }
catch(Exception ex){}
finally{sr.close();}

Answer 1

Your method doesn’t check if ctIndex equals -1 after setting it to line.SubString(). You’re then adding the length of “CaptureTime=” to ctIndex, then preforming a substring.

I would suspect that your code in its current state would not work properly for log messages that don’t contain a CaptureTime= value for those reasons. Is that functional behaviour intended?