ncrontab - Crontab for .NET - Google Project Hosting
A library written in C# 3.0 that provides the following facilities:
- Parsing of crontab expressions
- Formatting of crontab expressions
- Calculation of occurrences of time based on a crontab schedule
This library does not provide any scheduler or is not a scheduling facility like cron from Unix platforms. What it provides is parsing, formatting and an algorithm to produce occurrences of time based on a give schedule expressed in the crontab format:
* * * * *
- - - - -
| | | | |
| | | | +----- day of week ( 0 - 6 ) ( Sunday = 0 )
| | | +------- month ( 1 - 12 )
| | +--------- day of month ( 1 - 31 )
| +----------- hour ( 0 - 23 )
+------------- min ( 0 - 59 )Star ( * ) in the value field above means all legal values as in parentheses for that column. The value column can have a * or a list of elements separated by commas. An element is either a number in the ranges shown above or two numbers in the range separated by a hyphen (meaning an inclusive range). For more, see CrontabExpression .
Below is an example in IronPython of how to use CrontabSchedule class from NCrontab to generate occurrences of the schedule 0 12 * */2 Mon (meaning, 12:00 PM on Monday of every other month, starting with January ) throughout the year 2000:
IronPython 1.1 ( 1.1 ) on . NET 2.0 . 50727.1434
Copyright ( c ) Microsoft Corporation . All rights reserved .
>>> import clr
>>> clr . AddReferenceToFileAndPath ( r 'C:\NCrontab\bin\Release\NCrontab.dll' )
>>> from System import DateTime
>>> from NCrontab import CrontabSchedule
>>> s = CrontabSchedule . Parse ( '0 12 * */2 Mon' )
>>> start = DateTime ( 2000 , 1 , 1 )
>>> end = start . AddYears ( 1 )
>>> occurrences = s . GetNextOccurrences ( start , end )
>>> print '\n' . join ([ t . ToString ( 'ddd, dd MMM yyyy hh:mm' ) for t in occurrences ])
Mon , 03 Jan 2000 12 : 00
Mon , 10 Jan 2000 12 : 00
Mon , 17 Jan 2000 12 : 00
Mon , 24 Jan 2000 12 : 00
Mon , 31 Jan 2000 12 : 00
Mon , 06 Mar 2000 12 : 00
Mon , 13 Mar 2000 12 : 00
Mon , 20 Mar 2000 12 : 00
Mon , 27 Mar 2000 12 : 00
Mon , 01 May 2000 12 : 00
Mon , 08 May 2000 12 : 00
Mon , 15 May 2000 12 : 00
Mon , 22 May 2000 12 : 00
Mon , 29 May 2000 12 : 00
Mon , 03 Jul 2000 12 : 00
Mon , 10 Jul 2000 12 : 00
Mon , 17 Jul 2000 12 : 00
Mon , 24 Jul 2000 12 : 00
Mon , 31 Jul 2000 12 : 00
Mon , 04 Sep 2000 12 : 00
Mon , 11 Sep 2000 12 : 00
Mon , 18 Sep 2000 12 : 00
Mon , 25 Sep 2000 12 : 00
Mon , 06 Nov 2000 12 : 00
Mon , 13 Nov 2000 12 : 00
Mon , 20 Nov 2000 12 : 00
Mon , 27 Nov 2000 12 : 00Below is the same example in F# Interactive ( fsi.exe ):
Microsoft ( R ) F # 2.0 Interactive build 4.0.40219.1
Copyright ( c ) Microsoft Corporation . All Rights Reserved .
For help type #help;;
> #r "NCrontab.dll"
-
- open NCrontab
- open System
-
- let schedule = CrontabSchedule . Parse ( "0 12 * */2 Mon" )
- let startDate = DateTime ( 2000 , 1 , 1 )
- let endDate = startDate . AddYears ( 1 )
-
- let occurrences = schedule . GetNextOccurrences ( startDate , endDate )
- occurrences |> Seq . map ( fun t -> t . ToString ( "ddd, dd MMM yyy hh:mm" ))
- |> String . concat "\n"
- |> printfn "%s" ;;
--> Referenced 'C:\NCrontab\bin\Release\NCrontab.dll'
Mon , 03 Jan 2000 12 : 00
Mon , 10 Jan 2000 12 : 00
Mon , 17 Jan 2000 12 : 00
Mon , 24 Jan 2000 12 : 00
Mon , 31 Jan 2000 12 : 00
Mon , 06 Mar 2000 12 : 00
Mon , 13 Mar 2000 12 : 00
Mon , 20 Mar 2000 12 : 00
Mon , 27 Mar 2000 12 : 00
Mon , 01 May 2000 12 : 00
Mon , 08 May 2000 12 : 00
Mon , 15 May 2000 12 : 00
Mon , 22 May 2000 12 : 00
Mon , 29 May 2000 12 : 00
Mon , 03 Jul 2000 12 : 00
Mon , 10 Jul 2000 12 : 00
Mon , 17 Jul 2000 12 : 00
Mon , 24 Jul 2000 12 : 00
Mon , 31 Jul 2000 12 : 00
Mon , 04 Sep 2000 12 : 00
Mon , 11 Sep 2000 12 : 00
Mon , 18 Sep 2000 12 : 00
Mon , 25 Sep 2000 12 : 00
Mon , 06 Nov 2000 12 : 00
Mon , 13 Nov 2000 12 : 00
Mon , 20 Nov 2000 12 : 00
Mon , 27 Nov 2000 12 : 00
val schedule : NCrontab . CrontabSchedule = 0 12 * 1 , 3 , 5 , 7 , 9 , 11 1
val startDate : System . DateTime = 1 / 1 / 2000 12 : 00 : 00 AM
val endDate : System . DateTime = 1 / 1 / 2001 12 : 00 : 00 AM
val occurrences : seq < System . DateTime >
