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CronParser

Package	NuGet Stable
CronParser

Introduction

CronParser is a C# library designed to parse Cron expressions. It can convert a Cron expression string into a CronExpression object, supporting 5 - part (from minutes to days of the week), 6 - part (from seconds to days of the week), and 7 - part (from seconds to years) Cron expressions.

Features

• Flexible Parsing: Supports Cron expressions of different lengths.
• Input Validation: Rigorously validates the input Cron expression to ensure its validity.
• Error Handling: Catches and handles potential errors during the parsing process, enhancing the robustness of the code.

The corn expression version supported by this library are following:

Five-part format

* * * * *
- - - - -
| | | | |
| | | | |
| | | | +----- Day of week(Range:0-6 or SUN-SAT)
| | | +------- Month(Range: 1-12 or JAN-DEC)
| | +--------- Day of month(Range:1-31)
| +----------- Hour(Range:0-23)
+------------- Minute(Range:0-59)

Six-part format(include second)

* * * * * *
- - - - - -
| | | | | |
| | | | | |
| | | | | +--- Day of week
| | | | +----- Month
| | | +------- Day of month
| | +--------- Hour
| +----------- Minute
+------------- Second(Range:0-59)

Seven-part format

* * * * * * *
- - - - - - -
| | | | | | |
| | | | | | |
| | | | | | +--- Year
| | | | | +----- Day of week
| | | | +------- Month
| | | +--------- Day of month
| | +----------- Hour
| +------------- Minute
+--------------- Second

Cron expression

Field	Required	Allowed values	Allowed special characters	Remarks
Second	No	0-59	* , -,/	* stands every second 3-10 specifies the seconds from 3 to 10. 5/15 specifies the seconds: 5,20,35,50 3,5,7 specifies the seconds: 3,5,7
Minute	Yes	0–59	* , -,/	Similar with above.
Hour	Yes	0–23	* , -,/	Similar with above.
Day of month	Yes	1–31	* , - L	L specifies the last day of the month.
Month	Yes	1–12 or JAN–DEC	* , - /	Similar with second second.
Day of week	Yes	0–6 or SUN–SAT	* , - / L #	5L specifies the last Friday. 5#3 specifies the third Friday of the month.
Year	No	1970–2099	* , - /	Similar with second.

DateTimeOffset time = new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero);
var cronExpression = CronExpressionParser.Parse("0 * * * * *");
var nextTime = cronExpression.GetNextAvaliableTime(time);
Console.WriteLine(nextTime.ToString("yyyy-MM-dd HH:mm:ss"));//2025-01-01 00:01:00

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Cron Wiki for more information on cron expressions.