Quartz.net RFC 2445或RFC 5545代替CRON

Question

我们有一个运行在.NET中的web服务器，它使用Quartz来调度作业。作业的触发器以RFC 2445格式提供，但是Quartz使用CRON格式。我现在想

• A:找一个可以将我的RFC 2445规则转换成CRON规则的库。
• 相反，把RFC规则交给Quartz吧。

在后一种情况下，我发现了一些Java库，但不是针对.NET的。

我也试着写我自己的图书馆，但我被时间所困。使用RFC2445规则可以定义双周作业(或每三周作业或n-weekly作业)。

FREQ=WEEKLY;BYDAY=MO;INTERVAL=2

也就是说，每隔一个星期一。然而，CRON似乎没有这种功能。

Answer 1

我有一个类似的要求，我找不到一个符合RFC 5545的库来与Quartz调度程序一起工作，最后我按照这一建议实现了一个自定义触发器

在我的例子中，我们使用控件来填充RRULE，但是您也可以对iCal.Net库进行同样的操作。这里并不是完整的实现，但它将使您开始工作，代码是未测试的。

另一个注意事项:如果尝试使用Telerik RecurrenceRule解析它，"FREQ=WEEKLY;BYDAY=MO;INTERVAL=2“可能会失败，因为它缺少DTSTART、DTEND等。这是一个不会失败的重复规则字符串的示例："DTSTART:20210309T050000Z\r\nDTEND:20210309T060000Z\r\nRRULE:FREQ=WEEKLY;BYDAY=TU;INTERVAL=1"。

您需要实现ITrigger接口。其中许多内容可以从CroneTriggerImpl类中复制和修改。

public interface IRRuleTrigger : ITrigger
{
    string RecurrenceRuleString { get; set; }
} 

然后，您需要从AbstractTrigger继承的实现类。

public class MyTriggerImpl: AbstractTrigger, IRRuleTrigger
{
   //implement all members here. Look at CronTriggerImpl class in Quartz.Net source. I'm pasting some of the implementation code but not all.
   //...

    private RecurrenceRule rRule;

    /// <summary>
    /// Gets or sets the RRULE expression string.
    /// </summary>
    /// <value>The expression string.</value>
    public string RecurrenceRuleString
    {
        set
        {
            TimeZoneInfo originalTimeZone = TimeZone;
            var success = RecurrenceRule.TryParse(value, out var parsedRule);
            if(success) rRule = parsedRule ;// RecurrenceRule(value!);
        }
        get => rRule?.ToString();
    }


    /// <summary>
    /// Gets or sets the RRULE expression string.
    /// </summary>
    /// <value>The expression string like RRULE:FREQ=WEEKLY;BYDAY=MO;INTERVAL=2.</value>
    public string RecurrenceRuleString
    {
        set
        {
            TimeZoneInfo originalTimeZone = TimeZone;
            var success = RecurrenceRule.TryParse(value, out var parsedRule);
            if(success) rRule = parsedRule ;// RecurrenceRule(value!);
        }
        get => rRule?.ToString();
    }

    ////////////////////////////////////////////////////////////////////////////
    //
    // Computation Functions
    //
    ////////////////////////////////////////////////////////////////////////////

    /// <summary>
    /// Gets the next time to fire after the given time.
    /// </summary>
    /// <param name="afterTime">The time to compute from.</param>
    /// <returns></returns>
    protected DateTimeOffset? GetTimeAfter(DateTimeOffset afterTime)
    {
        return rRule?.HasOccurrences == true ?
            rRule?.Occurrences.Where(o => o > afterTime).Min()
            : null;
    }

    /// <summary>
    /// Returns the time before the given time
    /// that this <see cref="IRRuleTrigger" /> will fire.
    /// </summary>
    /// <param name="date">The date.</param>
    /// <returns></returns>
    protected DateTimeOffset? GetTimeBefore(DateTimeOffset? date)
    {
        return rRule?.HasOccurrences == true ? 
            rRule?.Occurrences.Where(o=> o < date).Max()
            : null;
    }
}

public class RRuleScheduleBuilder : ScheduleBuilder<IRRuleTrigger>
{
    private int misfireInstruction = MisfireInstruction.SmartPolicy;
    private RecurrenceRule recurrenceRule;

    public override IMutableTrigger Build()
    {
        MyTriggerImpl myTriggerImpl = new MyTriggerImpl();


        myTriggerImpl.MisfireInstruction = misfireInstruction;
        myTriggerImpl.RecurrenceRuleString = this.recurrenceRule.ToString();
        return myTriggerImpl;
    }
    /// <summary>
    /// Create a RRuleScheduleBuilder with the given string expression - which
    /// is presumed to be valid expression (and hence only a RuntimeException
    /// will be thrown if it is not).
    /// </summary>
    /// <remarks>
    /// </remarks>
    /// <param name="recurrenceRuleString">the RRule expression to base the schedule on.</param>
    /// <returns>the new RRuleScheduleBuilder</returns>
    public static RRuleScheduleBuilder RecurrenceRuleSchedule(string recurrenceRuleString)
    {
        var success = RecurrenceRule.TryParse(recurrenceRuleString, out var rRule);
        if(!success) throw new ArgumentException($"Recurrence Rule String ({recurrenceRuleString}) is invalid.");
        return new RRuleScheduleBuilder(rRule);
    }

    protected RRuleScheduleBuilder(RecurrenceRule rule)
    {
        this.recurrenceRule = rule ?? throw new ArgumentNullException(nameof(rule), "recurrenceRule cannot be null");
    }
}
/// <summary>
/// Extension methods that attach <see cref="RRuleScheduleBuilder" /> to <see cref="TriggerBuilder" />.
/// </summary>
public static class RRuleScheduleTriggerBuilderExtensions
{
    public static TriggerBuilder WithRRuleSchedule(this TriggerBuilder triggerBuilder, string recurrenceRuleString)
    {
        RRuleScheduleBuilder builder = RRuleScheduleBuilder.RecurrenceRuleSchedule(recurrenceRuleString);
        return triggerBuilder.WithSchedule(builder);
    }

    public static TriggerBuilder WithRRuleSchedule(this TriggerBuilder triggerBuilder, string recurrenceRuleString, Action<RRuleScheduleBuilder> action)
    {
        RRuleScheduleBuilder builder = RRuleScheduleBuilder.RecurrenceRuleSchedule(recurrenceRuleString);
        action(builder);
        return triggerBuilder.WithSchedule(builder);
    }
}

实现之后，您可以像这样创建和使用触发器：

        // Grab the Scheduler instance from the Factory
        StdSchedulerFactory factory = new StdSchedulerFactory();
        var scheduler = await factory.GetScheduler();
        await scheduler.Start();

        var job = JobBuilder.Create<MyBusinessClassThatImplementsIJobInterface>()
            .WithIdentity("someIdentity", "someGroupName")
            .Build();

        var trigger = (IRRuleTrigger)TriggerBuilder.Create()
            .WithIdentity("someName", "myGroup")
            .WithRRuleSchedule(rule.ToString())
            .Build();

        await scheduler.ScheduleJob(job, trigger);