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Introduction
============
Pallets Community Ecosystem
===========================
.. important::
This project is part of the Pallets Community Ecosystem. Pallets is the
open
source organization that maintains Flask; Pallets-Eco enables community
maintenance of Flask extensions. If you are interested in helping
maintain
this project, please reach out on the [Pallets Discord server
].
Usage
============
A simple example::
>>> from croniter import croniter
>>> from datetime import datetime
>>> base = datetime(2010, 1, 25, 4, 46)
>>> iter = croniter('*/5 * * * *', base) # every 5 minutes
>>> print(iter.get_next(datetime)) # 2010-01-25 04:50:00
>>> print(iter.get_next(datetime)) # 2010-01-25 04:55:00
>>> print(iter.get_next(datetime)) # 2010-01-25 05:00:00
>>>
>>> iter = croniter('2 4 * * mon,fri', base) # 04:02 on every Monday
and Friday
>>> print(iter.get_next(datetime)) # 2010-01-26 04:02:00
>>> print(iter.get_next(datetime)) # 2010-01-30 04:02:00
>>> print(iter.get_next(datetime)) # 2010-02-02 04:02:00
>>>
>>> iter = croniter('2 4 1 * wed', base) # 04:02 on every Wednesday OR
on 1st day of month
>>> print(iter.get_next(datetime)) # 2010-01-27 04:02:00
>>> print(iter.get_next(datetime)) # 2010-02-01 04:02:00
>>> print(iter.get_next(datetime)) # 2010-02-03 04:02:00
>>>
>>> iter = croniter('2 4 1 * wed', base, day_or=False) # 04:02 on
every 1st day of the month if it is a Wednesday
>>> print(iter.get_next(datetime)) # 2010-09-01 04:02:00
>>> print(iter.get_next(datetime)) # 2010-12-01 04:02:00
>>> print(iter.get_next(datetime)) # 2011-06-01 04:02:00
>>>
>>> iter = croniter('0 0 * * sat#1,sun#2', base) # 1st Saturday, and
2nd Sunday of the month
>>> print(iter.get_next(datetime)) # 2010-02-06 00:00:00
>>>
>>> iter = croniter('0 0 * * 5#3,L5', base) # 3rd and last Friday of
the month
>>> print(iter.get_next(datetime)) # 2010-01-29 00:00:00
>>> print(iter.get_next(datetime)) # 2010-02-19 00:00:00
All you need to know is how to use the constructor and the get_next
method, the signature of these methods are listed below::
>>> def __init__(self, cron_format, start_time=time.time(),
day_or=True)
croniter iterates along with cron_format from start_time.
cron_format is **min hour day month day_of_week**, you can refer to
http://en.wikipedia.org/wiki/Cron for more details. The day_or
switch is used to control how croniter handles **day** and **day_of_week**
entries. Default option is the cron behaviour, which connects those
values using **OR**. If the switch is set to False, the values are
connected
using **AND**. This behaves like fcron and enables you to e.g. define a job
that
executes each 2nd Friday of a month by setting the days of month and the
weekday.
::
>>> def get_next(self, ret_type=float)
get_next calculates the next value according to the cron expression and
returns an object of type ret_type. ret_type should be a float or a
datetime object.
Supported added for get_prev method. (>= 0.2.0)::
>>> base = datetime(2010, 8, 25)
>>> itr = croniter('0 0 1 * *', base)
>>> print(itr.get_prev(datetime)) # 2010-08-01 00:00:00
>>> print(itr.get_prev(datetime)) # 2010-07-01 00:00:00
>>> print(itr.get_prev(datetime)) # 2010-06-01 00:00:00
You can validate your crons using is_valid class method. (>= 0.3.18)::
>>> croniter.is_valid('0 0 1 * *') # True
>>> croniter.is_valid('0 wrong_value 1 * *') # False
Strict validation
-----------------
By default, is_valid and expand only check that each field is within its
own range
(e.g. day 1-31, month 1-12). They do not cross-validate fields, so
expressions like
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