cron_expression Class Reference

Strongly-typed, validated cron expression. More...

#include <cron_expression.hpp>

Collaboration diagram for cron_expression:

Public Member Functions
	cron_expression ()
	Default constructor. Creates an expression that runs every minute.
const std::string &	to_string () const noexcept
	The validated cron string, suitable for pg_cron's cron.schedule().
std::chrono::system_clock::time_point	next_occurrence (std::chrono::system_clock::time_point after=std::chrono::system_clock::now()) const
	Compute the next occurrence after the given time point.
bool	operator== (const cron_expression &other) const noexcept=default

Static Public Member Functions
static std::expected< cron_expression, std::string >	from_string (std::string_view expr)
	Parse and validate a cron expression string.

Detailed Description

Strongly-typed, validated cron expression.

Wraps a cron expression string, validating it on construction via croncpp. Provides C++23 chrono-based next-occurrence computation and serialisation to the plain string required by pg_cron's cron.schedule() function.

Use the factory method from_string() to construct:

auto expr = cron_expression::from_string("0 0 * * *");
if (expr) {
    auto next = expr->next_occurrence();
}

Constructor & Destructor Documentation

cron_expression()

cron_expression

(

)

Default constructor. Creates an expression that runs every minute.

Provides a valid default state so that types containing cron_expression (e.g. job_definition) can be default-constructed for UI purposes. Equivalent to "* * * * *".

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Member Function Documentation

from_string()

std::expected< cron_expression, std::string > from_string ( std::string_view  expr )

static

Parse and validate a cron expression string.

Accepts standard 5-field cron syntax (minute hour day month weekday). Returns an error string if the expression is malformed.

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next_occurrence()

std::chrono::system_clock::time_point next_occurrence

(

std::chrono::system_clock::time_point

after = std::chrono::system_clock::now()

)

const

Compute the next occurrence after the given time point.

Defaults to the current wall-clock time when no argument is supplied.