holidays_jp

holidays_jp is both a Rust library and command-line tool for determining Japanese national holidays. It provides a simple and efficient way to check if specific dates are holidays, list holidays within date ranges, and manage holiday data.

Features

• 🗓️ Flexible Date Formats: Supports multiple date formats (YYYYMMDD, YYYY-MM-DD, YYYY/MM/DD, YYYY年MM月DD日, etc.)
• 📊 Multiple Output Formats: Human-readable, JSON, and quiet modes
• 📅 Date Range Support: List all holidays within a specified period
• 🔄 Auto-Update: Automatically updates holiday data from official sources
• 🌐 Offline Support: Works without internet connection after initial setup
• ⚡ Fast & Lightweight: Quick response times and minimal resource usage

Data Source

The holiday data is based on the official CSV file provided by the Cabinet Office of Japan. The data is automatically updated once a week via GitHub Actions, ensuring you always have the latest holiday information.

Note: The data source URL is configurable via config.toml. See the configuration section for details.

Installation

As a Library

Add this to your Cargo.toml:

[dependencies]
holidays_jp = "0.3"
tokio = { version = "1", features = ["rt-multi-thread", "macros"] }

As a CLI Tool

From Source

git clone https://github.com/nabetama/holidays_jp.git
cd holidays_jp
cargo build --release

Using Cargo

cargo install holidays_jp

Quick Start

Library Usage

Check if a specific date is a holiday

use holidays_jp::{HolidayService, Config};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Initialize the service with default configuration
    let config = Config::default();
    let mut service = HolidayService::new(config);
    service.initialize().await?;

    // Check if a specific date is a holiday
    let (is_holiday, holiday_name) = service.get_holiday("2023-01-01")?;
    if is_holiday {
        println!("2023-01-01 is a holiday: {}", holiday_name.unwrap());
    } else {
        println!("2023-01-01 is not a holiday");
    }

    Ok(())
}

List holidays in a date range

use holidays_jp::{HolidayService, Config};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config = Config::default();
    let mut service = HolidayService::new(config);
    service.initialize().await?;

    // Get all holidays in 2023
    let holidays = service.get_holidays_in_range("2023-01-01", "2023-12-31")?;
    for (date, name) in holidays {
        println!("{}: {}", date, name);
    }

    Ok(())
}

CLI Usage

If your PC is connected to the Internet, you can obtain the latest Japanese national holiday data by executing the following command.

cargo run -- update

# Check today's date (default behavior)
holidays_jp
20251014 is not a holiday

# Check a specific date (with -d option)
holidays_jp check -d 20220101
20220101 is holiday(元日)

# Check a specific date (positional argument, no -d required)
holidays_jp check 20220101
20220101 is holiday(元日)

# Check with different date format
holidays_jp check 2022/01/01
2022/01/01 is holiday(元日)

# JSON output for scripting
holidays_jp check 2022-01-01 -o json
{"date":"2022-01-01","is_holiday":true,"holiday_name":"元日"}

# Quiet output (holiday name only)
holidays_jp check 2022-01-01 -o quiet
元日

# Verbose output with additional information
holidays_jp check 2022-01-01 -v
Checking date: 2022-01-01
Configuration loaded successfully
Holiday data loaded: 123 holidays
2022-01-01 is holiday(元日)

List Holidays in a Range

# List holidays in January 2023
holidays_jp list --start 2023-01-01 --end 2023-01-31
Holidays in range (2023-01-01 to 2023-01-31):
  2023-01-01 - 元日
  2023-01-02 - 休日
  2023-01-09 - 成人の日

# JSON output for programmatic use
holidays_jp list --start 2023-01-01 --end 2023-01-31 -o json
{
  "start_date": "2023-01-01",
  "end_date": "2023-01-31",
  "holidays": [
    {
      "date": "2023-01-01",
      "is_holiday": true,
      "holiday_name": "元日"
    },
    {
      "date": "2023-01-02",
      "is_holiday": true,
      "holiday_name": "休日"
    },
    {
      "date": "2023-01-09",
      "is_holiday": true,
      "holiday_name": "成人の日"
    }
  ]
}

# List all holidays in 2023
holidays_jp list --start 2023/01/01 --end 2023/12/31

Update Holiday Data

# Update to the latest holiday data
holidays_jp update
🔄 Updating holiday data from official source...
✅ Holiday data updated successfully!

Get Help

# General help
holidays_jp --help

# Command-specific help
holidays_jp check --help
holidays_jp list --help
holidays_jp update --help

Supported Date Formats

The tool automatically detects and supports various date formats:

• YYYYMMDD (e.g., 20230101)
• YYYY-MM-DD (e.g., 2023-01-01)
• YYYY/MM/DD (e.g., 2023/01/01)
• YYYY年MM月DD日 (e.g., 2023年1月1日)
• MM/DD/YYYY (e.g., 01/01/2023)
• DD/MM/YYYY (e.g., 01/01/2023)
• YYYY.MM.DD (e.g., 2023.01.01)

Output Formats

• human (default): Human-readable format with clear messages
• json: Structured JSON output for programmatic use
• quiet: Minimal output showing only holiday names

Configuration

The application automatically generates a config.toml file on first run with default settings. You can customize this file to fit your needs.

Configuration File Location

• Auto-generated: config.toml (created automatically on first run)
• Example/Template: config.toml.example (reference configuration with detailed comments)

Configuration Options

[holiday_data]
# Data source URL (configurable)
source_url = "https://www8.cao.go.jp/chosei/shukujitsu/syukujitsu.csv"
# Cache file location
cache_file = "./data/holidays.json"

[cache]
# Cache strategy: TimeBased, EtagBased, Hybrid, AlwaysRefresh, NeverRefresh
strategy = "Hybrid"
# Maximum cache age in hours (default: 168 = 7 days)
max_age_hours = 168
# ETag check interval in hours (default: 24 = 1 day)
etag_check_interval_hours = 24
# Force refresh on startup
force_refresh_on_startup = false

Note: All default configuration values are defined in src/constants.rs. When you first run the application, it will create config.toml with these defaults. You can then modify config.toml to customize the behavior without changing the source code.

Custom Data Sources

You can use custom holiday data sources by modifying the source_url in config.toml. The CSV format should match the official format:

日付,祝日名
2023/1/1,元日
2023/1/2,休日
...

License