使用 node.js 產生 cli 程式

node.js cli （書摘: https://medium.freecodecamp.org/how-to-create-a-real-world-node-cli-app-with-node-391b727bbed3）

• 產生簡單 node.js binary
  • 產生 node.js 專案

    $npm init -y
    

  • 簡單的 index.js

    module.exports = () => {
    	console.log("Hello World!");
    }
    

  • 簡單的 bin 程式 /bin/outside

    #!/usr/bin/env node
    require('../')()
    

  • 將程式加入可執行

    $chmod +x ./bin/outside
    

  • 修改 package.json

    {
    //...
    "bin": {
    	"outside": "bin/outside"
    },
    //...
    }
    

  • 產生可執行程式

    $npm link
    

  • 執行

    $ outside
    Hello World
    

• 加入 command line 參數支援
  • 加入 minimist 套件

    $npm install --save minimist
    

  • 修改 index.js

    const minimist = require('minimist');
    
    module.exports = () => {
    	const args = minimist(process.argv.slice(2));
    	const cmd = args._[0] || 'help';
    
    	switch (cmd) {
    		case "today":
    			require('./cmd/today')(args);
    			break;
    		default:
    			console.log(`${cmd} is not a valid command!`);
    			break;
    	}
    }
    

  • 加入 cmd/today.js

    module.exports = (args) => {
    	console.log("Today is sunny");
    }
    

  • 執行

    $outside today
    Today is sunny
    $outside help
    help is not a valid command!
    

• 加入 version 跟 help
  • 修改 index.js

    const minimist = require('minimist');
    
    module.exports = () => {
    	const args = minimist(process.argv.slice(2));
    	const cmd = args._[0] || 'help';
    
    	switch (cmd) {
    		case "today":
    			require('./cmd/today')(args);
    			break;
    		case "help":
    			require('./cmd/help')(args);
    			break;
    		case "version":
    			require('./cmd/version')(args);
    			break;
    		default:
    			console.log(`${cmd} is not a valid command!`);
    			break;
    	}
    }
    
    

  • 加入 cmd/help

    const menus = {
    	main: `
    		outside [command] <options>
    
    		today .............. show weather for today
    		version ............ show package version
    		help ............... show help menu for a command`,
    
    	today: `
    		outside today <options>
    
    		--location, -l ..... the location to use`
    }
    
    module.exports = (args) => {
    	const subCmd = args._[0] === 'help'
    		? args._[1]
    		: args._[0]
    
    	console.log(menus[subCmd] || menus.main)
    }
    
    

  • 加入 cmd/version

    const { version } = require('../package.json');
    
    module.exports = (args) => {
    	console.log(`v${version}`);
    }
    

  • 執行

    $ outside 
    
    		outside [command] <options>
    
    		today .............. show weather for today
    		version ............ show package version
    		help ............... show help menu for a command
    $ outside help today
    
    		outside today <options>
    
    		--location, -l ..... the location to use
    $ outside version
    v1.1.0
    
    

• 這樣架構可以彈性增加功能，例如加入 10-days forecast
  • 修改 index.js

    const minimist = require('minimist');
    
    module.exports = () => {
    	const args = minimist(process.argv.slice(2));
    	const cmd = args._[0] || 'help';
    
    	switch (cmd) {
    		case "today":
    			require('./cmd/today')(args);
    			break;
    		case "help":
    			require('./cmd/help')(args);
    			break;
    		case "version":
    			require('./cmd/version')(args);
    			break;
    		case "forecast":
    			require('./cmd/forecast')(args);
    			break;
    		default:
    			console.log(`${cmd} is not a valid command!`);
    			break;
    	}
    }
    
    

  • 加入 cmd/forecast

    module.exports = (args) => {
    	console.log("This is forecast");
    }
    
    

  • 修改 cmd/help

    const menus = {
    	main: `
    		outside [command] <options>
    
    		today .............. show weather for today
    		forecast ........... show 10-day weather forecast
    		version ............ show package version
    		help ............... show help menu for a command`,
    
    	today: `
    		outside today <options>
    
    		--location, -l ..... the location to use`,
    	forecast: `
    		outside forecast <options>
    		--location, -l ... the location to use
    	`,
    }
    
    module.exports = (args) => {
    	const subCmd = args._[0] === 'help'
    		? args._[1]
    		: args._[0]
    
    	console.log(menus[subCmd] || menus.main)
    }
    

  • 執行

    $ outside help forecast
    		outside forecast <options>
    		--location, -l ... the location to use
    
    

• 實際加入氣象預測，使用 yahoo api
  • 加入 axios 跟 ora 套件

    $npm install --save axios ora
    

  • 加入 utils/weather.js

    const axios = require('axios');
    
    module.exports = async (location) => {
    	const results = await axios({
    		method: 'get',
    		url: 'https://query.yahooapis.com/v1/public/yql',
    		params: {
    			format: 'json',
    			q: `select item from weather.forecast where woeid in
    				(select woeid from geo.places(1) where text="${location}")`,
    		},
    	});
    
    	return results.data.query.results.channel.item;
    }
    
    

  • 修改 cmd/today.js

    const ora = require('ora');
    const getWeather = require('../utils/weather');
    
    module.exports = async (args) => {
    	const spinner = ora().start();
    
    	try {
    		const location = args.location || args.l ;
    		const weather = await getWeather(location);
    
    		spinner.stop();
    		console.log(`current location is ${location}`);
    		console.log(`\t ${weather.condition.temp} ${weather.condition.text}`);
    	} catch (err) {
    		spinner.stop();
    		console.log(err);
    	}
    }
    
    

  • 執行

    $outside today --location "Taipei"
    current location is Taipei
    	 91 Cloudy
    
    

  • 照樣修改 cmd/forecast.js

    const ora = require('ora');
    const getWeather = require('../utils/weather');
    
    module.exports = async (args) => {
    	const spinner = ora().start();
    
    	try {
    		const location = args.location || args.l;
    		const weather = await getWeather(location);
    
    		spinner.stop();
    		console.log(`Forecast for ${location}`);
    		weather.forecast.forEach(item => console.log(`\t ${item.date} - Low ${item.low} |High ${item.high} | ${item.text}`));
    	} catch (err) {
    		spinner.stop();
    		console.log(err);
    	}
    }
    

  • 執行

    $outside forecast --location "Taipei"
    Forecast for Taipei
    	 03 Jul 2018 - Low 83 |High 95 | Cloudy
    	 04 Jul 2018 - Low 83 |High 96 | Scattered Thunderstorms
    	 05 Jul 2018 - Low 81 |High 97 | Thunderstorms
    	 06 Jul 2018 - Low 82 |High 96 | Thunderstorms
    	 07 Jul 2018 - Low 82 |High 95 | Thunderstorms
    	 08 Jul 2018 - Low 82 |High 94 | Thunderstorms
    	 09 Jul 2018 - Low 81 |High 94 | Thunderstorms
    	 10 Jul 2018 - Low 81 |High 93 | Thunderstorms
    	 11 Jul 2018 - Low 81 |High 93 | Thunderstorms
    	 12 Jul 2018 - Low 82 |High 94 | Thunderstorms
    
    

• 加入預設區域
  • 使用 ~ipdata.io~，但須申請 API key
  • 加入 utils/location

    const axios = require('axios');
    
    module.exports = async () => {
    	const results = await axios({
    		method: 'get',
    		url: 'https://api.ipdata.co?api-key=API_KEY'
    	});
    
    	const { city, region } = results.data;
    	return `${city}, ${region}`;
    }
    
    

  • 修改 cmd/today.js

    const ora = require('ora');
    const getWeather = require('../utils/weather');
    const getLocation = require('../utils/location');
    
    module.exports = async (args) => {
    	const spinner = ora().start();
    
    	try {
    		const location = args.location || args.l || await getLocation();
    		const weather = await getWeather(location);
    
    		spinner.stop();
    		console.log(`current location is ${location}`);
    		console.log(`\t ${weather.condition.temp} ${weather.condition.text}`);
    	} catch (err) {
    		spinner.stop();
    		console.log(err);
    	}
    }
    

  • 修改 cmd/forecast.js

    const ora = require('ora');
    const getWeather = require('../utils/weather');
    const getLocation = require('../utils/location');
    
    module.exports = async (args) => {
    	const spinner = ora().start();
    
    	try {
    		const location = args.location || args.l || await getLocation();
    		const weather = await getWeather(location);
    
    		spinner.stop();
    		console.log(`Forecast for ${location}`);
    		weather.forecast.forEach(item => console.log(`\t ${item.date} - Low ${item.low} |High ${item.high} | ${item.text}`));
    	} catch (err) {
    		spinner.stop();
    		console.log(err);
    	}
    }
    

  • 執行

    $ outside
    
    		outside [command] <options>
    
    		today .............. show weather for today
    		forecast ........... show 10-day weather forecast
    		version ............ show package version
    		help ............... show help menu for a command
    $ outside today
    current location is Hsinchu, Hsinchu
    	 89 Breezy
    $ outside forecast
    Forecast for Hsinchu, Hsinchu
    	 03 Jul 2018 - Low 84 |High 92 | Breezy
    	 04 Jul 2018 - Low 84 |High 93 | Breezy
    	 05 Jul 2018 - Low 83 |High 95 | Breezy
    	 06 Jul 2018 - Low 82 |High 94 | Breezy
    	 07 Jul 2018 - Low 81 |High 94 | Breezy
    	 08 Jul 2018 - Low 81 |High 93 | Mostly Cloudy
    	 09 Jul 2018 - Low 81 |High 93 | Thunderstorms
    	 10 Jul 2018 - Low 79 |High 92 | Thunderstorms
    	 11 Jul 2018 - Low 80 |High 91 | Thunderstorms
    	 12 Jul 2018 - Low 81 |High 92 | Thunderstorms