Enable emergency shutoff support

src/bot.js

@@ -139,6 +139,18 @@ class mwn {
 			// shutoffPage: null,
 			// shutoffRegex: /^\s*$/,
 
+			/**
+			 * Bot emergency shutoff options
+			 * @type {{condition: RegExp | Function, page: string,
+			 * intervalDuration: number, onShutoff: Function}}
+			 */
+			shutoff: {
+				intervalDuration: 10000,
+				page: null,
+				condition: /^\s*$/,
+				onShutoff: function () {}
+			},
+
 			// default parameters included in every API request
 			defaultParams: {
 				format: 'json',
@@ -198,6 +210,15 @@ class mwn {
 			responseType: 'json'
 		}, mwn.requestDefaults);
 
+		/**
+		 * Emergency shutoff config
+		 * @type {{hook: ReturnType<typeof setTimeout>, state: boolean}}
+		 */
+		this.shutoff = {
+			state: false,
+			hook: null
+		};
+
 		/**
 		 * Title class associated with the bot instance
 		 */
@@ -409,6 +430,14 @@ class mwn {
 	 * @returns {Promise<Object>}
 	 */
 	async request(params, customRequestOptions = {}) {
+
+		if (this.shutoff.state) {
+			return this.rejectWithError({
+				code: 'bot-shutoff',
+				info: `Bot was shut off (check ${this.options.shutoff.page})`
+			});
+		}
+
 		params = merge(this.options.defaultParams, params);
 
 		const getOrPost = function (data) {
@@ -865,6 +894,41 @@ class mwn {
 		});
 	}
 
+	/**
+	 * Enable bot emergency shutoff
+	 * @param {Object} [shutoffOptions]
+	 * @config {string} [page]
+	 * @config {number} [intervalDuration]
+	 * @config {RegExp | Function} [condition]
+	 * @config {Function} [onShutoff]
+	 */
+	enableEmergencyShutoff(shutoffOptions) {
+		Object.assign(this.options.shutoff, shutoffOptions);
+
+		this.shutoff.hook = setInterval(async () => {
+			let text = await new this.page(this.options.shutoff.page).text();
+			let cond = this.options.shutoff.condition;
+			if (
+				(cond instanceof RegExp && !cond.test(text)) ||
+				(cond instanceof Function && !cond(text))
+			) {
+				this.shutoff.state = true;
+				this.disableEmergencyShutoff();
+				// user callback executed last, so that an error thrown by
+				// it doesn't prevent the the above from being run
+				this.options.shutoff.onShutoff(text);
+			}
+		}, this.options.shutoff.intervalDuration);
+	}
+
+	/**
+	 * Disable emergency shutoff detection.
+	 * Use this only if it was ever enabled.
+	 */
+	disableEmergencyShutoff() {
+		clearInterval(this.shutoff.hook);
+	}
+
 	/***************** HELPER FUNCTIONS ******************/
 
 	/**

tests/shutoff.test.js

@@ -0,0 +1,62 @@
+'use strict';
+
+const { bot, expect, loginBefore, logoutAfter} = require('./test_base');
+
+
+describe('bot emergency shutoff', async function() {
+	this.timeout(10000);
+
+	before('logs in and gets token & namespaceInfo', loginBefore);
+	after('logs out', logoutAfter);
+
+	it('set shutoff=true on non-matching regex', async function () {
+		bot.enableEmergencyShutoff({
+			page: 'SD0001test',
+			intervalDuration: 1000,
+			condition: /^\s*$/
+		});
+		await bot.save('SD0001test', 'shutoff', 'Testing bot shutoff (mwn)');
+		await bot.sleep(1500); // wait till we can be sure that shutoff check is queried
+		expect(bot.shutoff.state).to.equal(true);
+		bot.disableEmergencyShutoff();
+	});
+
+	it('set shutoff=true on condition function returns falsy value', async function () {
+		bot.shutoff.state = false; // restore to default state
+
+		bot.enableEmergencyShutoff({
+			page: 'SD0001test',
+			intervalDuration: 1000,
+			condition: function () {
+				return false; // function returns false means bot would shut down
+			}
+		});
+		await bot.sleep(1500); // wait till we can be sure that shutoff check is queried
+		expect(bot.shutoff.state).to.equal(true);
+		bot.disableEmergencyShutoff();
+	});
+
+	it ('sets shutoff=true even if shutoff options are not configured in function', async function () {
+		bot.shutoff.state = false; // restore to default state
+
+		bot.options.shutoff.page = 'SD0001test';
+		bot.options.shutoff.intervalDuration = 1000;
+		bot.options.shutoff.condition = /^\s*$/;
+		bot.enableEmergencyShutoff();
+		await bot.save('SD0001test', 'shutoff', 'Testing bot shutoff (mwn)');
+		await bot.sleep(1500); // wait till we can be sure that shutoff check is queried
+		expect(bot.shutoff.state).to.equal(true);
+		bot.disableEmergencyShutoff();
+	});
+
+	it('refuses to do API requests when shut off', function () {
+		bot.shutoff.state = true;
+		return bot.request({action: 'query', titles: 'testtitle'})
+			.then(() => {
+				expect(true).to.equal(false); // should never execute
+			}, (err) => {
+				expect(err.code).to.equal('bot-shutoff');
+			});
+	});
+
+});