misskey/packages/backend/src/core/UtilityService.ts

/*
 * SPDX-FileCopyrightText: syuilo and misskey-project
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { URL } from 'node:url';
import { toASCII } from 'punycode';
import { Inject, Injectable } from '@nestjs/common';
import RE2 from 're2';
import { DI } from '@/di-symbols.js';
import type { Config } from '@/config.js';
import { bindThis } from '@/decorators.js';

@Injectable()
export class UtilityService {
	constructor(
		@Inject(DI.config)
		private config: Config,
	) {
	}

	@bindThis
	public getFullApAccount(username: string, host: string | null): string {
		return host ? `${username}@${this.toPuny(host)}` : `${username}@${this.toPuny(this.config.host)}`;
	}

	@bindThis
	public isSelfHost(host: string | null): boolean {
		if (host == null) return true;
		return this.toPuny(this.config.host) === this.toPuny(host);
	}

	@bindThis
	public isBlockedHost(blockedHosts: string[], host: string | null): boolean {
		if (host == null) return false;
		return blockedHosts.some(x => `.${host.toLowerCase()}`.endsWith(`.${x}`));
	}

	@bindThis
	public isSilencedHost(silencedHosts: string[] | undefined, host: string | null): boolean {
		if (!silencedHosts || host == null) return false;
		return silencedHosts.some(x => `.${host.toLowerCase()}`.endsWith(`.${x}`));
	}

	@bindThis
	public isKeyWordIncluded(text: string, keyWords: string[]): boolean {
		if (keyWords.length === 0) return false;
		if (text === '') return false;

		const regexpregexp = /^\/(.+)\/(.*)$/;

		const matched = keyWords.some(filter => {
			// represents RegExp
			const regexp = filter.match(regexpregexp);
			// This should never happen due to input sanitisation.
			if (!regexp) {
				const words = filter.split(' ');
				return words.every(keyword => text.includes(keyword));
			}
			try {
				// TODO: RE2インスタンスをキャッシュ
				return new RE2(regexp[1], regexp[2]).test(text);
			} catch (err) {
				// This should never happen due to input sanitisation.
				return false;
			}
		});

		return matched;
	}

	@bindThis
	public extractDbHost(uri: string): string {
		const url = new URL(uri);
		return this.toPuny(url.hostname);
	}

	@bindThis
	public toPuny(host: string): string {
		return toASCII(host.toLowerCase());
	}

	@bindThis
	public toPunyNullable(host: string | null | undefined): string | null {
		if (host == null) return null;
		return toASCII(host.toLowerCase());
	}
}