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 concatNoteContentsForKeyWordCheck(content: {
		cw?: string | null;
		text?: string | null;
		pollChoices?: string[] | null;
		others?: string[] | null;
	}): string {
		/**
		 * ノートの内容を結合してキーワードチェック用の文字列を生成する
		 * cwとtextは内容が繋がっているかもしれないので間に何も入れずにチェックする
		 */
		return `${content.cw ?? ''}${content.text ?? ''}\n${(content.pollChoices ?? []).join('\n')}\n${(content.others ?? []).join('\n')}`;
	}

	@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());
	}
}