MeCabに外部ライブラリを使わないように (#64)

package.json

@@ -20,7 +20,7 @@
     "canvas": "2.6.1",
     "chalk": "4.1.0",
     "lokijs": "1.5.11",
-    "mecab-async": "0.1.2",
+    "memory-streams": "0.1.3",
     "misskey-reversi": "0.0.5",
     "promise-retry": "2.0.1",
     "random-seed": "0.3.0",

src/modules/keyword/index.ts

@@ -3,7 +3,7 @@ import * as loki from 'lokijs';
 import Module from '../../module';
 import config from '../../config';
 import serifs from '../../serifs';
-const MeCab = require('mecab-async');
+import { mecab } from './mecab';
 
 function kanaToHira(str: string) {
 	return str.replace(/[\u30a1-\u30f6]/g, match => {
@@ -15,7 +15,6 @@ function kanaToHira(str: string) {
 export default class extends Module {
 	public readonly name = 'keyword';
 
-	private tokenizer: any;
 	private learnedKeywords: loki.Collection<{
 		keyword: string;
 		learnedAt: number;
@@ -29,9 +28,6 @@ export default class extends Module {
 			indices: ['userId']
 		});
 
-		this.tokenizer = new MeCab();
-		this.tokenizer.command = config.mecab;
-
 		setInterval(this.learn, 1000 * 60 * 60);
 
 		return {};
@@ -50,13 +46,13 @@ export default class extends Module {
 
 		let keywords: string[][] = [];
 
-		await Promise.all(interestedNotes.map(note => new Promise((res, rej) => {
-			this.tokenizer.parse(note.text, (err, tokens) => {
-				const keywordsInThisNote = tokens.filter(token => token[2] == '固有名詞' && token[8] != null);
-				keywords = keywords.concat(keywordsInThisNote);
-				res();
-			});
-		})));
+		for (const note of interestedNotes) {
+			const tokens = await mecab(note.text, config.mecab);
+			const keywordsInThisNote = tokens.filter(token => token[2] == '固有名詞' && token[8] != null);
+			keywords = keywords.concat(keywordsInThisNote);
+		}
+
+		if (keywords.length === 0) return;
 
 		const rnd = Math.floor((1 - Math.sqrt(Math.random())) * keywords.length);
 		const keyword = keywords.sort((a, b) => a[0].length < b[0].length ? 1 : -1)[rnd];

src/modules/keyword/mecab.ts

@@ -0,0 +1,45 @@
+import { spawn } from 'child_process';
+import * as util from 'util';
+import * as stream from 'stream';
+import * as memoryStreams from 'memory-streams';
+import { EOL } from 'os';
+
+const pipeline = util.promisify(stream.pipeline);
+
+/**
+ * Run MeCab
+ * @param text Text to analyze
+ * @param mecab mecab bin
+ * @param dic mecab dictionaly path
+ */
+export async function mecab(text: string, mecab = 'mecab', dic?: string): Promise<string[][]> {
+	const args: string[] = [];
+	if (dic) args.push('-d', dic);
+
+	const lines = await cmd(mecab, args, `${text.replace(/[\n\s\t]/g, ' ')}\n`);
+
+	const results: string[][] = [];
+
+	for (const line of lines) {
+		if (line === 'EOS') break;
+		const [word, value = ''] = line.split('\t');
+		const array = value.split(',');
+		array.unshift(word);
+		results.push(array);
+	}
+
+	return results;
+}
+
+export async function cmd(command: string, args: string[], stdin: string): Promise<string[]> {
+	const mecab = spawn(command, args);
+
+	const writable = new memoryStreams.WritableStream();
+
+	mecab.stdin.write(stdin);
+	mecab.stdin.end();
+
+	await pipeline(mecab.stdout, writable);
+
+	return writable.toString().split(EOL);
+}