node.jsで同期処理を何度も忘れて、何度も調べなおしてしまうので、コードを貼り付け。
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// npm install mongodb // npm install sqlite3 run(); async function run() { console.log('run 100'); var str = await sleep(1000, 'with await'); console.log(str); // await をつけると同期 console.log('run 200'); var str = sleep(1000, 'without await'); console.log(str); // await をつけないと非同期 console.log('run 300'); requireJSON(); // require はそもそも同期 console.log('run 400'); await readFileJSON(); // fs.readFile では同期指定が必要 console.log('run 500'); readFileSyncJSON(); // fs.readFileSync はそもそも同期 console.log('run 600'); await child_process_whoami(); // 子プロセス console.log('run 700'); await child_process_sakasa_exe(); // 返り値を受け取る console.log('run 800'); await child_process_ffmpeg_exe(); // 画像生成 console.log('run 900'); await mongodb(); // mongodb への接続 console.log('run 1000'); var list = await sqlite3(); // sqlite3 への接続 console.dir(list); console.log('run 1100'); } function sleep(ms, msg) { return new Promise(resolve => { setTimeout(() => { console.log('sleep', ms, msg); resolve('comp setTimeout'); }, ms); }) } function requireJSON() { var json = require('./data.json'); console.log(json); } function readFileJSON() { return new Promise((resolve, reject) => { var fs = require('fs'); var path = "data.json"; fs.readFile(path, 'utf8', (err, data) => { console.log(data); resolve(); }); }); } function readFileSyncJSON() { var fs = require('fs'); var path = "data.json"; var str = fs.readFileSync(path, 'utf8'); console.log(str); } function child_process_whoami() { return new Promise((resolve) => { require('child_process').exec('whoami', (err, stdout, stderr) => { console.log('stdout:', stdout); resolve(stdout); }); }); } function child_process_sakasa_exe() { return new Promise((resolve) => { require('child_process').exec('sakasa.exe "Mizutama Inc."', (err, stdout, stderr) => { console.log('stdout:', stdout); resolve(stdout); }); }); } function child_process_ffmpeg_exe() { var source = 'pcloud640480.exe'; var AppPath = 'C:\\inetpub\\ffmpeg-20180820-78d4b6b-win64-static\\bin\\ffmpeg.exe'; var source = 'pcloud640480.mp4'; var out = source + '_ex_ffmpeg.exe.jpg'; var argument = ' -y -i "' + source + '" -f image2 -vframes 1 -ss 3 -an -deinterlace "' + out + '"'; var cmd = AppPath + ' ' + argument; return new Promise((resolve, reject) => { require('child_process').exec(cmd, (err, stdout, stderr) => { console.log('err:', err); console.log('stdout:', stdout); console.log('stderr:', stderr); //console.log(out); resolve(); }); }); } function mongodb() { var url = 'mongodb://127.0.0.1:27017/'; var collectionName = 'startup_log'; var mongodb = require('mongodb'); const MongoClient = mongodb.MongoClient; return new Promise((resolve) => { MongoClient.connect(url, { useNewUrlParser: true }, (err, client) => { const db = client.db('local'); var collection = db.collection(collectionName); collection.find().toArray((error, documents) => { console.log(documents); resolve(documents); }); }); }); } function sqlite3() { return new Promise((resolve, reject) => { var sqlite = require('sqlite3').verbose(); var db = new sqlite.Database('test.sqlite'); console.log('sqlite3 100'); db.serialize(() => { db.run('CREATE TABLE IF NOT EXISTS pigs(name TEXT, age INT)'); var stmt = db.prepare('INSERT INTO pigs VALUES(?,?)'); stmt.run(["boo", 5]); stmt.run(["foo", 4]); stmt.run(["woo", 3]); stmt.finalize(); console.log('sqlite3 200'); }); console.log('sqlite3 300'); db.serialize(() => { var list = []; db.each("SELECT * FROM pigs", (err, row) => { list.push(row.name + ":" + row.age); console.log(row.name + ":" + row.age); console.log('sqlite3 400'); }, (err, count) => { console.log('sqlite3 comp' + count); resolve(list); }); console.log('sqlite3 500'); }); console.log('sqlite3 600'); db.close(); console.log('sqlite3 700'); }); } |
以下、Windows PowerShellでのコマンド結果
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> node test.js run 100 sleep 1000 with await comp setTimeout run 200 Promise { <pending> } run 300 [ { group: 'pigs', name: [ 'boo', 'foo', 'woo' ] } ] run 400 [ { "group" : "pigs", "name" : ["boo","foo","woo"]} ] run 500 [ { "group" : "pigs", "name" : ["boo","foo","woo"]} ] run 600 stdout: umeha\umeha run 700 stdout: <!DOCTYPE html><html lang='en'><head><meta charset='utf-8'><title>CGI page</title></head><body>.cnI amatuziM</body></html> run 800 err: null stdout: stderr: ffmpeg version N-91646-g78d4b6bd43 Copyright (c) 2000-2018 the FFmpeg developers ～省略（ffmpegの返り値）～ erhead: unknown run 900 [ { ～省略（mongodbで取得したデータ）～ } ] run 1000 sqlite3 100 sqlite3 200 sqlite3 300 sqlite3 500 sqlite3 600 sqlite3 700 boo:5 sqlite3 400 foo:4 sqlite3 400 woo:3 sqlite3 400 sqlite3 comp3 [ 'boo:5', 'foo:4', 'woo:3' ] run 1100 sleep 1000 without await |
参考
Node.jsのMongoClientの仕様が変わってた
MongoClient.connect()時にuseNewUrlParserオプションを与える
node.jsでファイルの読み込み、新規作成、上書き、追記、削除
Node.jsでasyncモジュールを使って同期処理を行う
Node.js + MongoDBを導入する
node.jsでjsonファイルの読み込み
Node.js+express+MongoDB+Mongooseで簡単なjsonサーバを構築するメモ
Node.jsでSQLite3を使ってみる
Node.jsを使った簡単なファイル操作
今更だけどPromise入門
