node.jsでの同期処理 – 水玉製作所

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。

// 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');
  });
}

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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

> 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

> 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:

～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

スマホのブラウザで即参加！

スマホのブラウザで即参加！

スマホのブラウザで即参加！

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