回答編集履歴
1
createConnectionの使い方の変化に追従出来るよう修正
answer
CHANGED
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@@ -81,7 +81,8 @@
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81
81
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// mysql2にはPromise動作モードというのがある
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82
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const mysql = require("mysql2/promise");
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83
83
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84
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-
// ここは
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84
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+
// ここはこのままで構わない
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85
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// ただし返り値がPromiseのインスタンスになっており、一度thenを叩いて本物のコネクションを取り出す必要がある
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85
86
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const connection = mysql.createConnection({
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86
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host: 'localhost',
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87
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user: 'root',
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@@ -92,17 +93,18 @@
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92
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app.post('/select', (req, res) => {
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93
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const variables = {};
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94
95
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96
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// connection.thenを基点に展開する
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95
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-
connection.query(
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97
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connection.then(c => c.query(
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96
98
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'SELECT date, temperature, humidity FROM data WHERE device = ? ORDER BY date ASC;',
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97
99
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[req.body.device]
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98
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-
).then(results => {
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100
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+
)).then(results => {
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99
101
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console.log(results);
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100
102
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variables.items = results;
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101
103
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102
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-
return connection.query(
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104
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+
return connection.then(c => c.query(
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103
105
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'SELECT * FROM data where date=(select max(date) from data where device = ?);',
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104
106
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[req.body.device]
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105
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-
);
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107
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+
));
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106
108
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}).then(results => {
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107
109
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console.log(results);
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108
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variables.news = results;
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@@ -135,11 +137,12 @@
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135
137
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// 普通のアロー関数の前にasyncというワードを付与するだけ
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136
138
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app.post('/select', async (req, res) => {
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137
139
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// awaitを使うとPromise.then(val => {})を実行してvalを取り出すコードに変換される
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140
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const c = await connection;
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138
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-
const items = await
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141
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const items = await c.query(
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139
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'SELECT date, temperature, humidity FROM data WHERE device = ? ORDER BY date ASC;',
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140
143
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[req.body.device]
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141
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);
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142
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-
const news = await
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145
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+
const news = await c.query(
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143
146
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'SELECT * FROM data where date=(select max(date) from data where device = ?);',
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144
147
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[req.body.device]
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145
148
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);
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@@ -162,6 +165,7 @@
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162
165
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app.post('/select', async (req, res) => {
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163
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const val = {};
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164
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try {
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168
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+
const c = await connection;
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165
169
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const items = await connection.query(
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166
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'SELECT date, temperature, humidity FROM data WHERE device = ? ORDER BY date ASC;',
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167
171
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[req.body.device]
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