避免 Node.js 应用程序因 node-mysql 错误而崩溃

Question

在我创建的场景中，我关闭了数据库并尝试执行如下查询：

router.get('/manga/updatescores', function(req, res) {

    pool.getConnection(function(err, connection) {

        connection.query('select * from foobar', function(err, rows) {
        // ...
        }
    });

    // ...
}

并得到如下日志：

C:\Users\Void\Documents\node-training\test-mysql\controller\routes.js:201
                        connection.query('select * from foobar', function(err, rows) {
                                  ^

TypeError: Cannot read property 'query' of undefined
    at C:\Users\Void\Documents\node-training\test-mysql\controller\routes.js:201:14
    at Handshake.onConnect (C:\Users\Void\Documents\node-training\test-mysql\node_modules\mysql\lib\Pool.js:54:9)
    at Handshake.Sequence.end (C:\Users\Void\Documents\node-training\test-mysql\node_modules\mysql\lib\protocol\sequences\Sequence.js:96:24)
    at Protocol.handleNetworkError (C:\Users\Void\Documents\node-training\test-mysql\node_modules\mysql\lib\protocol\Protocol.js:364:14)
    at PoolConnection.Connection._handleNetworkError (C:\Users\Void\Documents\node-training\test-mysql\node_modules\mysql\lib\Connection.js:421:18)
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at emitErrorNT (net.js:1253:8)
    at nextTickCallbackWith2Args (node.js:442:9)
    at process._tickCallback (node.js:356:17)

npm ERR! Windows_NT 6.3.9600
npm ERR! argv "C:\Program Files\nodejs\node.exe" "C:\Program Files\nodejs\node_modules\npm\bin\npm-cli.js" "start"
npm ERR! node v4.4.3
npm ERR! npm  v2.15.1
npm ERR! code ELIFECYCLE
npm ERR! test-mysql@1.0.0 start: `node server.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the test-mysql@1.0.0 start script 'node server.js'.
npm ERR! This is most likely a problem with the test-mysql package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node server.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs test-mysql
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!
npm ERR!     npm owner ls test-mysql
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     C:\Users\Void\Documents\node-training\test-mysql\npm-debug.log

出于某种原因，此错误只会停止服务器。当然，我有几种方法来处理这个错误。但我想知道的是，是否有某种用于 Express 的中间件可以避免有人没有预见到停止服务器的未捕获错误？

谢谢！

Answer 1

您可以使用 'promise-mysql' 并捕获所有异常。参考：https://github.com/lukeb-uk/node-promise-mysql

var mysql = require('promise-mysql');
var connection;
mysql.createConnection({
    host: 'localhost',
    user: 'sauron',
    password: 'theonetruering',
    database: 'mordor'
}).then(function(conn){
    connection = conn;
}).catch(function(error){
    //logs out the error
    console.log(error);
});

避免 Node.js 应用程序因 node-mysql 错误而崩溃

Avoid Node.js application from crashing with node-mysql error

node.js

express

node-mysql