带有MySQL句柄的Node.js REST重新连接

Question

I'm new to Node.js I followed tutorial from the internet for REST API with Node.js and MySQL. I can't get it to work after MySQL closes the connection or timeout occurs. Can you tell me how to modify my code to get it work:

Server.js

var express = require("express");
var mysql   = require("mysql");
var bodyParser  = require("body-parser");
var rest = require("./REST.js");
var app  = express();

function REST(){
    var self = this;
    self.connectMysql();
};

REST.prototype.connectMysql = function() {
    var self = this;
    var pool      =    mysql.createPool({
        connectionLimit : 50,
        host     : 'localhost',
        user     : 'root',
        password : '',
        database : 'quiz',
        debug    :  false,
        multipleStatements: true
    });
    pool.getConnection(function(err,connection){
        if(err) {
          self.stop(err);
        } else {
          self.configureExpress(connection);
        }
    });
}

REST.prototype.configureExpress = function(connection) {
      var self = this;
      app.use(bodyParser.urlencoded({ extended: true }));
      app.use(bodyParser.json());
      var router = express.Router();
      app.use('/', router);
      var rest_router = new rest(router,connection);
      self.startServer();
}

REST.prototype.startServer = function() {
      app.listen(3000,function(){
          console.log("All right ! I am alive at Port 3000.");
      });
}

REST.prototype.stop = function(err) {
    console.log("ISSUE WITH MYSQL n" + err);
    process.exit(1);
}

new REST();

REST.js

var mysql = require("mysql");
function REST_ROUTER(router,connection) {
    var self = this;
    self.handleRoutes(router,connection);
}

REST_ROUTER.prototype.handleRoutes= function(router,connection) {
    router.get("/",function(req,res){
        res.json({"Message" : "Hello World !"});
    });

    router.get("/quiz/cars",function(req,res){
        var options = {sql: 'SELECT quiz.quiz_id, quiz_image, quiz_type, choice_id, choice, is_right_choice FROM quiz  JOIN quiz_choices ON quiz.quiz_id = quiz_choices.quiz_id WHERE quiz_type="cars";', nestTables: false};
        connection.query(options,function(err,rows){
            if(err) {
                res.json({"Error" : true, "Message" : "Error executing MySQL query"});
            } else {
                res.json(rows);
            }
        });
    });
}

module.exports = REST_ROUTER;

Answer 1

I have the same issue a and think this may be the solution. I made the following changes to my code:

Pass the connection pool rather than the connection to self.configureExpress() like so...

REST.prototype.connectMysql = function() {
    var self = this;
    var pool = mysql.createPool(db_config);
    self.configureExpress(pool);
};

and

REST.prototype.configureExpress = function(pool) {
....
    var rest_router = new rest(router,pool,md5);
....
}

REST.js

var mysql = require("mysql");
function REST_ROUTER(router,pool) {
    var self = this;
    self.handleRoutes(router,pool);
}

REST_ROUTER.prototype.handleRoutes= function(router,pool) {
    router.get("/",function(req,res){
        res.json({"Message" : "Hello World !"});
    });

    router.get("/quiz/cars",function(req,res){
        var options = {sql: 'SELECT quiz.quiz_id, quiz_image, quiz_type, choice_id, choice, is_right_choice FROM quiz  JOIN quiz_choices ON quiz.quiz_id = quiz_choices.quiz_id WHERE quiz_type="cars";', nestTables: false};
        pool.getConnection(function(err, connection) {
            connection.query(options,function(err,rows){
                connection.release();
                if(err) {
                    res.json({"Error" : true, "Message" : "Error executing MySQL query"});
                } else {
                    res.json(rows);
                }
            });
        });
    });
}

module.exports = REST_ROUTER;

Don't forget to call connection.release(); after you've finished using the connection so that it can be added back to the connection pool.