Connect/Express middleware provides a consistent API for MySQL connections during request/response life cycle. It supports three different strategies of managing db connections: single for a singleton connection on an app instance level, pool based connections, and a new connection per each request. It’s also capable of auto closing/releasing connections if configured either with pool or request. It uses node-mysql as a MySQL driver.

• single - creates single database connection for an application instance. Connection is never closed. In case of disconnection it will try to reconnect again as described in node-mysql docs.
• pool - creates pool of connections on an app instance level, and serves a single connection from pool per request. The connections is auto released to the pool at the response end.
• request - creates new connection per each request, and automatically closes it at the response end.

Configuration is straightforward and you use it as any other middleware. First param it accepts is a node-mysql module, second is a db options hash passed to node-mysql module when connection or pool are created. The third is string defining strategy type.

// app.js
...
var mysql = require('mysql'), // node-mysql module
    myConnection = require('express-myconnection'), // express-myconnection module
    dbOptions = {
      host: 'localhost',
      user: 'dbuser',
      password: 'password',
      port: 3306,
      database: 'mydb'
    };
  
app.use(myConnection(mysql, dbOptions, 'single');
...

express-myconnection extends request object with getConection(callback) function, this way connection instance can be accessed anywhere in routers during request/response life cycle:

// myroute.js
...
module.exports = function(req, res, next) {
    ...
    req.getConnection(function(err, connection) {
      if (err) return next(err);
      
      connection.query('SELECT 1 AS RESULT', [], function(err, results) {
        if (err) return next(err);
        
        results[0].RESULT;
        // -> 1
        
        res.send(200);
      });
      
    });
    ...
}
...