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node-task/node_modules/express-myconnection/README.md

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2014-09-23 14:54:05 -04:00
express-myconnection
============
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`. Its also capable of auto closing/releasing connections if configured either with `pool` or `request`. It uses [node-mysql](https://github.com/felixge/node-mysql) as a MySQL driver.
### Strategies
* `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](https://github.com/felixge/node-mysql).
* `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.
### Usage
Configuration is straightforward and you use it as any other middleware. First param it accepts is a [node-mysql](https://github.com/felixge/node-mysql) module, second is a db options hash passed to [node-mysql](https://github.com/felixge/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);
});
});
...
}
...