dahabit / meteor-mysql

Reactive MySQL for Meteor

numtel:mysql

Reactive MySQL for Meteor

Provides Meteor integration of the mysql-live-select NPM module, bringing reactive SELECT statement result sets from MySQL >= 5.1.15.

• How to publish joined queries that update efficiently
• Leaderboard example modified to use MySQL
• Talk at Meteor Devshop SF, December 2014

This documentation covers numtel:mysql >= 0.1.0. For older versions that included the trigger poll table that worked with MySQL < 5.1.15, see the old branch.

Server Implements

This package provides the LiveMysql class as defined in the mysql-live-select NPM package. Be sure to follow the installation instructions for configuring your MySQL server to output the binary log.

LiveMysql.prototype.select()

In this Meteor package, the LiveMysqlSelect object returned by the select() method is modified to act as a cursor that can be published.

var liveDb = new LiveMysql(Meteor.settings.mysql);

Meteor.publish('allPlayers', function(){
  return liveDb.select(
    `SELECT * FROM players ORDER BY score DESC`,
    [ { table: 'players' } ]
  );
});

Client/Server Implements

MysqlSubscription([connection,] name, [args...])

Constructor for subscribing to a published select statement. No extra call to Meteor.subscribe() is required. Specify the name of the subscription along with any arguments.

The first argument, connection, is optional. If connecting to a different Meteor server, pass the DDP connection object in this first argument. If not specified, the first argument becomes the name of the subscription (string) and the default Meteor server connection will be used.

The prototype inherits from Array and is extended with the following methods:

Name	Description
addEventListener(eventName, listener)	Bind a listener function to this subscription
removeEventListener(eventName)	Remove listener functions from an event queue
dispatchEvent(eventName, [args...])	Call the listeners for a given event, returns boolean
depend()	Call from inside of a Template helper function to ensure reactive updates
reactive()	Same as depend() except returns self
changed()	Signal new data in the subscription
ready()	Return boolean value corresponding to subscription fully loaded
stop()	Stop updates for this subscription

Notes:

• changed() is automatically called when the query updates and is most likely to only be called manually from a method stub on the client.
• Event listener methods are similar to native methods. For example, if an event listener returns false exactly, it will halt listeners of the same event that have been added previously. A few differences do exist though to make usage easier in this context:
  • The event name may also contain an identifier suffix using dot namespacing (e.g. update.myEvent) to allow removing/dispatching only a subset of listeners.
  • removeEventListener() and dispatchEvent() both refer to listeners by name only. Regular expessions allowed.
  • useCapture argument is not available.

Event Types

Name	Listener Arguments	Description
update	index, msg	Any difference, before update
added	index, newRow	Row inserted, after update
changed	index, oldRow, newRow	Row updated, after update
removed	index, oldRow	Row removed, after update
reset	msg	Subscription reset (most likely due to code-push), before update

Closing connections between hot code-pushes

With Meteor's hot code-push feature, a new connection the database server is requested with each restart. In order to close old connections, a handler to your application process's SIGTERM signal event must be added that calls the end() method on each LiveMysql instance in your application. Also, a handler for SIGINT can be used to close connections on exit.

On the server-side of your application, add event handlers like this:

var liveDb = new LiveMysql(Meteor.settings.mysql);

var closeAndExit = function() {
  liveDb.end();
  process.exit();
};

// Close connections on hot code push
process.on('SIGTERM', closeAndExit);
// Close connections on exit (ctrl + c)
process.on('SIGINT', closeAndExit);

Tests / Benchmarks

A MySQL server configured to output the binary log in row mode is required to run the test suite.

The MySQL connection settings must be configured in test/settings/local.json.

The database specified should be an empty database with no tables because the tests will create and delete tables as needed.

If you set the recreateDb value to true, the test suite will automatically create the database, allowing you to specify a database name that does not yet exist.

# Install Meteor
$ curl -L https://install.meteor.com/ | /bin/sh

# Clone Repository
$ git clone https://github.com/numtel/meteor-mysql.git
$ cd meteor-mysql

# Configure database settings in your favorite editor
# (an empty database is suggested)
$ ed test/settings/local.json

# Run test/benchmark server
$ meteor test-packages --settings test/settings/local.json ./

License

MIT