sails-postgresql-live-select

A Sails connection adapter to use the pg-live-select NPM Package in order to provide live (real time) result sets for models.

Example

See the chat room example application for a full working demonstration of this package.

Installation

To be used alongside the sails-postgresql connection adapter.

1. Install the package:

   npm install --save sails-postgresql-live-select

2. Add the connection settings to your config/connections.js:

   livePg: {
     adapter: 'sails-postgresql-live-select',
     // Connection details must be passed as url, not individually
     url: 'postgres://sails:sails@localhost:5432/sails_test',
     // Unique channel required for asynchronous notifications
     channel: 'sails_test'
   }

3. Add the adapter to be used on your models, for example in config/models.js:

     connection: [ 'postgresql', 'livePg' ],

Usage

YourModel.liveFind(options, [condition])

This adapter adds a liveFind method to your models.

Argument | Type | Description ----------|------|----------- options | Object | Find options as defined by Waterline Query Language condition | Function | Optional function for validating if result set should be refreshed on row change. See condition function documentation for pg-live-select

The liveFind method returns a SelectHandle object as defined by pg-live-select.

For example, listen for the update event in your controller actions to send changes to the client:

var myLiveSelect = MyModel.liveFind({},
  function(row) {
    // Optional data invalidation callback
    // Check if data is invalidated by this row change
    console.log('Row data', row);
    return true;
  }
).on('update',
  function(diff, data) {
    // Results have changed, send to client
    sails.sockets.emit(req.socket.id, 'chatDiff', diff);
  }
);

When done listening for updates to a query, be sure to call the stop() method on the returned SelectHandle object to prevent memory leaks.

Running Tests

# Configure PostgreSQL server settings
vim test/config/connections.js
# Run suite
npm test

Test execution code is in test/config/bootstrap.js.

License

MIT