Introduction

Node-queue is a node.js module for multiple databases. It can be very useful if you work with (d)ddd, cqrs, eventsourcing, commands and events, etc.

Installation

$ npm install node-queue

Usage

Connecting to an in-memory queue

var queue = require('node-queue');

queue.createQueue(function(err, myQueue) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    // you can now use myQueue variable to go on...
});

Connecting to any queue (mongodb in the example)

Make shure you have installed the required driver, in this example run: 'npm install mongodb'.

var queue = require('node-queue');

queue.createQueue(
    {
        type: 'mongoDb',
        host: 'localhost',      // optional
        port: 27017,            // optional
        dbName: 'queuedb',      // optional
        collectionName: 'queue' // optional
        timeout: 10000          // optional
    },
    function(err, myQueue) {
        if(err) {
            console.log('ohhh :-(');
            return;
        }

        // you can now use myQueue variable to go on...
    }
);

Pushing...

myQueue.push('myId', { some: 'data' }, function(err) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }
});

Removing...

myQueue.remove('myId',  function(err) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }
});

Check if is already queued

myQueue.isQueued('myId',  function(err, isQueued) {
    if(isQueued) {
        console.log('Already queued!');
    } else {
        console.log('Not queued!');
    }
});

Getting all...

myQueue.getAll(function(err, items) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    // items is an array of all what is in the queue
    var firstItem = items[0];
    console.log('the id: ' + firstItem.id);
    console.log('the pushed data: ' + firstItem.data);
});

Obtain a new id

myQueue.getNewId(function(err, newId) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    console.log('the new id is: ' + newId);
});

Catch connect ad disconnect events

var q = queue.createQueue({ type: 'mongodb' }, function(err, q) {
    console.log('hello from callback');
    // use queue here...
});
q.on('connect', function() {
    console.log('hello from event');
    // or here
});
q.on('disconnect', function() {
    console.log('bye');
});

Decrement (can be very useful if you want to create a eventQueue for eventdenormalizers, cqrs, eventsourcing)

// if you push yout items with a workers property...
myQueue.push('myId', { some: 'data', workers: 2 }, function(err) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

});

...

// then you can decrement the workers property
myQueue.decrement('myId', function(err, hasBeenRemoved) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    // Now the workers value is decremented,
    // but if the workers value after the decrement is 0,
    // the record will be automatically removed.
    // You can check this with the flag hasBeenRemoved!

    if(hasBeenRemoved) {
        console.log('All workers finished!');
    }

});

#Release notes

Database Support

Currently these databases are supported:

1. inmemory
2. mongodb ([node-mongodb-native] (https://github.com/mongodb/node-mongodb-native))
3. couchdb ([cradle] (https://github.com/cloudhead/cradle))
4. tingodb ([tingodb] (https://github.com/sergeyksv/tingodb))
5. redis ([redis] (https://github.com/mranney/node_redis))

own db implementation

You can use your own db implementation by extending this... (pass the Queue as type in the options)

var Queue = require('node-queue').Queue,
util = require('util'),
    _ = require('lodash');

function MyDB(options) {
  Queue.call(this, options);
}

util.inherits(MyDB, Queue);

_.extend(MyDB.prototype, {

  ...

});

module.exports = MyDB;

License

Copyright (c) 2015 Adriano Raiano

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.