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Calendar database for resource bookings using leveldb

installation

$ npm install len

usage

You create a len database by passing in an existing leveldb - this can also be a sub-level

var len = require('len');
var level = require('level');

// create a new leveldb - this can also be a sub-level
var leveldb = level('/tmp/lentest');

// create a new lem store using the leveldb
var lendb = len(db);

A booking represents a resource being used for a period of time.

Here we create a booking for bob the mechanic:


// start at 9.30
var start = new Date('04/03/14 09:30:00');
// end at 13.30
var end = new Date('04/03/14 13:30:00');

lendb.saveBooking('mechanics.bob', {
	id:14, 
	start:start,
	end:end,
	meta:{
		name:'Fix Car',
		customer:34
	}
}, function(error, booking){

	// bob is all booked in

})

We can ask len about bookings for all mechanics in a particular month:

var through = require('through');
var start = new Date('03/01/2014');
var end = new Date('04/01/2014').getTime();

var bookings_in_month = 0;

lendb.createBookingStream('mechanics', {
	start:start,
	end:end,
	// this means booking must start and end inside the window
	inclusive:true
}).pipe(through(function(booking){

	// booking is an object with 'id', 'start', 'end' and 'meta' keys
	bookings_in_month++;
	
}, function(){
	console.log('there are: ' + bookings_in_month.length + ' mechanic bookings in March');

}))

resource tree

Resources are created using paths and this can be a useful way to get booking reports at various layers.

For example - imagine we have a team that does some projects - we want to be able to ask the following questions:

the start and end point of one project
an array of bookings for one project
an array of bookings for all projects
an array of bookings between certain points for all projects

This can be done using the paths you give to resources - if we create resources with the following paths:

team.alpha.project.1
team.alpha.project.2

queries

Then we can ask for the start and end for one project:

lendb.getRange('team.alpha.project.1', function(err, bounds){
	// bounds.start = timestamp of the earliest start of booking for the project
	// bounds.end = timestamp of the latest end of booking for the project
})

get a readstream of bookings:

// bookings for one project
lendb.createBookingStream('team.alpha.project.1').pipe(through(function(booking){
	// booking is an object
}))

// bookings for one team's projects
lendb.createBookingStream('team.alpha.project')

get a readstream of bookings withing a time period

var start = new Date('03/04/14 09:30:00');
var end = new Date('03/04/14 13:30:00');

lendb.createBookingStream('team.alpha.project', {
	start:start,
	end:end
})

api

`len(leveldb);`

Create a new len database from the provided leveldb. This can be a level-sublevel so you can partition len into an existing database.

var len = require('len');
var level = require('level');

var leveldb = level('/tmp/mylem');
var lendb = len(leveldb);

`lendb.loadBooking(resourcepath, bookingid, callback)`

Fetch a booking record using the resourcepath and booking id:

lendb.loadBooking('project.1', 14, function(err, booking){

	// booking is an object with 'id', 'start', 'end' and 'meta' keys

})

`lendb.saveBooking(resourcepath, booking, callback)`

Insert/update a booking into the schedule for a resource.

booking is an object:

{
	id: 0,                   // the id of the booking you are saving - this is auto-created is left blank
	start: Date(),           // the start timestamp of the booking
	end: Date(),             // the end timestamp of the booking
	meta: {                  // an object with anything you like for the booking meta-data
		customer:12,
		comments:'apples'
	}
}

The start and end timestamps are required - the meta object is converted to a JSON string and is returned in the 'meta' property of bookings.

var start = new Date('03/04/14 09:30:00');
var end = new Date('03/04/14 13:30:00');

lendb.createBooking('project.1', {
	id:14,
	start:start,
	end:end,
	meta:{
		name:'meta data here'
	}
}, function(err){

	// the booking is created for the resource

})

`lendb.removeBooking(resourcepath, bookingid, callback)`

Remove a booking from the schedule

resource.removeBooking('project.1', 14, function(err){

	// the booking is removed

})

`lendb.getRange(resourcepath, [window], callback)`

Use this to get the start and end date for bookings in a resource

lendb.getRange('projects.1', function(err, range){
	// range.start and range.end are timestamps
})

You can also pass a window to constrain the results:

lendb.getRange('projects.1', {
	start:start,
	end:end
}, function(err, range){

	// range.start and range.end are timestamps

})

`lendb.createBookingStream(resourcepath, [window], callback)`

Use this to get an object stream of bookings for a given resource.

var through = require('through');

lendb.createBookingStream('mechanics.bob', {
	start:start,
	end:end
}).pipe(through(function(booking){

	console.log('booking found');
	console.log(booking.id);
	
}))

You can also query the booking stream using a time-window:

var through = require('through');
var start = new Date('03/01/2014');
var end = new Date('04/01/2014').getTime();

var bookings_in_month = 0;

lendb.createBookingStream('mechanics.bob', {
	start:start,
	end:end,
	inclusive:true
}).pipe(through(function(booking){

	// booking is an object with 'id', 'start', 'end' and 'meta' keys
	bookings_in_month++;
	
}, function(){
	console.log('there are: ' + bookings_in_month.length + ' bookings for bob in March');

}))

the inclusive option controls whether bookings have to start and end inside the time window (true) or if any part of it is in the time window (false)

license

MIT